The Journal of Gemmology Volume 26 No. 2 April 1998
The Gemmological Association and Gem Testing Laboratory of Great Britain Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street, London EC1N 8SU Tel: 01714043334 Fax: 01714048843 e-mail: [email protected] Website: www.gagtl.ac.uk/gagtl President: Professor RA Howie Vice-Presidents: E.M. Bruton, AE. Faro, D.G. Kent, RK. Mitchell Honorary Fellows: RA Howie, R.T. Liddicoat Jill, K. Nassau Honorary Life Members: D.J. Callaghan, E.A Jobbins, H. Tillander Council of Management: CR Cavey, T.J. Davidson, N.W.. Deeks, RR Harding, I. Thomson, V.P. Watson Members' Council: AJ. Allnutt, P. Dwyer-Hickey, R Fuller, J. Greatwood, B. Jackson, J. Kessler, J. Monhickendam, 1. Music, J.B. Nelson, P.G. Read, R Shepherd, CH. Winter Branch Chairmen: Midlands ~ G.M. Green, North West -I. Knight, Scottish - B. Jackson Examiners: AJ. Allnutt, M.5c., Ph.D., FGA, S.M. Anderson, B.Sc. (Hons), FGA, 1. Bartlett, B.Sc., M.Pbil., FGA, DGA, E.M. Bruton, FGA, DGA, CR Cavey, .FGA, S. Coelho, B.Sc., FGA, DGA, Prof. AT. Collins, B.Sc., Ph.D, AG. Good, FGA, DGA, CJ.E. Hall, B.Sc. (Hons), FGA, G.M .. Howe, FGA, DGA, G.H. Jones, B.5c., Ph.D., FGA, M. Newton, B.Sc., D.Phil.,H.1. Plumb, B.Sc., FGA, DGA, RD. Ross, B.Sc., FGA, DCA, P.A Sadler, B.5c., FCA, DCA, E. Stern, FGA, DGA, P rof. I. Sunagawa, D.5c., M. Tilley, GG, FGA, CM. Woodward, B.Sc .., FGA, DGA The Journal of Gemmology Editor: Dr RR Harding Assistant Editors: M.J. O'Donoghue, P.G. Read Associate Editors: S.M. Anderson (London), Dr CE.s. Arps (Leiden), G. Bosshart (Zurich), Prof. AT. Collins (London), Dr J.w. Harris (Glasgow), Prof. RA Howie (Derbyshire), Dr J.M. Ogden (Cambridge), Prof. AH. Rankin (Kingston upon Thames), Dr J.E. Shigley (Carlsbad), Prof. D.C Smith (Paris), E. Stern (London), Prof. I. Sunagawa (Tokyo), Dr M. Superchi (Milan), CM. Woodward (London) Production Editor: M.A Burland
Vol 26. No.2, April 1998 ISSN: 1355-4565 Distinctive gem corundum suites from discrete basalt fields: a comparative study of Barrington, Australia, and West Pailin, Cambodia, gemfields
F.L. Sutherland1, D. Schwarz2, E.A. Jobbins3, R.R. Coenraads1 and G. Webb1 1. Geodiversity Research Group, Australian Museum, Sydney, Australia 2. Giibelin Gemmological Laboratory, Lucerne, Switzerland 3. Caterham, Surrey, U.K.
ABSTRACT: Barrington, Australia, and West Pailin, Cambodia, basalt fields yield remarkably similar 'metamorphic' corundums (including ruby) and 'basaltic' type blue corundums. These represent different underlying sources tapped by basaltic eruptions. The 'metamorphic' suites have high chromium/low gallium chemistry, with Ga203 contents <0.01 wt% and Cr203/Ga203 ratios above 3. The 'basaltic' suites show higher Ga203 (up to 0.04 wt%) and Cr203/Ga203 ratios below 1. The 65 absorption spectra of blue 'metamorphic' sapphires are dominated by Fe3+ bands in the ultraviolet (375, 387 nm) and visible region (450, 460, 469 nm). A broad Fe2+ - Ti4+ charge transfer band lies between 550-750 nm, without significant Fe2+ - Fe3+ charge transfer absorption toward the near infrared that is typical of blue 'basaltic' sapphires. Most absorption spectra of 'metamorphic' corundums represent a combination of Fe/Ti/Cr-bands, with variable relative intensities.
Keywords: corundum, sapphire, ruby, sapphirine, absorption spectra, trace elements, basalt, Barrington (Australia), Pailin (Cambodia)
Introduction widely separated basalt fields, Barrington in Fast Australia and South East Asia East Australia and West Pailin in Cambodia, exploit rich corundum deposits from and show that they contain mixed ruby and • / their basalt fields, in significant mining, sapphire suites of remarkable similarity. processing and cutting industries (Mumme, Two distinctive gem corundum suites 1988; Hughes, 1990, 1997). East Australia appear in eluvial and alluvial deposits produces sapphire and rare ruby (Coldham, from the Barrington basalt province in 1985; Olliver and Townsend, 1990; Sutherland, New South Wales, one typical of East 1991), while SE Asia produces both sapphire Australian sapphire fields and the other and ruby in abundance (Vichit, 1992). In this associated with rubies (Sutherland and paper we describe corundum suites from two Coenraads, 1996). Besides typical Australian
© Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355-4565 corrodedcorroded blue-green-yelloblue-green-yelloww zonedzoned sapphiressapphires PreliminaryPreliminary examinationexamination ooff WesWestt PailinPailin (Coenraads,(Coenraads, 1992a,1992a, b;b; Sutherland,Sutherland, 1996;1996; GuoGuo etet materiamateriall showedshowed itsits similaritysimilarity ttoo thethe al.,al, 1996),1996), ththee BarringtonBarrington provinceprovince alsoalso yieldyieldss BarringtoBarringtonn suites,suites, includingincluding sapphirinesapphirine aass anan anan abundantabundant pastel-colouredpastel-coloured sapphire-rubysapphire-ruby intergrowthintergrowth inin thethe rubyruby associationassociation (analysis(analysis suitesuite (Sutherland(Sutherland et al.,al, 1993;1993; SutherlandSutherland andand bbyy K.K. Williams).Williams). A mormoree detaileddetailed Coenraads,Coenraads, 1996).1996). RecognitionRecognition ofof thisthis lastlast suitesuite investigationinvestigation ofof samplessamples collectedcollected bbyy JobbinsJobbins promptedprompted a re-examinatiore-examinationn ofof rubyruby andand waswas carriedcarried outout byby personnepersonnell frofromm thethe sapphiresapphire collectedcollected fromfrom basaltbasalt fieldsfields aroundaround AustraliaAustraliann MuseumMuseum anandd GiibelinGiibelin PailiPailinn byby E.A.E.A. JobbinsJobbins inin 19741974 (Berrange(Berrangé andand GemmologicalGemmological Laboratory,Laboratory, Switzerland.Switzerland. ThisThis JobbinsJobbins,, 1976;1976; JobbinsJobbins andand Berrange,Berrangé, 1981).1981). worworkk includesincludes gemmologicalgemmological studiestudiess onon
Figure 1: Distribution ofof basaltic basaltic rocks rocks (stippled (stippled areas) areas) and mainand maindrainages, drainages, Barrington Barrington volcano volcano province, 250 250 km km north north of ofSydney, Sydney, New New South South Wales. Wales. Corundum/zircon Corundum/zircon suites suitesare marked are marked by inclined by inclined crosses. The The numbered numbered sites sites are are basalt basalt age-dating age-dating sites, sites,with thewith following the following ages, 1: ages, 44-54 1: m.y., 44-54 1A: m.y., 1A: 54 m.y.,m.y., 2:2: 3737 m.y.,m.y., 2A:2A: 4242 m.y., m.y., 3: 3: 52-54 52-54 m.y., m.y., 4: 4: 59 59 m.y., m.y., 5: 5: 54 54 m.y. m.y. (based (based on onSutherland Sutherland and and Fanning, 1996). 1996). The The main main intrusive intrusive centre centre of Barrington of Barrington volcano volcano is marked is markedby a triangle by a (1555triangle m above (1555 m above sea level) andand the the original original extent extent of ofthe the volcano volcano before before dissection dissection is marked is marked by a dashed by a dashedperimeter perimeter (600-800 m m a.s.l.), a.s.L), after after Pain, Pain, 1983. 1983.
66 66
J.J . Gemm., 1998, 1998,26,2, 26, 2, 65-85 65-85 3km j N
67 67
Figure 2: Distribution of basaltic rocks (denser stippled areas) and drainages, Pailin district,district, Cambodia.Cambodia . Gem-bearing drainage is shown as continuous lines, with gem-barren drainages shown as short dashed lines. Volcanic ventsvents areare indicatedindicated byby trianglestriangles andand thethe mainmain basaltbasalt centrescentres areare PhnumPhnum KoKo Ngoap, Phnum 0O Tang forfor dominant fancyfancy coloured corundums, and Phnum Yat forfor dominant 'basaltic''basaltic' blueblue corundums. The main drainages are the O0 Chra and Stoeng Pailin rivers and the road toto Pailin is marked by a double line.line. The geological boundaryboundary betweenbetween youngeryounger basementbasement rocksrocks (coarse(coarse stipple) and older crystalline basement (unmarked) isis shown by a heavy line,line, and fault zones are markedmarked by long dashes.dashes. Diagram modified fromfrom BerrangéBerrange and Jobbins, 1976, and Jobbins andand Berrange,Berrangé, 1981.1981. corunducorundumm frofromm BarringtoBarringtonn anandd WesWestt PailiPallinn (CAMEC(CAMECAA microprobmicroprobee witwithh WDWDSS spectrospectro anandd comparativcomparativee studiestudiess oonn sapphiresapphiress fromfrom metermeter;; R.RRR.. CoenraadsCoenraads,, F.LF.L.. SutherlandSutherland)) anandd EasEastt AustraliaAustralia,, frofromm centracentrall QueenslandQueensland comparisoncomparisonss ooff ththee corunducorundumm suitesuitess iinn (Anaki(Anakiee FieldsFields)) anandd NeNeww SoutSouthh WaleWaless discussiodiscussionn ooff theitheirr geologicageologicall originoriginss (Ne(Neww EnglanEnglandd FieldsFields)) anandd frofromm EasEastt PailinPallin.. (F.L(F.L.. Sutherland,Sutherland, D.D. Schwarz).Schwarz). StudieStudiess includincludee photographphotographyy anandd photophoto micrography (G. Webb, E.A. Jobbins), trace micrography (G. Webb, E.A. Jobbins), trace GeologicaGeologicall settingsettingss elemenelementt anandd coloucolourr absorptioabsorptionn spectraspectrall studiestudiess (EDXRF(EDXRF,, UV-vis-NIUV-vis-NIRR spectrometry;spectrometry; ThThee BarringtoBarringtonn corundumcorundumss comcomee frofromm ththee DD.. Schwarz)Schwarz),, chemicachemicall analyseanalysess ooff inclusioninclusionss erodeerodedd BarringtoBarringtonn shielshieldd volcanvolcanoo iinn anandd intergrowthintergrowthss iinn WesWestt PailiPallinn corundumscorundums NeNeww SoutSouthh WaleWaless withiwithinn ththee CainozoiCainozoicc
DistinctiveDistinctive gem corundumccrrundum suitessuites fromfrom discrete basaltbasalt fields Figure 3: Working eluvial/alluvialeluviallalluvial gem gravels on the banks of a small stream about 0.4 km south-west of the Phnum Ko Ngoap vent. The analysed West Pailin specimens are from this locality. Photograph by E.A. Jobbins. Figure 4: Washing gem gravel ('rai')Çraï) at PhnumPhnum Ko Ngoap. Rubies, sapphires and garnets are 68 Figure 5: View looking south to the low hill recovered fromfrom impersistent lenses of stickysticky 68 (middle distance) forming the vent of the PhnumPhnum yellow-brown clays (green-grey when freshlyfreshly Ko Ngoap basalt body.body. Further Further south south (in (in the the back back exposed) which are difficult to break down.down. ground) are the jungle-clad Tadeth MountainsMountains Photograph by E.A. Jobbins. (largely greywacke sedimentary rocks). In the foreground are gem dealers on motorcycles, who collect and market the gem material from the volcanicvolcanic belbeltt ooff easterneastern AustraliAustraliaa (Pain(Pain,, 19831983;; miners. Photograph by E.A. Jobbins. Johnson,Johnson, 1989).1989). ThisThis basalticbasaltic shielshieldd (Figure 1) 1) waswas eruptederupted througthroughh foldedfolded PalaeozoicPalaeozoic basemenbasementt anandd granitegranite rocks,rocks, mostlmostlyy betweenbetween 50-650-600 milliomillionn yearsyears (m.y.)(m.y) agoago,, althoughalthough episodicepisodic gem-bearingem-bearingg eruptioneruptionss continuedcontinued uupp ttoo 5 m.y.m.y. agoago (Sutherland(Sutherland et a/.,al., 19931993;; SutherlandSutherland andand Coenraads,Coenraads, 1996;1996; SutherlandSutherland andand Fanning,Fanning, 1996).1996). TheThe shielshieldd isis dominateddominated bbyy alkalialkali basaltbasaltss (O'Reilly(O'Reilly anandd ZhangZhang,, 19951995;; SutherlandSutherland anandd Fanning,Fanning, 1996).1996). ThThee oldestoldest NENE parpartt shedssheds alluvialalluvial corundumscorundums thatthat werewere studiedstudied fromfrom ththee GummiGummi area,area, whichwhich iiss draineddrained bbyy thethe upperupper ManninManningg River.River. AssociateAssociatedd zirconzirconss gavegave fissionfission tracktrack agesages ooff aroundaround 55 m.y.m.y. TheThe youngesyoungestt SESE partpart provideprovidess near-sourcnear-sourcee corundumscorundums thatthat werewere studiedstudied frofromm GloucesterGloucester TopsTops,, inin thethe headwaterheadwaterss ofof thethe KerripitKerripit andand GloucesterGloucester Rivers.Rivers. ZirconsZircons withwith thesethese corundumcorundumss yieldyield agesages asas youngyoung asas 4-54-5 m.y.m.y.
JJ. . Gemm., 1998,26,2,65--85 1998, 26, 2, 65-85 TheThe WesWestt PaiIinPailin materialmaterial fromfrom ththee PailinPailin basalbasaltt fieldfield (Figure 2) 2) came cam frome from the th Phnume Phnum Ko K o NgoaNgoapp basaltbasalt bodybody (E.A.J.(E.A.J, collectioncollection stationstation 29),29), fromfrom anan eluvial!eluvial/colluvia colluviall depositdeposit oonn thethe basaltbasalt marginmargin aboutabout 0.40.4 kmkm south-westsouth-west ofof thethe remnantremnant ventvent (Figures 3-5). 3-5). The Th egem-bearing gem-bearin g basaltsbasalts aroundaround PaiIinPailin andand adjacentadjacent easterneastern ThailandThailand werewere eruptederupted 1-41-4 MaMa agoago (Suttirat(Suttirat et a/.,al, 1994;1994; DavisDavis andand Barr,Barr, 1995).1995). TheThe WesWestt PailinPailin basaltbasaltss yieldyield corundumcorundum inin whicwhichh rubrubyy iiss predominantpredominant overover sapphiresapphire (about(about 70%70% rubyruby atat StationStation 29),29), somesome pyrope-almandinepyrope-almandine garnetgarnet andand littlelittle zirconzircon.. PhnurnPhnum KoKo NgoapNgoap materialmaterial isis dominateddominated byby palepale pinpinkk toto red,red, light-blue,light-blue, mauvemauve andand purplpurplee corundurns.corundums. InIn contrast,contrast, atat Figure 6: Scanning Electron MicroscopeMicroscope East Pailin sapphire predominates over ruby photomicrograph, showing showing corroded corroded surface surface of a of a East PaiIin sapphire predominates over ruby pink corundum grain from Gloucester Tops, (about 95%) and zircon is a common accessory pink corundum grain from Gloucester Tops, (about 95%) and zircon is a common accessory Barrington volcano. Note the strong etchingetching (Berrange(Berrangé andand Jobbins,Jobbins, 1976;1976; JobbinJobbinss andand leaving a criss-cross ridge-like surfacesurface Berrange,Berrangé, 1981).1981). PhnumPhnum YatYat materiamateriall isis morphology. Photograph Photograph by byG. AvernG. Avern and and B.J. B.J. dominateddominated bbyy colourlesscolourless toto pale-bluepale-blue ttoo blueblue Barron, Xl X100. 00. sapphires,sapphires, manymany withwith coloucolourr zoning.zoning. TheThe westernwestern ruby-bearinruby-bearingg basaltsbasalts lielie rangerange ofof colourscolours (Figure 7).7). There There areare twotwo alongalong a faultedfaulted olderolder crystallinecrystalline complexcomplex ooff distinctdistinct corundumcorundum suites,suites, eacheach witwithh differentdifferent metamorphosemetamorphosedd granodioritegranodiorite andand diorite,diorite, trace-elementtrace-element patterns.patterns. amphiboliticamphibolitic gneissesgneisses andand schists,schists, whereaswhereas OneOne suitesuite containscontains rubyruby andand sapphiresapphire thethe easterneastern sapphire-bearingsapphire-bearing basalbasaltt intrudesintrudes 69 69 ranginrangingg fromfrom colourlesscolourless toto pink,pink, mauve,mauve, youngeyoungerr rocksrocks alongalong a boundarboundaryy betweenbetween violetviolet,, blueblue,, blue-greeblue-greenn andand purplepurple withwith Devonian-CarboniferousDevonian-Carboniferous metasedimentarymetasedimentary crystalcrystal formsforms whichwhich havehave beenbeen andand volcanicvolcanic rocksrocks andand TriassicTriassic sedimentarysedimentary magmaticallmagmatic allyy roundedrounded withwith heavilheavilyy etchedetched bedsbeds (Figure 2).2). These These rocksrock s lieli e withinwithin thethe Indo-ChinaIndo-China TerraneTerrane (microcontinental(microcontinental block)block),, whicwhichh extendsextends westwest intointo ThailandThailand (Bunopas(Bunopas Figure 7: Corundums from Gloucester Tops,Tops, andand Vella,Vella, 1992).1992). TheThe WestWest PailinPailin suitessuites Barrington volcano,volcano, showing showing surface surface corrosion corrosion correlatecorrelate withwith ththee TraTratt ThailandThailand suitessuites featuresfeatures andand range range in incolours. colours. Photomicrograph Photomicrograph formingforming a 'ruby-rich''ruby-rich' area.area. FurtheFurtherr westwest by G. Webb,Webb, X15. X15. basaltsbasalts ofof south-easternsouth-eastern ThailandThailand lielie withinwithin thethe Shan-ThaiShan-Thai block,block, whichwhich includesincludes cratoniccratonic PrecambrianPrecambrian gneissgneiss (Bunopas(Bunopas andand Vella,Vella, 1992),1992), andand showshow a significantsignificant sapphiresapphire componentcomponent (see(see HughesHughes,, 1990,1990, Figure 11.19). 11.19). TheyThey correlatecorrelate moremore closelyclosely withwith ththee EastEast PailinPailin sapphiresapphire fields.fields.
MaterialsMaterials Barrington suites suites TheThe BarringtoBarringtonn corundumscorundums havehave beenbeen describeddescribed inin SutherlandSutherland et al., 19931993,, SutherlandSutherland andand Coenraads,Coenraads, 1996,1996, andand byby WebbWebb,, 1997.1997. TheThe crystalscrystals andand fragmentsfragments showshow surfacesurface etchingsetchings (Figure 6) 6) and and a awide wide
Distinctive gem corundum suites from discrete basalt fieldsfields Figure 8: Ruby series corundum crystalcrystal Figure 10: Pale pink and ruby corundumcorundum (mauve-pink) containing intergrowths ofof crystals fromfrom Phnum Ko Ngoap suite, sapphirine (blue-green) andand pleonastepleonaste spinel spinel both showing prominent intergrowths ofof (dark opaque), opaque), from from Gloucester Gloucester Tops, Tops, Barrington Barrington sapphirine (green). Photomicrograph by volcano. Photomicrograph Photomicrograph by G.by Webb,G. Webb, X25. X25. G. Webb, X20. X20.
exteriors.exteriors. CrystalsCrystals rangerange uupp toto 6 mmmm across:across: West PailinPailin suites suites chromiachromiann spinel,spinel, spinelspinel andand sapphirinesapphirine ThesThesee corundumscorundums (Figures 9 9and and 10) 10) are ar e occuoccurr asas inclusionsinclusions (Figure8), 8), and and crust-likecrust-like (Figure veryvery similarsimilar inin characteristiccharacteristicss toto thethe spinel reaction rims are preserved on some spinel reaction rims are preserved on some BarringtonBarrington suitessuites andand mamayy alsalsoo bbee grains. The other suite is typical of East grains. The other suite is typical of East consideredconsidered inin twtwoo groupsgroups ofof colours.colours. AustraliaAustraliann sapphiressapphires andand isis dominatedominatedd bbyy blue-greenblue-green,, euhedraleuhedral,, growth-zonedgrowth-zoned TheThe firstfirst grougroupp ofof PhnumPhnum KKoo NgoapNgoap sapphiresapphire,, oftenoften exhibitinexhibitingg corroded,corroded, corundumscorundums rangrangee frofromm 2 ttoo 9.9.5 mmmm acrosacrosss 70 70 broken-barrebroken-barrell habitshabits.. CrystalsCrystals areare generallygenerally andand varvaryy frofromm palpalee pinpinkk ttoo red,, lighlightt blueblue,, largelargerr thathann iinn ththee firsfirstt suitsuitee anandd rangrangee uupp ttoo mauvmauvee anandd purplepurple.. SomeSome shoshoww a coloucolourr 8 mmmm across.across. changchangee frofromm reredd shadesshades iinn incandescenincandescentt light ttoo blubluee shadeshadess iinn daylightdaylight.. PinPinkk anandd redred corundumscorundums fluorescfluorescee reredd undeunderr long-wavlong-wavee Figure 9: Corundums fromfrom Phnum Ko Ngoap ultravioletultraviolet,, thougthoughh leslesss intenselintenselyy thathann iinn suite, West Pailin, showing surface corrosioncorrosion equivalentequivalent BarringtoBarringtonn stonesstones.. TheTheyy araree inerinertt featuresfeatures and range in colours. Note intergrowthsintergrowths under short-wave ultraviolet. In habit, of sapphire and spinel and fusionfusion crusts on some under short-wave ultraviolet. In habit, corundums.corundums. Photomicrograph by G.G. Webb, X15X15.. crystalcrystalss araree magmaticallmagmaticallyy corrodecorrodedd andand rounded.. MineraMinerall inclusioninclusionss araree presenpresentt andand negativnegativee crystalcrystalss surroundesurroundedd bbyy decrepitatiodecrepitationn haloehaloess araree commoncommon,, somsomee witwithh two-phastwo-phasee inclusioninclusionss containincontainingg a gagass bubblebubble.. Liquid-filleLiquid-filledd fracturefracturess ofteoftenn exhibiexhibitt aa thin-filthin-filmm effeceffectt anandd sometimesometimess liliee acrosacrosss twinnintwinningg lamellaelamellae.. IroIronn oxide/hydroxideoxide/hydroxide staininstainingg iiss prevalentprevalent.. PolysynthetiPolysyntheticc twinnintwinningg iiss welwelll developedevelopedd anandd somsomee twinnintwinningg planeplaness shoshoww tube-liketube-like,, liquid-filleliquid-filledd fracturesfractures,, witwithh associateassociatedd mineralisationsmineralisations.. BoehmitBoehmitee needleneedless anandd crystallographically-controllecrystallographically-controlledd trellitrelliss patternpatternss araree presentpresent.. ThThee seconsecondd grougroupp ooff PhnuPhnumm KKoo NgoaNgoapp corundumcorundurnss containcontainss a rangrangee frofromm colourlescolourlesss ttoo palpalee blubluee anandd manmanyy shoshoww coloucolourr zoningzoning.. LikLikee BarringtoBarringtonn blubluee crystalscrystals,, theythey fallfall intointo twotwo
JJ.. Gemm.,Gemm., 1998,1998, 26,26, 2,2, 65-85 differentdifferent types.types. TheThe largerlarger typetype measuresmeasures upup toto bunches,bunches, likelike crystalcrystal axes,axes, fromfrom aa centralcentral 88 mmmm inin broken-barrelbroken-barrel shapedshaped crystalscrystals oror asas hexagonalhexagonal core;core; polysyntheticpolysynthetic twinningtwinning cross-sectionscross-sections alongalong partingparting planes.planes. FacesFaces areare lamellaelamellae areare evident.evident. TheThe secondsecond groupgroup ofof oftenoften stronglystrongly magmaticallymagmatically corrodedcorroded oror smallersmaller corundumscorundums areare aroundaround 2-32-3 mmmm across,across, slightlyslightly rounded.rounded. AmongAmong thethe inclusions,inclusions, silksilk isis lighterlighter inin colourcolour andand moremore transparent.transparent. presentpresent asas orientedoriented needles,needles, asas particlesparticles alongalong CrystalsCrystals areare magmaticallymagmatically roundedrounded andand hexagonalhexagonal growthgrowth zoneszones oror radiatingradiating inin etched,etched, withwith nono obviousobvious colourcolour zoningzoning oror silk.silk.
MethodMethodss o off analysi analysiss FieldsFields,, NSW)SW);; anandd 3300 'basaltic 'basaltic'' sapphiresapphiress (blue(blue,, greengreen,, green-bluegreen-blue,, yellowyellow,, partiparti Twenty-onTwenty-onee BarringtoBarringtonn corundumcorundumss colouredcoloured)) fro fromm Easter Easternn Australia Australiann minin miningg (CORBA(CORBARR 1-21 1-21)) an andd fourtee fourteenn Wes Westt Paili Pailinn fieldfieldss inin QueenslanQueenslandd anandd NeNeww SoutSouthh (Phnu(Phnumm KKoo Ngoapgoap)) corundumcorundumss WalesWales,, bu butt withou withoutt exac exactt localities localities.. (CORCA(COR CAMM 1-141-14)) werweree polishepolishedd anandd analyseanalysedd foforr tractracee elementelementss anandd colourcolour- ThThee elementelementss considereconsideredd usefuusefull inin absorptioabsorptionn spectraspectra.. Twenty-ninTwenty-ninee PailiPailinn characterisincharacterisingg ththee corundumcorundumss araree ironiron, , corundumcorundumss (Jobbin(Jobbinss 1-5) 1-5),, showinshowingg titaniumtitanium,, chromiumchromium,, galliumgallium,, anandd inclusionsinclusions,, intergrowthintergrowthss oorr fusiofusionn crustcrustss vanadiumvanadium,, an andd a a quantitativ quantitativee classificatio classificationn werweree selecte selectedd oonn th thee basi ba sis ooff microscop microscopee schemschemee fo forr thes thesee element elementss (a (ass wt wt%% oxides oxides)) studstudyy anandd polishepolishedd foforr electroelectronn hahass bee beenn establishe establishedd empirically empiricaUy:: microprobmicroprobee analysesanalyses.. OOff thesethese,, 1122 werweree analyseanalysedd fo forr majo majorr elemen elementt oxide oxidess an andd 9 9 LowLow MediumMedillm HighRigh DetectionDetection limit werweree analyse analysedd fo forr minominorr elemen elementt oxides oxides.. FeFep?0,, 3<0. <0.55 0.5-1.0.5-1.00 >1.>1.00 0.000.0055 ThThee pastel-coloure pastel-colouredd sapphire-rubsapphire-rubyy suitesuitess Ti0TIO2 <0.0<0.011 0.01-0.0O.D1-O.Q33 >0.0>0.033 0.000.0055 araree terme termedd fancy fancy colourscololll's or 'metamorph'metamorphic'ic' l GaGap0, 3<0.0 <0.011 0.01-0.00,01-0.033 >0.0>0.033 0.000.0055 typetype suites /lites anandd ththee blue-zoneblue-zonedd corundumcorundumss ? Crp3<0.0 <0.101 0.01-0.00.01-0.055 >0.>0.55 0.000.0055 1171 araree termetermedd 'basaltic''basaltic' typetype suitessuites inin ththee &A O,01-O.D3 >0.03 0.005 followinfollowingg descriptiondescriptionss (thes(thesee twtwoo VVPA 3 <0.0<0.101 0.01-0.03 >0.03 0.005 categoriecategoriess wit withh inferre inferredd differen djfferentt origin originss Electron microprobe analyses of araree basebasedd onon geochemicageochemicall comparisoncomparisonss Electron microprobe analyses of corwldums and associated mineral phases madmadee in in th thee Discussio Discussinon section) section).. corundums and associated mineral phases werweree mad madee usin usingg a nan automate automatedd CAMEC CAMECAA SX50 CAMEBAX electron-microprobe Chemical. Chemical data data SX50 CAMEBAX electron-microprobe witwithh a nan ED EDSS attachment attachment,, i nin th thee Material Materialss ChemicaChemicall analyse analysess wer weree obtaine obtainedd b yby a a SciencSciencee Faculty Faculty,, Universit Universityy o fof Ne wew Sout Southh semi-quantitativsemi-quantitativee EDXR EDXRFF method method, ,usin usingg a a WalesWales,, SydneySydney.. OperatinOperatingg conditionconditionss SpectracSpectracee 500 50000 EDXR EDXRFF syste systemm (Stern (Stem,, 1984) 1984).. includeincludedd a nan acceleratin acceleratingg voltag voltagee o fof 1 155 kV kV,, aa AA totatotall ofof 161622 samplesampless werweree testetestedd samplsamplee curren currentt o fof 2 020 nA nA,, PAPPAPSS softwarsoftwaree comprisingcomprising:: foforr processinprocessingg raraww countcountss anandd aann ASTIMEX standard block. 2121 BarringtonBarrington,, 1414 CambodiaCambodiann anandd ASTIMEX standard block. 9 corundums from West PaBin (E.A. 9 corundums from West Pailin (E.A. Spectroscopic data Jobbins)Jobbins);; 6161 blubluee 'basaltic'basaltic'' sapphiresapphiress Spectroscopic data Ultraviolet-visible-near infrared (UV-vis (varyin(varyingg hu huee an andd colou colourr intensity intensity)) frofromm Ultraviolet-visible-near infrared (UV-vis- NlR, 280 to 880 nm) spectra were run on a 'Pailin'Pailin'' (probabl (probablyy Eas Eastt Paili Pallinn minin miningg area) area);; NIR, 280 to 880 nm) spectra were run on a Perkin Elmer Lambda 9 spectrophotometer 1818 'basaltic 'basaltic'' sapphire sapphiress (blue (blue,, green green,, yellow yellow- Perkin Elmer Lambda 9 spectrophotometer brown, parti-coloured; including a green at the Giibelin Laboratory. Although brown, parti-coloured; including a green at the Gübelin Laboratory. Although and a blue star sapphire) from the Anakie ordinary ray (0) and extraordinary ray (e) and a blue star sapphire) from the Anakie ordinary ray (o) and extraordinary ray (e) Fields in Central Queensland (Tomahawk spectra were recorded where possible, the Fields in Central Queensland (Tomahawk Creek, Willows, Rubyvale); 9 'basaltic' spectrsize aand wer eshape recorde ofd mostwher eBarrington possible, thande Creek, Willows, Rubyvale); 9 'basaltic' sapphires (blue, dark green-blue, yellow sizCambodiane and shap samplese of mos precludedt Barringto registrationn and sapphires (blue, dark green-blue, yellow- brown) from Inverell (New England Cambodiaof polarisedn sample spectras .preclude d registration brown) from Inverell (New England of polarised spectra.
Distinctive gemgem corundumcorundum suitessuites fromfrom discretediscrete basaltbasalt fieldsfields Table I: I: Trace-element Trace-element ranges ranges in corundums in corundums from Australia.from Australia.
BarringtonBarrington COrtl11d1l1tl corundum range range Typical Allstralian Australian 'basaltic''basaltic' s apphirsapphireses 'metamorphic''metamorphic' 'basaltic''basaltic' 'basaltic''basaltic' (Fe,Ti(Fe, Ti rich) rich) ColourColollr bluebille violet-blueviolet-blue purple-redpurple-red bluebille blue blue, greell,green, y eyellow,llow, parti-colouredparti-cololl red WtWt%% 11 0.0-0.5 (0.14) Z2 Ti0TiO2z 0.02-O.050.02-0.05 0.04-0.00.04-0.099 0.0-0.00.0-0.066 0-0.00-0.044 -0.-0.11 0.0-0.5 (0.14) V 0 v22o5S <0.0<0.011 0.01-0.00.01-0.044 <0.0<0.011 <0.0<0.011 <0.00<0.0055 <0.00<0.0055 Cr 0 0.01-0.04 0.05-0.02 0.1-0.4 0.005 <0.005 <0.005 Cr22Os3 0.01-0.04 0.05-0.02 0.1-0.4 0.005 <0.005 <0.005 0.6-1.0 0.5-1.2 0.4-0.6 0.7- 1.6 -2 0.7- 1.8 FeFep2Os3 0.6-1.0 0.5-1.2 0.4-0.6 0.7-1.6 -2 0.7-1.8 Gap3 <0.01 <0.01 <0.01 0.02-0.04 -0.02 0.015-0.04 Ga2Os <0.01 <0.01 <0.01 0.02-0.04 -0.02 0.015-0.04 SampleSampless CORBAR33 CORBAR 1,2,5,1,2,5,66 3,4,10,153,4,10,15,, 7,8,9,17,8,9,199 11,13,14,211 ,13,14,211 1122 5757 (se(seee textextt foforr 16,17,18,216,17,18,200 explanationexplanation)) Spectral 'Fe(+Cr)' 'metamorphic' 'Cr(+Fe)' 'basaltic'7 'ba alHc' 'basaltic' Spectra4 l Te(+Cr)' 'metamorphi'Cr+Fe' c ' 'Cr(+Fe)' 'basaltic 'basaltic' 'basaltic' typetype4 'Cr+Fe' Notes:Notes: 1.1. ResultsResults obtainedobtained bbyy EDXREDXRFF 2.2. BlueBlue star-sapphirstar-sapphiree fromfrom Anakie,Anakie, NSNSWW 3.3. CORBARCORBAR symbolisessymbolises corundumscorundums frofromm BarringtonBarrington 72 72 4.4. SeeSee textextt foforr detailsdetails
Table II:II: Trace-elementTrace-element range range for Westfor West Pailin Pailin corundums corundums ('metamorphic' ('metamorphic' type, 'basaltic' type, 'basaltic' type, and type,FelTi-rich and Fe/Ti-rich 'basaltic''basaltic' type), type), compared compared to 'basaltic' to 'basaltic' type sapphirestype sapphires from East from Pailin. East Pailin. WestWest PailinPailill EastEast Pailin
'metamorphic''metamorphic' 'basaltic''basaltic' Fe/Ti-richFe/Ti-rich 'basaltic''basaltic' 'basaltic''basaltic' type type wt%Wt% BlueBlue Violet-blueViolet-blue PurplPurple-red/rede-red/red
TiOTI0z2 -0.-0.11 0.04-0.00.04-0.088 0.01-0.00.01-0.055 0.01-0.0O.Q1-O.o22 0.01-0.00.01-0.022 <0.0<0.011
vVP2o5 s -0.0-0.011 -0.0-0.011 <0.0<0.011 <0.00<0.0055 <0.00<0.0055 <0.0<0.011
CrCr2OZ0a 3 -0.0- 0.044 0.1-0.0.1-0.22 0.1-0.0.1-0.77 <0.00<0.0055 <0.00<0.0055 <0.005<0.005** F*FeZA0 3 --11 0.7-1.0.7-1.00 0.4-0. 0.4-0.99 0.3-1.0.3-1.11 --22 0.3-0.0.3-0.88 Ga 0 <0.01 <0.01 <0.01 0.02-.03 -0.04 0.02-0.04 Ga2203 3 <0.01 <0.01 <0.01 0.02-.03 -0.04 0.02-0.04 SampleSampless 2,4-10, 1,11,14 CORCAM 33 6611 blubluee sapphiresapphiress CORCAM 2,4-1012,13,15, 1,11,14 of different hues 12,13,15 of different hues Jobbins 3-2,3-4 Jobbins5 3-1 anandd coloucolourr Jobbins 3-2,3-to 3-94 Jobbins 5 3-1 intensities to 3-9 intensities Spectral type+ 'metamorphic' 'basaltic' 'basaltic' 'basaltic' Spectral type+ 'metamorphic' 'basaltic' 'basaltic' 'basaltic'
+see+see texttext forfor detailsdetails
J./. Gemm., 1998, 1998,26, 26, 2, 2, 65-85 65-85 1000.00 1000.00 Corundum, East Australia a Corundum, Pailin Cambodia b . .. 100.00- 100.00 .' ...... :- . 3' .. ~' 10.00- 10.00 () --...q ~ 1.00- 1.00
~DO o DB ell 0.10- • ~CJ DDDa~c~ 0.10 o~oll 0 0 Ca ; o D
O.OJ O.OJ 1.00 10.00 ·' 00.00 1000.00 1.00 10.00 100.00 1000.00
(Fe2OJ /Ti02) (PeP3/Ti02)
1000.00 1000.00 Corundum, East Australia C Corundum, Pa il in Cambodia d
100.00 100.00 73 73
~ 10.00 - 10.00 , : .. 0.01 I I 0.01 1.00 10.00 100.00 1000.00 1.00 10.00 100.00 1000.00 (Fe20 3/ CrP J) (Fe20 3/CrP3) Figure 11: Chemical variation diagrams showing wt% plots of trace-elementtrace-element contents of corundumscorundums fromfrom East Australia (Barrington and other gemfields,gemfields , a and c, and fromfrom Pailin,Pailin , Cambodia, bband and dd.. (a) CrCrp3/Gap203/Ga203 ) vs FeFep3/Ti0203/Ti02; 2; Barrington 'metamorphk''metamorphic' typetype (A);(.~) ; Barrington 'basaltic''basaltic' type (e)(•), East Australian 'basaltic''basaltic ' typetype (•)(0);; Barrington high 'Fe, Ti type'type ' (.).(M). (b) CrCrp203/GaJGap203 3 vs FeFep203/Ti03/Ti02; 2; West PailinPailin 'metamorphk''metamorphic' typetype (A);(A) ; West PßilinP.ailin 'basaltic''basaltic' type (e)(•); WestWest Pailin high 'Fe,'Fe, Ti type' (M);(.) ; East Pailin 'basaltic'~basaltic' typetype (0).(Q). (c) Ti0 /Ga 0 vs Fe 0 /Cr 0 ; ; Barrington and other East Australian corundums. Symbols as in TiO2 z/Ga2 Z30 3 vs Fe2z03 3/Cr2 z30 3 Barrington and other East Australian corundums. Symbols as in FigureFigure lla.11a. (d) Ti0Ti0zlGap32/Ga203 vs FeFep3/Crp3;203/Cr203; West Pailin and East Pailin corundums. Symbols as inin Figure llb.lib. DistinctiveDistinctive gemgem corundumcorundum suitessuites fromfrom discretediscrete basaltbasalt fieldsfie lds ResultsResults InIn 'metamorphic''metamorphic' PailinPailin corundums,corundums, however,however, valuesvalues reachreach uupp toto 1% Fe 00 .. AAnn Trace and minor element contents of 22 3 Trace and minor element contents of Fe/Ti-richFe/Ti-rich 'basaltic''basaltic' typetype sapphirsapphiree fromfrom corundums, that correlate with the absorp corundums, that correlate with the absorp WestWest PaiIinPailin containscontains aboutabout 22%% Fe 0O .. tiotionn spectra,spectra, areare summarisedsummarised inin Table II 22 3s (Barrington(Barrington 'metamorphic''metamorphic' typetype andand TheThe Fe-contentFe-content isis a goodgood 'separation'separation 'basaltic''basaltic' typetype comparedcompared ttoo typicaltypical criterion'criterion' forfor 'basaltic''basaltic' corundumscorundums fromfrom AustraliaAustraliann 'basaltic''basaltic' typtypee sapphiressapphires fromfrom EastEast AustralianAustralian andand PailinPailin mininminingg fields:fields: QueenslandQueensland andand NeNeww SouthSouth WalesWales miningmining mostmost 'basaltic''basaltic' PailinPailin corundums containcontain fields),fields), Table II II (West (Wes t PailinPailin 'metamorphic''metamorphic ' lessless thanthan 0.5%0.5% FeFep3'203. OnOn ththee otheotherr hand,hand, corundumscorundums comparedcompared ttoo 'basaltic''basaltic' typetype typicaltypical Fe-concentrationsFe-concentrations iinn 'basaltic''basaltic' sapphiressapphires fromfrom EastEast Pailin)Pailin) andand inin corundumscorundums fromfrom EastEast AustraliaAustralia Figure lla-d.lla-d. MajorMajor elementelement valuesvalues forfor (Barrington,(Barrington, Inverell,Inverell, Anakie)Anakie) exceedexceed 1%% Fe 0 . Less than 10% of the 161 corundums corundumcorundumss andand co-existingco-existing mineralsminerals areare Fe2203. Less than 10% of the 161 corundums summarisedsummarised inin Tables IIIA and HIBIIIB andand examinedexamined herehere fallfall intointo ththee over-lappingover-lapping Figure 12. 12. SelectedSelected UV-vis-NIRUV-vis-NIR absorptionabsorption 'corridor''corridor' betweenbetween 0.60.6 andand 1.0%1.0% FeFep3'203. A spectraspectra forfor EastEast AustraliaAustraliann andand PailinPailin separationseparation ofof thethe 'metamorphic''metamorphic' corundumscorundums areare presentedpresented inin Figures 13-15. 13-15. corundumscorundums fromfrom EasEastt AustraliaAustralia anandd PailinPaiIin,, using Fe,Fe, IiTi concentrations,concentrations, however,however, isis notnot possible.possible. AsAs Figure 11 11 shows, shows there, ther eis inears nea r Corundum chemistry chemistry completecomplete overlapoverlap forfor thesethese corundums.corundums. BothBoth BarringtonBarrington andand WestWest PailinPailin 2.2. TitaniumTitanium corundumscorundums havehave comparablecomparable trace-elementtrace-element contentscontents (Figure 11) 11) and an dessentially essentiall yfall fal intol int o2 2 ManyMany EastEast AustralianAustralian 'basaltic''basaltic' sapphiressapphires ). distinctdistinct groups.groups. TheThe fancyfancy colouredcoloured 'meta'meta showshow onlyonly negligiblenegligible IiTi (<0.005«0.005%% Ti02). morphicmorphic'' typetype suitessuites areare characterisedcharacterised byby lowlow Some,Some, however,however, maymay containcontain uupp ttoo 0.050.05%% 74 74 Gap3Ga203 «0.01(<0.01 wt%)wt%) andand bbyy highhigh CrpiGap3Cr203/Ga203 Ti02 (compare(compare Tables lA, I A, B), B) and, an thed th Fe,e Fe and, an d ratioratioss (mostly(mostly betweebetweenn 1010 andand 100).100). TheThe Ti-richTi-rich 'basaltic''basaltic' corundumcorundum fromfrom 'basaltic' type sapphires show higher Ga 0 BarringtonBarrington containscontains aboutabout 0.1 % Ti0Ii02.. ThThee 'basaltic' type sapphires show higher Ga220 3 2 (0.015-0.040(0.015-0.040 wt%)wt%) witwithh CrpiGap3Cr203/Ga203 alwaysalways highesthighest Ti-contentTi-content ofof 0.14%0.14% Ti02 wawass foundfound belowbelow 1.1. TheseThese twtwoo chemicachemicall groupsgroups inin a blueblue starstar sapphiresapphire fromfrom AnakieAnakie.. ThThee correlatecorrelate withwith twtwoo differentdifferent patternspatterns moremore usualusual 'basaltic''basaltic' sapphiressapphires fromfrom observedobserved amongamong thethe colour-absorptioncolour-absorption BarringtonBarrington fallfall intointo thethe concentrationconcentration rangerange spectra,spectra, discusseddiscussed belowbelow.. TheiTheirr chemistrychemistry inin ofof sapphiressapphires fromfrom AnakieAnakie anandd NewNew comparisoncomparison toto corundumscorundums fromfrom otherother areasareas England.England. ManyMany 'metamorphic''metamorphic' BarringtonBarrington provideprovidess thethe followingfollowing resultsresults:: corundumscorundums havehave Ti-contentsTi-contents oveoverr 0.040.04%% Ti0 , withwith maximummaximum valuesvalues uupp ttoo 0.090.09%% 1.1. IronIron 2 Ti02.. TheThe Ti-concentrationTi-concentration iinn WesWestt PailiPailinn TheThe Fe-Fe- andand Ti-concentrationsTi-concentrations ofof EastEast 'metamorphic''metamorphic' corundumscorundums rangerangess fromfrom AustralianAustralian sapphiressapphires showshow somesome variationvariation , 0.010.01 toto aboutabout 0.1%0.1% Ti02, whilwhilee fourfour (Table I) I)with wit hnormally normall y0.4 0. 4and an d1.8% 1.8% Fep3' Fe203 , 'basaltic''basaltic' sapphiressapphires fromfrom WesWestt PailinPailin reachingreaching upup toto aboutabout 2%2% Fep3Fe203 inin a Fe/TiFe/Ti- containcontain onlyonly om0.01 toto 0.02%0.02% Ti02.. TheThe FeFe- richrich 'basaltic''basaltic' typetype corundumcorundum fromfrom 2 andand Ii-richTi-rich typetype hashas 0.1-0.2%0.1-0.2% Ii0Ti02.• ManyMany Barrington. Most 'metamorphic' 2 Barrington. Most 'metamorphic' 'basaltic''basaltic' sapphiressapphires fromfrom EastEast PailiPailinn areare Barrington corundums lie between 0.4 and Barrington corundums lie between 0.4 and almostalmost Ti-free,Ti-free, whilewhile maximummaximum contentcontentss liliee 1.2%1.2% Fe 2003. TheThe 'basaltic''basaltic' corundurnscorundums fromfrom 2 3 aroundaround 0.07%0.07% Ti02 (Table II). II). thethe AnakieAnakie andand NeNeww EnglanEnglandd fieldsfields rangerange 2 3.3. GalliumGallium fromfrom 0.70.7 toto 1.8%1.8% FeFep3'203. TheThe 'basaltic''basaltic' corundumscorundums fromfrom thethe PailiPallinn miningmining areaarea GalliumGallium inin particularparticular delineatesdelineates twotwo showshow a smallersmaller variationvariation thanthan inin EastEast 'types''types' ofof corundumcorundum suitessuites forfor AustralianAustralian samplessamples (Table II). II). Over Ove r90% 90% of o f EastEast AustraliaAustralia andand Pailin,Pailin, withwith thethe 'basaltic''basaltic' PailinPailin corundumscorundums occupyoccupy a pronouncedpronounced differencesdifferences iinn theirtheir narrow range between 0.3 and 0.7% Fe 0 . narrow range between 0.3 and 0.7% Fe220 3. mineralogicaIlmineralogical/ chemicalchemical features.features. J./. Gemm., 1998, 26,2,26, 2, 65-8565-85 'Basaltic''Basaltic' corundumscorundums havehave highhigh GaGa- Figure lla,11a, b. TheseThese diagramsdiagrams showshow thethe ratiosratios contentscontents (0.015(0.015 ttoo 0.040%0.040% Ga2003)),, whereaswhereas (Cr220033/Gap3)/Ga203) vsvs (Fep/Ti0(Fe203/Ti022)) andand areare anan GaGa concentrationsconcentrations forfor thethe 'metamorphic''metamorphic' excellentexcellent tootooll toto distinguishdistinguish twotwo gemgem corundumscorundums areare lowlow «0.01%(<0.01% Ga22003; corundumcorundum suitessuites inin thesethese basalticbasaltic fields.fields. TheThe comparecompare Tables II and and II).II). metamorphicmetamorphic corundumcorundum fieldfield characterisedcharacterised byby 4.4. Chromium highhigh Crp3/Ga203Cr203/Ga203 ratiosratios (mostly(mostly betweenbetween 1010 andand 100)100) isis clearlyclearly separateseparate fromfrom thethe basalticbasaltic ChromiuChromiumm concentrations,concentrations, likelike gallium,gallium, corundumcorundum fieldfield forfor whichwhich Cr 00 /Gap3/Ga 0 isis alsoalso differdiffer inin thethe basaltibasalticc andand 22 3 2 3 alwaysalways <1.<1. TheThe Fe/Ti-ratioFe/Ti-ratio isis notnot diagnosticdiagnostic forfor 'metamorphic''metamorphic' corundums.corundums. separatingseparating thesthesee types,types, becausebecause ofof theirtheir TheThe 'basaltic''basaltic' corundumscorundums fromfrom practicallypractically identicalidentical widthwidth ofof variation.variation. EastEast AustraliAustraliaa analysedanalysed herehere areare yellow,yellow, TheThe fieldsfields forfor thethe twotwo 'metamorphic''metamorphic' green,green, oror blueblue,, whilwhilee thosethose fromfrom PailinPailin areare suitessuites fromfrom PailinPailin andand BarringtonBarrington areare almostalmost allall blubluee witwithh differentdifferent huehuess andand identical.identical. ForFor basalticbasaltic fieldsfields fromfrom intensities.intensities. Gemmologically,Gemmologically, thetheyy areare EastEast AustraliaAustralia andand Pailin,Pailin, thethe 'areas'areas ofof consideredconsidered asas Fe-Fe- andand Ti-colouredTi-coloured highesthighest density'density' areare different:different: PailinPailin mostlymostly sapphires.sapphires. TheThe chromiumchromium contentscontents ofof has Fe 0 /Ti0 ratios below 100 has Fe220 3/Ti022 ratios below 100 thesethese sapphiressapphires areare belowbelow thethe detectiondetection (see Figure 11b),lib), whereaswhereas EastEast AustralianAustralian limitlimit forfor thethe analyticalanalytical methodmethod (about(about ratiosratios areare mostlymostly overover 100100 (Figure 11a). ThisThis 0.005%0.005% Cr2003)).. TheThe 'metamorphic''metamorphic' stemsstems fromfrom 'typical''typical' Fe-contentsFe-contents inin EasternEastern EastEast AustralianAustralian andand PailinPailin corundumscorundums AustralianAustralian sapphiressapphires exceedingexceeding thosethose forfor show a quite distinctive range of colours: show a quite distinctive range of colours: PailinPailin sapphiressapphires (Table II). II). pink,pink, redred,, mauvemauve,, violet,violet, purplepurple andand blue,blue, TheThe representativerepresentative pointspoints forfor 'normal''normal' whicwhichh cancan bbee consideredconsidered inin threthreee groupsgroups basalticbasaltic corundumscorundums fromfrom BarringtoBarringtonn andand asas blubluee sapphires,sapphires, fancyfancy colourcolour sapphiressapphires WestWest PailinPailin allall liliee inin thethe fieldsfields forfor sapphiressapphires andand rubiesrubies.. ChromiumChromium isis presenpresentt inin allall fromfrom otherother EastEast AustralianAustralian (Anakie,(Anakie, NewNew 75 'metamorphic''metamorphic' BarringtonBarrington andand PailinPailin 75 England)England) andand EastEast PailinPailin sapphiresapphire fields.fields. corundums,corundums, includingincluding blubluee oror greenishgreenish- blubluee varietiesvarieties,, andand contentcontentss rangrangee uupp 0.50.5%% TheThe Ti022/Gap3/Ga203 vsvs Fe220033/Crp3/Cr203 diagramsdiagrams Cr 0 . Intensely coloured crystals may (Figures 11e,lie, d) alsoalso clearlyclearly separateseparate Cr20 3 . Intensely coloured crystals may containcontain moremore;; thethe highesthighest analysedanalysed 'metamorphic''metamorphic' andand 'basaltic''basaltic' corundumcorundum suites.suites. content of 0.75% Cr 0 was found in a TheThe Fe 2003/Cr2003 ratioratio forfor metamorphicmetamorphic content of 0.75% Cr20 3 was found in a 2 3 2 3 PailinPailin ruby.ruby. TheThe highesthighest Cr-contentCr-content foundfound corundumscorundums fromfrom EastEast AustralianAustralian andand PailinPailin inin a BarringtoBarringtonn rubyruby inin thisthis studystudy waswas mostlymostly rangesranges betweenbetween 1 andand 1010 (extending(extending upup 0.4% Cr 0 , although 1.4 wt% Cr 0 has toto 5050 forfor BarringtonBarrington corundums).corundums). TheThe ratiosratios forfor 0.4% Cr20 3, although 1.4 wt% Crp32 3 has beenbeen recordedrecorded previouslpreviouslyy (Sutherland(Sutherland et al.,ah, 'basaltic''basaltic' sapphiressapphires areare muchmuch higher:higher: mostlymostly 1993).1993). 100-200100-200 forfor thethe blubluee sapphiressapphires fromfrom EastEast Pailin,Pailin, andand 300--600300-600 forfor thethe yellow,yellow, green,green, blueblue 5.5. VanadiumVanadium andand parti-coloureparti-colouredd sapphiressapphires fromfrom EastEast TheThe vanadiumvanadium contentscontents inin corundumscorundums Australia.Australia. WhereasWhereas typicaltypical Ti022/Ga2003 ratiosratios fromfrom EastEast AustraliaAustralia andand PailinPailin generallygenerally forfor 'basaltic''basaltic' sapphiressapphires fromfrom EastEast AustraliaAustralia andand lielie belowbelow ththee detectiondetection limitlimit ofof thethe EDXRFEDXRF PailinPailin areare lessless thathann 1,1, forfor thethe vastvast majoritymajority ooff analyticalanalytical methomethodd (about(about 0.005%0.005% Vps)'V205), thethe membersmembers ofof ththee 'metamorphic''metamorphic' suitesuite thethe butbut rarelrarelyy V20OSs maymay attainattain 0.010.01% %.. InIn thethe ratioratio rangesranges fromfrom 1 toto 1010.. 'metamorphic''metamorphic' corundums,corundums, thethe rangrangee ofof A fewfew 'basaltic''basaltic' sapphiressapphires fromfrom content is wider and reaches 0.015% V O content is wider and reaches 0.015% V20 Ss BarringtonBarrington andand WestWest PailinPailin showshow unusuallyunusually forfor PailinPailin andand 0.04%0.04% V20Os forfor BarringtonBarrington 2 S highhigh Fe-Fe- andand Ti-contentsTi-contents (2%(2% Fe20O3s andand purplpurplee sapphires.sapphires. 0.1-0.2%0.1-0.2% Ti02)),, beyonbeyondd thethe Fep3/Crp3Fe203/Cr203 A moremore completecomplete chemicalchemical characterisationcharacterisation rangerange ofof 'normal'normal basaltic'basaltic' corundumscorundums ofof 'basaltic''basaltic' andand 'metamorphic''metamorphic' corundumscorundums (Figures 11e,lie, d). ItIt isis uncertainuncertain whetherwhether thesethese fromfrom Pailin,Pailin, Cambodia,Cambodia, andand EastEast AustraliaAustralia isis corundumscorundums represenrepresentt anotheranother corundumcorundum- basebasedd onon thethe correlationcorrelation diagramdiagramss shownshown inin type,type, oror areare fragmentsfragments ofof largerlarger colour-zonedcolour-zoned Distinctive gem corundum suites from discrete basalt fieldsfields Table iliA: II I A: Representative Representative analyses analyses of cOTundums of corundums and some and primary some primary inclusions inclusions from West from Pailin. West Pailin. MineralMineral CorundumCOr/llldllm CorundumCOr/lndum PleonastePleonaste SapphirinSapphirinee FasFassaitesaite HHercyniteerctJnite (pink)(pink) (blue) (blue) sspinelpinel (11.13.5(11.13.5)) pyropyroxenexene sspinelpinel TypeType 'metamorphic''metamorphic' 'basaltic''basaltic' ''metamorphic'metamorphic' ''metamorphic'metamorphic' ''metamorphic'metamorphic' ''basaltic'basaltic' Wt%Wt % Si022 0.00.033 - 0.00.022 1313.8.811 48.8648.86 00.0.033 TÏ0Ti022 0.00.011 0.00.044 0.010.01 0.040.04 00.1.199 0.260.26 A1AIP203 98.198.144 100.2100.200 66.666.600 62.3162.31 1313.6.666 6363.0.000 Cr20 3 0.20.200 - 0.70.733 0.470.47 0.110.11 0.290.29 NiiOO 0.00.000 0.00.033 0.00.099 00.4.411 00.1.122 00.0.077 FeO 0.70 0.64 10.68 3.44 2.43 21 .77 FeOtololt 0.70 0.64 10.68 3.44 2.43 21.77 MnMnOO 0.00.033 - 0.10.100 00.0.022 0.030.03 00.1.155 MgMgOO 0.00.044 - 17.4717.47 19.5519.55 12.0912.09 13.5013.50 CaCaOO 0.00.022 - - 0.070.07 21.121.188 - ap - - - 0.02 1.54 - Na20 - - - 0.02 1.54 - Kfi~O -- 0.00.022 0.00.011 - - - Total Total 99.199.177 100.9100.933 98.998.999 100.5100.544 100.21100.21 9999.0.077 Samples Samples JoJobb 1.1.11 JoJobb 3.3.4 JoJobb 4.4.33 JoJobb 4.4.33 JoJobb 3.33.3 JobJob 3.103.10 FeO = totatotall iroironn oxidesoxides expresseexpressedd asas FeFeOO 76 76 tottot Table 1118: NIB: Representati Representativeve analyses analyses of reaction, of reaction, exsolution exsolution and alteration and alteration minerals inminerals corundum ins corundums from West Pailin. from West Pailin. OxideOxide ReactionReactioll ReactionReaction ReactionReaction ExsolutionEX50lutioll AlterationAlteratioll AlterationAlteration spinelspillel 1l spinelspinel 2 spinelspinel 3 spinelspinel 4 FeFe hydroxidhydroxidee chloritechlorite Wt%Wt % Si0Si02 2 0.00.066 - 0.00.011 0.00.044 - 28.328.333 Ti0Ti02 2 0.00.066 0.10.155 24.224.244 0.40.466 0.00.077 1.01.077 A1A40203 3 67.467.444 63.163.155 6.66.699 36.536.599 3.23.255 24.724.755 Cr 0 0.10.188 0.00.055 0.3 0.300 0.00.044 0.40.444 Cr2203 3 - NiOiO 0.20.233 - 0.10.133 0.00.088 0.00.055 0.00.022 FeO 8.38 22.70 60.99 53.60 84.36 31 .54 FeOtololt 8.38 22.70 60.99 53.60 84.36 31.54 MnMnOO 0.10.188 0.2 0.266 0.50.599 0.20.211 0.00.011 0.00.044 MgMgOO 21.521.577 12.212.288 3.23.211 6.06.066 0.00.055 0.20.233 CaCaOO 0.00.011 0.00.033 - - - 0.10.188 ap 0.03 0.1 4 Na20 - - 0.03 - - 0.14 Kp 0.02 0.14 Kp - - - - 0.02 0.14 Total 98.11 98.57 96.94 97.34 87.85 86.88 Total 98.11 98.57 96.94 97.34 87.85 86.88 Samples Job 2.5 Job 3.4 Job 3.4 Job 1.1 Job 1.1 Job 2.1 Samples Job 2.5 Job 3.4 Job 3.4 Job 1.1 Job 1.1 Job 2.1 SpineSpinel!:l 1: ReactioReactionn ririmm oonn sapphirinesapphirine.. SpineSpinell 22:: ReactioReactionn rim oonn blubluee corundumcorundum.. SpineSpinell 33:: ReactioReactionn phasphasee iinn spinespinell 22.. SpineSpinell 44:: ExsolutioExsolutionn lamellalamellaee iinn pleonastepleonaste.. -- meanmeanss belobeloww detectiodetectionn JJ.. Gemtn.,Gemm., 1998 1998,26,, 26, 2 ,2, 65--85 65-85 Si0 2 Si02mole % ~ 35~ ' 25 _ 0( '-Z__----> MgO+FeO AIP2+FeP3 40 ..I. 2.2.1 20 (0 p 45 MgO+FeO 45 50 AlpztFeP3 mole % mole % 77 , Figure 12: Mole% MgO+FeO, Alz03+Fez0 3 SiOz chemical variation diagram, showing relationship of Barrington (B) and West Pailin (P) corundum-hosted sapphirine compositions, in relation to the sapphirine composition reference line (including 2.2.1 and 7.9.3 member compositions). Thailand (Rubywell Mine) alluvial sapphirines (T) and NSW granulite-hosted sapphirine from lower crustal xenolith, Delegate (0) are plotted for comparison, based on diagram after Sutherland and Coenraads, 1996, Figure 4. crystals. Crystals with colour zoning and are slightly more Al-rich and Fe-poor than unusually high element concentrations spinels from the Barrington field (cfSp 68-73 related to certain zones have been found He 26-29 Cm 0-3 in Sutherland and from other localities (Schwarz, in prep.). Coenraads, 1996). In the 'basaltic' type corundums, spinels are more Fe-rich, but Mineral inclusions andintergrowths West Pailin compositions are less so than at Despite their geographical separation, Barrington. They are spinel-hercynite (Sp 53 Barrington and West Pailin corundums Hc 45 Usp 1 Mt 1; analysis in Table IIIA), rather than hercynite-magnetite (He 51-73, include minerals of very similar Mt 18-35, Mf 6-8 Usp 2-5) reported in compositions. Analyses of Pailin corundums and their primary inclusions (Table IIIA) are Sutherland and Coenraads, 1996. listed with those for alteration minerals (Table IIIB). Primary sapphirine is near a Absorption spectroscopy 11(MgO + FeO): 13(AIP3 + Fep3): 5SiOz The most important minor elements in mole % composition and approaches the corundums from East Australia and Pailin 7: 9 :3 composition of sapphirine inclusions are Fe, Ti, Cr, Ga, and V and of these, Fe, Ti, in Barrington fancy coloured corundums and Cr are significant in colour-causing (Figure 12). West Pailin spinels (Sp 78 Hc 22) processes (the V-concentration is generally Distinctive gemcorundum suitesfrom discrete basalt fields a b 78 78 c 400 600 800 nm Figure 13: Comparative colour absorption spectra related to Cr-bearing corundums.corundums. (a) Cr3+Cr3+ absorptionabsorption spectrumspectrum withwith intenseintense bandsbands aroundaround 400400 andand 550550 nmnm inin aa metamorphicmetamorphic corundumcorundum (ruby) from Mogok, Burma. Such 'pure' Cr-spectra havehave notnot beenbeen observed observed in in corundums corundums from from East East Australian and Pailin basaltic gemfields. (b) Representative absorption spectrum for ruby from basaltic fields,fields, Thai-Cambodian border region.region. InIn addition to the two broad Cr3+Cr3+ bands, bands, a a pronouncedpronounced 'shoulder''shoulder' inin thethe UVUV regionregion around around 330330 nmnm isis present. (c) The 'Thai ruby-type' absorption spectrum observed in 'metamorphic''metamorphic' type suites fromfrom Barrington and West Pailin basalts. J. Gemm., 1998,1998,26,2, 26, 2, 65-8565-85 tootoo lowlow toto actact asas colourcolour agent).agent). ChromiumChromium isis Barrington.Barrington. AbsorptionAbsorption spectraspectra ooff greengreen andand thethe dominantdominant chromophorechromophore inin pinkpink andand redred yellowyellow 'basaltic''basaltic' sapphiressapphires fromfrom EastEast corundumscorundums (rubies).(rubies). TheThe 'pure''pure' CrCr- AustraliaAustralia areare comparedcompared iinn Figures 14c and absorptionabsorption spectrumspectrum showshownn inin Figure 13a isis 14d. TheThe 'high'high FeFe,, Ti'Ti' 'basaltic''basaltic' sapphiressapphires characterisedcharacterised byby twotwo intensintensee bandsbands aroundaround presenpresentt absorptionabsorption spectraspectra markemarkedd byby a 400400 anandd 550550 nmnm butbut suchsuch spectraspectra araree notnot relativelyrelatively intenseintense Fe22++--Ti Ti4+4+ absorptionabsorption observedobserved inin thethe red/pinkred/pink corundumscorundums fromfrom (Figure 14e). BarringtonBarrington andand PailinPailin.. InsteadInstead,, theythey shoshoww a TheThe absorptionabsorption spectraspectra ofof blubluee sapphiressapphires spectrumspectrum typicaltypical ofof rubiesrubies fromfrom thethe fromfrom thethe 'metamorphic''metamorphic' suitessuites iinn WestWest PailinPailin Thai/CambodianThai/Cambodian borderborder regionregion (Figure 13b) andand BarringtonBarrington areare dominateddominated byby Fe3+ bandsbands withwith aann absorptionabsorption 'shoulder'shoulder'' aroundaround inin thethe ultravioleultraviolett (375,(375, 383877 nm)nm) andand visiblevisible 330330 nnmm thathatt reflectsreflects relativelrelativelyy highhigh FeFe- regionregion (450,(450, 460460,, 469469 nm),nm), anandd bbyy a broadbroad contents (mostly about 0.3-0.7% Fe2003; 22+ 4+ contents (mostly about 0.3-0.7% Fe2 3 Fe +--Ti Ti4+ charge-transfecharge-transferr betweebetweenn ca.ca. 550550 andand Schwarz, in prep.) and appears (Figure 13c) Schwarz, in prep.) and appears (Figure 13c) 750750 nmnm (Figure 15a). ThereThere isis nnoo significantsignificant equally among Barrington and Pailin 2+ 3+ equally among Barrington and Pailin Fe2+-Fe-Fe3+ charge-transfercharge-transfer absorptionabsorption towardtoward corundums. corundums. thethe near-infrared.near-infrared. IronIron anandd titaniumtitanium areare thethe dominantdominant PracticallyPractically allall absorptioabsorptionn spectraspectra colour-causingcolour-causing elementselements inin blueblue sapphires.sapphires. observedobserved inin ththee 'metamorphic''metamorphic' corundumscorundums TheThe absorptionabsorption bandsbands andand characteristicscharacteristics inin fromfrom BarringtonBarrington andand WestWest PailinPailin representrepresent a spectraspectra ooff blueblue sapphiressapphires areare relatedrelated ttoo thethe combinationcombination ofof FeFe,, TiTi anandd CrCr bandsbands withwith followingfollowing mechanisms:mechanisms: variationsvariations inin ththee relativerelative intensitiesintensities ofof thethe - sharpsharp bandsbands inin thethe ultravioletultraviolet atat 375375 andand absorptionabsorption bandbandss (Figures 15b and 15c). 387387 nmnm,, duedue toto disperseddispersed Fe33++;; Consequently,Consequently, somesome 'blue''blue' sapphiressapphires fromfrom - sharpsharp bandsbands inin thethe visiblevisible regionregion atat 450,450, thethe 'metamorphic''metamorphic' suitessuites showshow considerableconsiderable 460460 andand 469469 nm,nm, duduee ttoo disperseddispersed Fe3+3+;; CrCr componentscomponents inin theitheirr absorptionabsorption spectraspectra 79 whicwhichh cacann bebe seenseen inin a hand-heldhand-held 19 - broadbroad bandsbands withwith absorptionabsorption maximamaxima spectroscope. betweebetweenn 550550 andand 600600 nmnm (ordinary(ordinary rayray spectroscope. spectrumspectrum)) andand betweenbetween 680680 andand 750750 nmnm (extraordinary(extraordinary rayray spectrum),spectrum), relatedrelated toto DiscussioDiscussionn Fe22++--Ti Ti4+4+ intervalenceintervalence charge-transfercharge-transfer Clearly,Clearly, corundumscorundums frofromm twtwoo distinctdistinct processeprocessess (IVCT).(IVCT). Fe22++-Ti-Ti4+ dominateddominated suitessuites surfacedsurfaced witwithh basaltibasalticc eruptionseruptions atat spectrspectraa areare typicaltypical forfor blubluee sapphiressapphires bothboth BarringtoBarringtonn andand Pailin.Pailin. BotBothh exhibitexhibit originatinoriginatingg fromfrom KashmirKashmir,, MyanmarMyanmar andand surfacesurface featuresfeatures relatedrelated ttoo magmaticmagmatic SriSri LankaLanka (d.(cf. SchwarzSchwarz et al.,al, 1996);1996); corrosioncorrosion ofof formerformer embeddedembedded crystalcrystal sitessites - anan increasingincreasing absorptionabsorption towardstowards thethe nearnear andand thethe trigonatrigonall crystallographiccrystallographic structurestructure infrareinfraredd (800-900(800-900 nmnm;; Figure 14a), duduee toto (Coenraads,(Coenraads, 1992b,1992b, andand Figure 6 ofof thisthis 22+ 3+ Fe +-Fe-Fe + chargecharge transfetransferr processes.processes. study).study). AmonAmongg thesthesee araree 'needle-like''needle-like' AlthougAlthoughh thisthis hashas beebeenn consideredconsidered typicaltypical texturestextures recentlrecentlyy illustratedillustrated frofromm sapphiressapphires foforr sapphiressapphires fromfrom basaltibasalticc sources,sources, thethe atat Cyangugu,Cyangugu, RwandaRwanda,, AfricAfricaa (Krzemnicki(Krzemnicki et phenomenophenomenonn isis notnot entirelyentirely restrictedrestricted toto al.,al, 1996).1996). ThesThesee authorsauthors attributattributee thethe needlesneedles 'basaltic'basaltic'' sapphiressapphires aass itit alsoalso appearsappears inin ttoo protectioprotectionn ofof ththee corundumcorundum byby plagioclaseplagioclase sapphiresapphiress fromfrom AndranondambAndranondamboo inin crystalscrystals thathatt crystallizecrystallizedd frofromm ththee coarsecoarse MadagascaMadagascarr whichwhich originateoriginate fromfrom a basalbasaltt hosthost,, butbut havhavee sincesince weatheredweathered away.away. skarn-typskarn-typee geneticgenetic environmenenvironmentt (Schwarz(Schwarz SimilarSimilar needle-likneedle-likee texturetexturess havhavee beenbeen et al,al., 1996).1996). illustratedillustrated fromfrom corundumscorundums frofromm otherother areasareas AbsorptioAbsorptionn spectraspectra dominateddominated byby Fe-Fe-TTii (Coenraads,(Coenraads, 19921992 bb;; GuoGuo et al,al., 1996)1996) andand havehave andand Fe-FF~-Fee charge-transfercharge-transfer mechanismsmechanisms beebeenn interpretedinterpreted asas thethe resultresultss ooff differentialdifferential typifytypify blubluee sapphiressapphires fromfrom EastEast PailinPailin corrosioncorrosion ofof twinnintwinningg planesplanes.. Thus,Thus, whilewhile (Figure 14a). TheyThey alsoalso appearappear iinn thethe 'basaltic''basaltic' largelarge,, flatteflatterr andand squarer-endedsquarer-ended ridgeridgess inin (Figure 14b) suitessuites iinn WestWest PailinPailin andand CyanguguCyangugu sapphiresapphire maymay represenrepresentt formerformer Distinctive gem corundum suites fromfrom discrete basalt fieldsfields randomrandom sheathssheaths ofof plagioclaseplagioclase,, ththee ridge-likeridge-like mineralmineral analysesanalyses (Table lIlA,1IIA, B) werewere texturestextures ofof BarringtonBarrington anandd PallinPailin materiamateriall areare subjectesubjectedd ttoo thethe Mg-FMg-Fee exchangeexchange sapphirinesapphirine- consideredconsidered toto largelylargely stemstem fromfrom crystallocrystallo- spinelspinel thermometerthermometer calculationscalculations ofof OwenOwen graphicallygraphically controlledcontrolled corrosioncorrosion.. FusedFused crustscrusts andand Greenough,Greenough, 1991,1991, whicwhichh werweree useusedd inin onon somesome corundumscorundums andand compositescomposites suggestsuggest ththee BarringtonBarrington study.study. ThisThis thermometerthermometer usesuses littlelittle alluvialalluvial transporttransport fromfrom theirtheir sourcesource.. anan increaseincrease inin temperaturtemperaturee dependencedependence withwith MorMoree thanthan oneone generationgeneration ofof corundumcorundum iiss ththee partitioningpartitioning co-efficientco-efficient KdKd forfor MgMg andand seenseen withiwithinn ththee fancyfancy colourecolouredd suite.suite. SmallSmall FFee inin thethe sapphirinesapphirine (sa)/spinel(sa)/spinel (sp)(sp) pairpair.. TheThe hexagonalhexagonal crystalscrystals ooff whitewhite oror palepale yellowyellow formulationformulation isis T (0C)(°C) = [800[800 + (228(228 IInn corundumcorundum withoutwithout significantsignificant trace-elementtrace-element Kd)]-273Kd)]- 273,, wherwheree KdKd = (XSPF/XSPMg)/(XspFe/XspMg)/ contentscontents areare intergrownintergrown withwith oror includedincluded inin XsaF/XsaXsaFe/XsaM )),, witwithh X representingrepresenting thethe molarmolar largerlarger blubluee corundumscorundums containingcontaining FFee asas thethe fractionfractionss ofof FFee andand MgMg inin ththee minerals.minerals. mainmain tractracee element.element. SomSomee featuresfeatures typicaltypical ooff CalculationsCalculations basebasedd onon a sapphirine-spinelsapphirine-spinel 2+ ThaiThai rubyruby suitessuites suchsuch asas decrepitationdecrepitation haloeshaloes pairpair (Job(Job 4.3,4.3, Table IIIA) IIIA) gave gav e 772°C772°C (Fe(Fe2+ 2+ 3+ (Giibelin(Gübelin andand Koivula,Koivula, 1986)1986) appearappear inin bothboth calculation)calculation) andand 943°C943°C (Fe2+ andand Fe3+ BarringtoBarringtonn andand WesWestt PailinPailin rubies,rubies, recalculation).recalculation). ThiThiss suggestssuggests comparablecomparable illustratingillustrating thathatt suchsuch featuresfeatures areare notnot crystallisatiocrystallisationn temperaturetemperaturess forfor bothboth PailinPailin exclusiveexclusive toto ThaiThai rubiesrubies.. andand BarringtonBarrington suitessuites.. ThThee trace-elementrace-elementt andand absorptionabsorption characteristicscharacteristics ofof thethe fancyfancy colouredcoloured Origin of the metamorphic corundum suite corundumscorundums andand co-existingco-existing mineralsminerals PossiblePossible ongmsorigins forfor BarringtonBarrington (Figures 11, 11, 12, 12, 13 13 and and 15) 15) are ar econsidered considered to t o corundumscorundums thathatt favourfavour metamorphicmetamorphic oror characterisecharacterise corundumcorundum assemblagesassemblages metasomatimetasomaticc sourcessources havhavee beebeenn outlinedoutlined byby produceproducedd byby metamorphicmetamorphic recrystallizationrecrystallization SutherlandSutherland andand Coenraads,Coenraads, 19961996.. ofof aluminousaluminous materialmaterial.. WhetherWhether thisthis 80 80 CrystallisationCrystallisation temperaturestemperatures forfor BarringtonBarrington metamorphismetamorphismm originatedoriginated fromfrom contactcontact corundum-sapphirine-spinelcorundum-sapphirine-spinel assemblagesassemblages metamorphismetamorphismm relatedrelated ttoo ththee basalticbasaltic werewere estimatedestimated atat aroundaround 780-940°C,780-940°C, withwith magmasmagmas oror fromfrom anan earlierearlier unrelatedunrelated subsequentsubsequent reactioreactionn witwithh magmatimagmaticc hostshosts metamorphicmetamorphic eventevent isis nonott clearclear onon presentpresent takintakingg placeplace aroundaround 1000°C.1000°C. WesWestt PailinPailin data.data. Figure 14: Representative absorption spectra of blue-green-yellow 'basaltic'basaltic type sapphires fromfrom EastEast Pailin and East Australia.Australia. (a) Absorption spectrum of blue sapphire fromfrom EastEast PailinPailin miningmining region,region, withwith absorptionabsorption bandsbands duedue to FeFe2+-Ti4+2+-Ti4+ and Fe22++-Fe3+-Fe3+ charge transfer (0,(o, ordinary ray; e, extraordinary ray). (b) Typical absorptionabsorption spectrumspectrum of blueblue 'basaltic''basaltic' typetype sapphiresapphire fromfrom EastEast AustraliaAustralia (New(New SouthSouth WalesWales and Queensland mining areas). Blue absorption minimum (light transmission) only in the blue spectral region. a b c 0 .2 0...... 0 Vl .0 0 / '"bO ,/ .5 e Vl v e b'" .5 ---- / 400 600 800 nm 400 600 800 nm /J.. Gemm., 1998,26,2,65-85 1998,26, 2, 65-85 c s:: .9 e-o is '"gp 'iii ~u .5 d 81 e 1 IJ1 400 600 800 nm (c) Typical absorption spectrum ofgreen 'basaltic' typesapphire from East Australia (New South Wales andQueensland miningareas). Two absorption minima in violet-blue region andblue-green region, resulting in (blue-) green body colours. (d) Absorption spectrum ofyellow 'basaltic' typesapphire from East Australia (New South Wales and Queensland miningareas). Yellow broad transmission over thewhole green-yellow-orange spectral region. (e) Absorption spectrum of blue 'basaltic' typesapphires with high Fe and Ti contents. The relatively strong absorption band in the500to 600 nm region is caused by Fe2+-Ti4+ charge transfer. Distinctive gem corundum suites from discrete basalt fields a § '.C j co'" .~ ill b .S b \r~ 82 82 I I I I -----I I c 400 600 800 nm Figure 15: Absorption spectra of 'metamorphic' type fancy colour corundums from Barrington and West Pailin corundum suites.suites. (a) Blue sapphire, with dominating Fe3+Fe3+ bands in the UV and visible region accompanied by the broad absorption band about 550 to 600 nm due to F^-TiFe2+-Ti4+4* charge transfer.transfer. (b) Fancy colour corundumcorundum fromfrom 'metamorphic''metamorphic' type type Barrington Barrington and and West West Pailin Pailin suites: suites: typical typical spectrum spectrum showing strong FeFe3+3* andand Fe2+-Ti4+Fe2*-^4* chargecharge transfer transfer absorption absorption bands bands with with weak weak Cr'+ Cr bands.3* bands. (c) Fancy colour corundum with dominant cy3+Cr3* absorption spectrum combined with weak FeFe3+3* andand FeFe2+-Ti4+2*-^4* charge transfer bands. J. Gemm., 1998,1998,26,2, 26, 2, 65-8565-85 Origin of the 'basaltic''basaltic' corundumscorundums witwithh thosthosee fromfrom otherother EastEast AustraliaAustraliann andand AlthougAlthoughh subsidiarysubsidiary atat BarringtonBarrington andand EastEast PailinPailin gemfieldsgemfields (Tables II andand II).II). SimilarSimilar WestWest PailinPailin,, 'basaltic''basaltic' corundumscorundums dominatedominate bimodalbimodal suitessuites alsoalso existexist elsewhere,elsewhere, suitessuites elsewherelsewheree inin EastEast AustraliAustraliaa andand Pailin.Pailin. e.g.e.g. TumbarumbaTumbarumba inin thethe SnowySnowy RiveRiverr basaltbasalt TheThe corundumcorundumss rangerange intointo higherhigher GaGa field,field, EasEastt AustraliAustraliaa (MacNevin(MacNevin andand Holmes,Holmes, ) 1980),1980), betweenbetween ChanthaburiChanthaburi andand Trat,Trat, contentscontents (up(up toto 0.040.04 wwtt % GaZ20033) andand lowerlower ThailandThailand (Hughes,(Hughes, 1990)1990) anandd possiblypossibly inin Cr220033/GaZ20033 (always(always <1) Distinctive gem corundum suites fromfrom discrete basalt fieldsfields SutherlandSutherland et al.,al., 1998) 1998 )are are typically typically high high in in U U Coenraads,Coenraads, RR,R.R., 1992a.1992a. SapphiresSapphires andand rubiesrubies associatedassociated andand Th,Th, butbut somesome areare muchmuch lessless so.so. MoreMore withwith volcanicvolcanic provinces:provinces: InclusionsInclusions andand surfacesurface featuresfeatures shedshed lightlight onon theirtheir origin,origin, AustralianAustralian detaileddetailed workwork onon SouthSouth EastEast AsianAsian Gemmologist, 18(3), 18(3) 70-80, 70-8 0 corundumcorundum suitessuites willwill helphelp definedefine corundumcorundum Coenraads,Coenraads, RR,R.R., 1992b.1992b. SurfaceSurface featuresfeatures ofof naturalnatural rubiesrubies sourcessources belobeloww thesethese basaltibasalticc fields.fields. andand sapphiressapphires associatedassociated witwithh volcanicvolcanic provincesprovinces.. Journal of of Gemmology, Gemmology, 23(3), 23 (3)151-60, 151-6 0 Coenraads,Coenraads, RR,R.R., Sutherland,Sutherland, EL.,F.L. ,and and Kinny, Kinny ,P.D., P.D. ,1990. 1990 The. Th e AcknowledgementsAcknowledgements originorigin ofof sapphires:sapphires: U-PbU-Pb datingdating ofof zirconzircon inclusionsinclusions shedssheds newnew light.light. Mineralogical Magazine, Magazine, 54, 113-2254, 113-2 2 TheThe latelate A.W.A.W. ChubbChubb ofof Gloucester,Gloucester, Coldham,Coldham, T.,T., 1985.1985. SapphiresSapphires fromfrom Australia.Australia. Gems & NeNeww SouthSouth Wales,Wales, providedprovided materialmaterial fromfrom Gemology, 21(3), 21(3) 13-46, 13-4 6 thethe Barrington-GloucesterBarrington-Gloucester TopsTops area.area. Davis,Davis, D.W.,D.W., andand Barr,Barr, S.M.,S.M., 1995.1995. U-PbU-Pb datingdating ofof 1-101-10 MMaa RE.R.E. Pogson,Pogson, G.G. Avern,Avern, B.J.B.J. Barron,Barron, S.S. FolwellFolwell mantlemantle zirconzircon megacrystsmegacrysts fromfrom SouthSouth EastEast Asia.Asia. Geological Association of Canada/MineralogicalCanada/Mineralogical andand R. Springthorpe,Springthorpe, AustralianAustralian Museum,Museum, Association of of Canada Canada Annual Annual Meeting, Meeting, Victoria, Victoria, 20, A23 20 , A23 assistedassisted inin preparationpreparation ofof mineralmineral datadata andand Giibelin,Gübelin, E.J.,E.J., andand Koivula,Koivula, J.L,J.I., 1986.1986. PhotoatlasPhotoatlas of ofinclusions inclusions thethe script.script. TheThe AustralianAustralian MuseumMuseum TrustTrust in gemstones.gemstones. ABC AB CEdition, Edition Zurich, Zuric h suppliedsupplied fundsfunds throughthrough TheThe GeodiversityGeodiversity Guo,Guo, J.,J., Wang,Wang, F.,E, andand Yakoumelos,Yakoumelos, G.,G., 1992.1992. SapphiresSapphires Research Group. P. Kenne well, Cluff fromfrom Changle,Changle, inin ShandongShandong province,province, China.China. Gems & & Research Group. P. Kennewell, Cluff Gemology, 28(4), 28(4) 225-60, 225-6 0 ResourcesResources Pacific,Pacific, Sydney,Sydney, andand G.G. Oakes,Oakes, Guo,Guo, J.E,J.F., O'Reilly,O'Reilly, S.Y.,S.Y., andand Griffin,Griffin, W.L.,W.L. ,1996. 1996 .Corundum Corundum NeNeww SouthSouth WalesWales DepartmentDepartment ofof MineralMineral fromfrom basalticbasaltic terrains:terrains: anan inclusioninclusion approachapproach toto thethe Resources,Resources, lentlent materialmaterial forfor study.study. enigma.enigma. Contributions to toMineralogy Mineralogy and andPetrology, Petrology, 122, 122, R. Flossman,Flossman, UniversityUniversity ofof NewNew SouthSouth WalesWales,, 368-86368-86 prepared analytical mounts, and Hughes,Hughes, RW.,R.W., 1990.1990. Corundum. Butterworth-Heinemann, Butterworth-Heinemann , prepared analytical mounts, and LondonLondon C.C. NockoldsNockolds,, UniversityUniversity ofof Sydney,Sydney, arrangedarranged Hughes,Hughes, R.W.,R.W., 1997.1997. Ruby and and sapphire. sapphire. RW.H. R.W.H Publishing,. Publishing , analyticalanalytical support.support. T.T. ColdColdham ham,, SapphexSapphex Boulder,Boulder, Co.,Co., VSAUSA SydneySydney andand R. Maynard,Maynard, BeverleyBeverley HillsHills,, Irving,Irving, AI.,A.J., 1986.1986. PolybaricPolybaric magmamagma mixingmixing inin alkalialkali basaltsbasalts andand kimberlites:kimberlites: EvidenceEvidence fromfrom corundum,corundum, zirconzircon andand Sydney,Sydney, providedprovided lapidarylapidary assistance.assistance. 8484 ilmeniteilmenite megacrysts.megacrysts. In:In: Smith,Smith, C.B.C.B. (compl.)(compl.) FourthFourth K.K. Williams,Williams, RenishawRenishaw TransducersTransducers Div.,Div, InternationalInternational KimberliteKimberlite ConferenceConference ExtendedExtended U.K.,U.K., helpedhelped withwith RamanRaman laserlaser probeprobe Abstracts,Abstracts, Perth,Perth, WesternWestern Australia,Australia, AugustAugust 11-15,11-15, 1986.1986 . facilities.facilities. Prof.Prof. W.B.W.B. Stern,Stern, UniversityUniversity ooff Geological Society Society of Australia of Australia Abstracts Abstracts Series, 16,Series, 262-64 16 , 262-64 Basel,Basel, Switzerland,Switzerland, programmeprogrammedd andand Jobbins,Jobbins, E.A,E.A., andand Berrange,Berrangé, J.P.,J.P., 1981.1981. TheThe PailinPailin rubyruby andand assisted with the trace-element analyses. sapphiresapphire gemfield,gemfield, Cambodia.Cambodia. Journal of of Gemmology, Gemmology, assisted with the trace-element analyses. 17(8),555-6717(8), 555-67 G.G. Bosshart,Bosshart, GiibelinGübelin Laboratories,Laboratories, Lucerne,Lucerne, JohnsonJohnson,, RW.,R.W., (comp.(comp. andand ed.),ed.), 1989.1989. Intraplate volcanism volcanism Switzerland,Switzerland, suppliedsupplied informationinformation onon LaosLaos in Eastern Australia and New Zealand. CambridgeCambridg e corundums.corundums. DrDr E.E. Giibelin,Gübelin, Lucerne,Lucerne, UniversityUniversity Press,Press, CambridgeCambridge provided numerous samples from his private Keller,Keller, P.C.P.c.,, 1990.1990. GemstonesGemstones and and their their origins. origins. Van VaNostrandn Nostran d provided numerous samples from his private Reinhold,Reinhold, NeNeww YorYorkk collection,collection, whilewhile GebriiderGebrüder BankBank Company,Company, Kiefert,Kiefert, L.,L., Schmetzer,Schmetzer, K.,K., Krzemnicki,Krzemnicki, M.s.,M.S., Bernhardt,Bernhardt, Idar-Oberstein,Idar-Oberstein, suppliedsupplied PailinPailin sapphires.sapphires. H.-J.,H.-J., andand Hiinni,Hänni, H.A.,H.A., 1996.1996. SapphiresSapphires fromfrom thethe AAA.A. Levinson,Levinson, UniversityUniversity ofof Calgary,Calgary, AndranondamboAndranondambo area,area, Madagascar.Madagascar. Journal ofof Canada,Canada, andand othersothers reviewedreviewed thethe script.script. Gemmology, 25(3), 25(3) 185-209, 185-20 9 Koivula,Koivula, J.L,J.I., andand Fryer,Fryer, C.W.,C.W., 1987.1987. SapphirineSapphirine (not(not sapphire)sapphire) inin a rubyruby fromfrom BoBo RaiRai,, Thailand.Thailand. Journal of of ReferencesReferences Gemmology, 20(6), 20(6) 369-70, 369-7 0 Krzemnicki,Krzemnicki, M.S.,M.S., Hiinni,Hänni, H.A,H.A., Guggenheim,Guggenheim, R.,R., andand Berrange,Berrangé, J.P.,J.P., andand Jobbins,Jobbins, E.A.,E.A., 1976.1976. TheThe geology,geology, Mathys,Mathys, D.,D., 1996.1996. InvestigationsInvestigations onon sapphiressapphires fromfrom anan gemmology,gemmology, miningmining methodsmethods andand economiceconomic potentialpotential ofof alkalialkali basalt,basalt, SouthSouth WestWest Rwanda.Rwanda. Journal ofof thethe PallinPailin rubyruby andand sapphiresapphire gem-field,gem-field, KlunerKhmer Republic.Republic. Gemmology, 25(2), 25(2) 90-106, 90-10 6 Institute of of Geological Geological Sciences Sciences Report, Report, 35, 1-32, 35 3, 1-32maps, 3 maps Levinson,Levinson, AA,A.A., andand Cook,Cook, F.A.EA.,, 1994.1994. GemGem corundumcorundum inin Bosshart,Bosshart, G.,G., 1995.1995. SapphiresSapphires andand rubiesrubies fromfrom LaosLaos.. alkalialkali basalt:basalt: OriginOrigin andand occurrence.occurrence. Gems & & Gemology, Gemology, Proceeding'Proceedings of the 25th International Gemmological 30(4),30(4), 253--62253-62 Conference, Rayong, Rayong, Thailand, Thailand, 23-27 23-27 October, October, 1995 1995 MacNevinMacNevin,, AA,A.A., anandd HolmesHolmes,, G.G.,G.G., 1980.1980. Gemstones.Gemstones. TheThe Bunopas,Bunopas, 5.,S., andand Vella,Vella, P.,P., 19~2.1992. GeotectonicsGeotectonics andand geologicalgeological MineralMineral IndustryIndustry ofof NewNew SouthSouth Wales,Wales, GeologicalGeological evolutionevolution ofof Thailand.Thailand. In:In: Piancharoen,Piancharoen, C.C. (ed.)(ed.).. Survey ofof New New South South Wales, Wales, 18, 18 2nd, 2n Edition,d Edition 119, 11 pp9 p p Supplementary volumevolume of of proceedings proceedings of aof Nationala National Milisenda,Milisenda, c.c.,C.C., anandd Henn,Henn, V.,U., 1996.1996. CompositionalCompositional Conference on onGeological Geological Resources Resources of Thailand. of Thailand. Department Departmen characteristicscharacteristict s ofof sapphiressapphires fromfrom a newnew findfind inin ofof MineralMineral Resources,Resources, Bangkok,Bangkok, Thailand,Thailand, 209-28209-28 MadagascarMadagascar.. Journal of of Gemmology, Gemmology, 25(3), 25 (3)177-84, 177-8 4 J.J . Gemm., 1998, 1998, 26, 26, 2, 2,65-85 65-85 MummeMumme,, LA,I.A., 1988.1988. The world of sapphires. MummeMumme (ed.)(ed.) TheThe NicholasNicholas RocRockk Symposium:Symposium: AlkalinAlkalinee rockrockss Publications,Publications, PortPort Hacking,Hacking, AustraliaAustralia andand theirtheir associatedassociated mineralisationmineralisation.. Australian Journal Journal Olliver,Olliver, I.G.,J.G., and and Townsend, Townsend, I.I., I.J. ,1990. 1990 .Gemstones Gemstones in Australia. in Australia. of Earth Sciences, Sciences, 43, 43 323-43, 323-4 3 AustralianAustralian GovernmentGovernment PublishingPublishing Service,Service, CanberraCanberra Sutherland,Sutherland, EL.,F.L., andand Coenraads,Coenraads, RR,R.R., 1996.1996. AAnn unusualunusual O'Reilly,O'Reilly, S.Y.,S.Y., andand Zhang,Zhang, M.M.,, 1995.1995. GeochemicalGeochemical ruby-sapphire-sapphirine-spinelruby-sapphire-sapphirine-spinel assemblageassemblage fromfrom thethe characteristicscharacteristics ofof lava-fieldlava-field basaltsbasalts fromfrom easterneastern TertiaryTertiary BarringtonBarrington volcanicvolcanic provinceprovince,, NeNeww SouthSouth AustraliaAustralia andand inferredinferred sources:sources: connectionsconnections witwithh thethe WalesWales,, Australia.Australia. Mineralogical Magazine, Magazine, 60, 60623-38, 623-3 8 sub-continentalsub-continental lithosphericlithospheric mantlemantle.. Contributions to to Sutherland,Sutherland, EL.,F.L., andand Fanning,Fanning, CM.,C.M., 1996.1996. MagmatismMagmatism Mineralogy and and Petrology, Petrology, 121, 121 148-70, 148-7 0 belobeloww BarringtonBarrington volcanovolcano,, NSWNSW:: BaseBasedd oonn basalbasaltt andand Owen,Owen, J.Y.,J.V., andand Greenough,Greenough, J.D.,J.D., 1991.1991. AnAn empircalempircal zirconzircon megacrystmegacryst dating.dating. Geological Society Society of Australia of Australia sapphirine-spinelsapphirine-spinel Mg-FMg-Fee exchangexchangee thermometethermometerr andand Abstract Series, Series, 41, 41 426, 42 6 itsits applicationapplication ttoo high-gradhigh-gradee xenolithsxenoliths inin ththee PopePope Sutherland,Sutherland, EL.,F.L., Barron,Barron, B.J.,B.J., andand WebbWebb,, G.,G., 19931993.. HarbourHarbour dyke,dyke, NovaNova Scotia,Scotia, Canada.Canada. Lithos, 26, 26 317-32, 317-3 2 BarringtonBarrington volcanvolcanoo - repeaterepeatedd gemstonegemstone eruptionseruptions Pain,Pain, CE,C.F., 1983.1983. GeomorphologyGeomorphology ofof ththee BarringtoBarringtonn TopTopss (zircon,(zircon, sapphiresapphire andand ruby)ruby) atat thethe edgeedge ofof thethe SydneySydney area,area, NeNeww SouthSouth WalesWales.. JournalJournal of of the the Geological Geological Society Society BasinBasin.. In:In: DieselDiesel,, C.F.KCEK.. (conven.(conven.)) Twenty-SeventhTwenty-Seventh of Australia, 30,187-94 30, 187-94 Newcastle Symposium Symposium on onAdvances Advances in thein theStudy Study of the of the Schwarz,Schwarz, D.D.,, inin prep.prep. TheThe chemicalchemical propertiesproperties ooff Sydney Basin.Basin. University Universit yof o Newcastle,f Newcastle Department, Departmen oft o f corundumscorundums (rubies(rubies andand sapphires)sapphires) fromfrom EasternEastern AsiAsiaa GeologyGeology,, PublicationPublication 545,545, 137-44137-44 (Thailand,(Thailand, Cambodia,Cambodia, LaosLaos,, Vietnam,Vietnam, Burma,Burma, etc.etc.)) Sutherland,Sutherland, EL.,F.L., Hoskin,Hoskin, P.W.O.,P.W.O., Fanning,Fanning, CM.,C.M., andand Schwarz,Schwarz, D.,D., Petsch,Petsch, E.J.E.J.,, andand Kanis,Kanis, J.,J., 1996.1996. SapphiresSapphires CoenraadsCoenraads,, RR,R.R., 1998.1998. ModelsModels ofof corundumcorundum originorigin fromfrom thethe AndranondamboAndranondambo regionregion,, MadagascarMadagascar.. Gems frofromm alkalialkali basaltbasalt terrainsterrains:: a re-appraisalre-appraisal.. IInn prep.prep. & Gemology, 32(2), 32(2) 80-99, 80-9 9 Suttirat,Suttirat, C,C., Charusiri,Charusiri, P.P.,, FarrarFarrar,, E.E.,, andand Clark,Clark, A.H.AH.,, 1994.1994. 40 39 Smith,Smith, C.P.CP.,, Kammerling,Kammerling, R.C.R.C,, Keller,Keller, AS.,A.S., PerettiPeretti,, A.A.,, NeNeww -VJ Ar/Ar 1'9A Arr geochronologgeochronologyy anandd characteristiccharacteristicss ooff Scarratt,Scarratt, K.V.,K.V., Khoa,Khoa, N.D.N.D.,, andand Repetto,Repetto, S.,S., 19951995.. somesome CenozoicCenozoic basaltbasaltss inin Thailand.Thailand. Proceedings of ofthe the SapphiresSapphires fromfrom SouthernSouthern VietnamVietnam,, Gems && Gemology, Gemology, International Symposium Symposium on: on:Stratigraphic Stratigraphi Correlationc Correlation of of 31(3),31(3), 168-86168-86 Southeast Asia, 15-2015-20 NovemberNovember 1994,1994, Bangkok,Bangkok, Stern,Stern, B.W.,B.W., 1984.1984. ZurZur SimultananalyseSimultananalyse vovonn SilicatenSilicaten Thailand,306-21Thailand, 306-21 (Hauptkomponenenten,(Hauptkomponenenten, Spuren)Spuren) mittelmittelss energieenergie- VichitVichit,, P.,P., 1992.1992. GemstonesGemstones inin Thailand.Thailand. In:In: PiancharoenPiancharoen,, C.C dispersiverdispersiver R6ntgenfluoreszenz-SpektrometrieRöntgenfluoreszenz-Spektrometrie (EDS(EDS- (ed.(ed.)) Supplementary Volume Volume of Proceedingsof Proceedings of a National of a National XFA)XFA).. FreseniusFresenius Z. Z. Analaytical Analaytical Chemistry, Chemistry, 2560, 2560 1-9, 1-9 Conference on onGeological Geological Resources Resources of Thailand. of Thailand. Department Departmen t Sutherland,Sutherland, L.,L., 1991.1991. Gemstones of of the the southern southern continents. continents. ooff MineralMineral Resources,Resources, Bangkok,Bangkok, Thailand,Thailand, 124-50124-50 ReedReed BooksBooks,, SydneySydney WebbWebb,, G.G.,, 1997.1997. GemmologicalGemmological featuresfeatures ooff rubierubiess andand 85 85 Sutherland,Sutherland, EL.,F.L., 1996.1996. AlkalineAlkaline rocksrocks andand gemstonesgemstones,, sapphiressapphires fromfrom thethe BarringtoBarringtonn volcanovolcano,, easterneastern Australia:Australia: a revierevieww andand synthesis.synthesis. In:In: Sutherland,Sutherland, F.L.EL.,, Australia.Australia. The AustralianAustralian Gemmologist, Gemmologist, 19(11), 19(11) 471-75, 471-7 5 Princely Treasures by Geza von Habsburg f41.00 Traditional Jewellery of India by Oppi Untracht fSS.OO Prices quoted exclude postage and packing Gemmological Instruments Limited, 27 Greville Street, london ECl N 8SU. Tel: 0171 -404 3334 Fax: 0171 -404 8843 Distinctive gem gem corundum corundum suites suites from from discrete discrete basalt basaltfields fields Peridot from the Black Rock Summit lava flow, Nye County, Nevada, USA John R. Führbach, B.Sc., FGA, GG Amarillo, Texas, USA ABSTRACT: An extinct volcano's alkaline basalt lava flow has fissures and tumuli filled with large phenocrysts of peridot and occurs near Black Rock Summit in east central Nevada, USA. The peridot was studied to determine chemical, optical and physical properties and the variations in these properties from peridot from other world occurrences. This little-known source provides peridot in varying shades of green to brown, similar to material found in a caldera known as Kilbourne Hole (Volcano), Dona Ana County, New Mexico, USA - some 1126 km distant. Several identified 'new' inclusions, not previously cited in the literature, are described. Though not mined commercially, the peridot is of interest due to its variation in colour from peridots of other world sources. 86 Introduction pproximately 277 km north-north-east of Las Vegas, Nevada, lies a desert Aarea of flatlands (Figure 1) sparsely dotted with playa lakes and mountain ranges and known as a 'pancake' desert. The northerly highway from Las Vegas passes by top-security military bases and desolate areas which historically represent the underground test area of over 800 nuclear weapons. Still farther north in a remote area will be found an extinct volcano, Lunar Crater, and black Figure 1: View of the cinder cone and very dark lava field looking easterly with the cinder cone volcanic lava flows of Cenozoic age listed on rising approximately 300 m from the desert floor. US Geological Survey maps as the Black Rock The lava field consists of jagged protrusions Summit lava flow. rising between 0.5 m and 10 m above the sandy In the Black Rock Summit lava flow can desert. be found one of the most diverse examples of peridot found in the world. The colour going back to 1500 BC, the study of peridot ranges from yellowish-brown through associated with volcanoes of high-alkali greenish-yellow into very dark 'muddy' olivine basalt will continue to be a 'new shades of brown. With a history of peridot discovery' event inasmuch as North America © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355-4565 q Balcer ..a Ol.doer Peak RaJnlcr SL ''(]~GOII Rocka H~~~A '" lone (SulTaIo Valley Honcycomll . . • D_ HWa<> ol'UmatOic BUlle ' ~E~rtRDck ="'1- MInerai ML t)Loa d ~~~'Kolob Kilbourne Hole 100, 200, 300, 400 KUometer, III ...... '" ... Figure 2: The western portion of the United States of America showing volcanic areas in the continental USA younger than five million years old (modified fromfrom SmithSmith andand Leudke, 1984).1984). providesprovides unlimiteunlimitedd numbernumberss ofof recordedrecorded attemptedattempted toto collectcollect specimensspecimens ooff peridotperidot volcanoesvolcanoes fromfrom thethe AleutiaAleutiann IslandsIslands intointo fromfrom 'little-known''little-known' sourcessources.. NumerouNumerouss tripstrips Alaska,Alaska, Canada,Canada, andand thethe continentalcontinental UnitedUnited werewere madmadee overover a five-yearfive-year perioperiodd toto States.States. TheThe WesternWestern UniteUnitedd StatesStates (Figure 2) 2) BlackBlack RocRockk SummitSummit lavalava flowflow ttoo collectcollect providesprovides a lifetimelifetime ofof studystudy foforr thethe specimens.specimens. AsAs eaceachh newnew sourcesource isis gemmologistgerhmologist withwith ititss readilreadilyy accessibleaccessible areasareas investigatedinvestigated a 'new''new' inclusioinclusionn hahass beenbeen forfor prospectinprospectingg forfor thithiss 'old''old' butbut currentlycurrently reportedreported thatthat isis characteristiccharacteristic ofof ththee peridotperidot little-respectedlittle-respected gem.gem. ofof ththee area.area. IInn anan efforteffort toto comparecompare peridotperidot fromfrom A basalbasaltt flowflow (Figure 1) 1) on on the the west wes tslope slope differentdifferent areasareas ofof ththee worldworld withwith regarregardd toto ofof thethe PancakPancakee RangeRange,, nearnear BlackBlack RocRockk opticaloptical andand physicalphysical data,data, asas welwelll asas Summit,Summit, NyNyee County,County, NevadaNevada,, iiss thethe characteristiccharacteristic inclusions,inclusions, thethe authorauthor hashas youngestyoungest uniunitt inin anan uppeupperr CenozoicCenozoic volcanicvolcanic Peridot fromfrom the Black Rock Summit lava flow, Nye County, Nevada, USAUSA 120 118' 116j 114j ------I-- -- L _ ----r - 42j I I I I ~~------+------~------~I~~j I Reno o o Austin I o Carson City o Ely I , LOCATIO OF I , , • LAVA FLOW I Black Rock I " o Tonopah Summit 38 ri------~--4---~~~~~------~1, j , o Goldfield ~, , 88 88 , , , , 25 0 0 100 Miles Figure 3: Index map of the State of Nevada, showing the location of Black Rock Summit lava flow (after Vitaliano and Harvey, 1965). fieldfield composedcomposed mainlymainly ofof cindercinder conescones andand longitudelongitude andand 38°29'38°29' northnorth latitude,latitude, andand isis ashash deposits.deposits. TheThe flowflow isis blackblack andand vesicularvesicular accessibleaccessible bbyy NevadNevadaa StateState HighwayHighway toto scoriaceousscoriaceous withwith thethe texturetexture ofof thethe NumbeNumberr 6 north-eastnorth-east fromfrom thethe citycity ofof non-scoriaceousnon-scoriaceous phasephase beingbeing porphyritic.porphyritic. TonopahTonopah (Figure 3). USUS GeologicalGeological SurveySurvey PhenocrystsPhenocrysts ofof olivine,olivine, pyroxenepyroxene,, andand topographictopographic mapsmaps whichwhich covercover thethe areaarea areare plagioclaseplagioclase areare fromfrom 1 emcm toto 2222 cemm long.long. BlackBlack RockRock SummitSummit (number(number 38115-E8),38115-E8), thethe WallWall (number(number 38115-D8),38115-D8), LunarLunar CraterCrater LocationLocation andand AccessAccess (number(number 38116-D1),38116-D1), andand MooresMoores StationStation SESE TheThe basaltbasalt flowflow isis smallsmall coveringcovering anan areaarea (number(number 38116-El)38116-E1) whichwhich areare 7.5 minuteminute approximatelyapproximately 8.0x4.88.0x4.8 kkmm atat 116°00'116°00' westwest quadranglesquadrangles (Map(Map scale:scale: 1:25000;1:25000; J./. Gemm., 1998,26,2,86-1021998,26,2, 86-102 ( ( I \~ CONTOUR INTERVAL 20 fEET oon(o LIHES 1l[I'R($[Hf 10.'00' CONTOURS CATUN IS MEAH SEA LEVEL Figure 4: Outline showing access to the Black Rock Summit lava flowflow from Nevada State HighwayHighway Number 6 and the offroad toto thethe encampment; encampment; basedbased on on US US Geological Geological Survey Survey topographic topographic maps. maps. Due Due to the nature of the scattered lava pieces andand thethe desertdesert sand,sand, it it isis highly highly recommendedrecommended that that onlyonly aa four four- wheel drive vehicle be used.used. 1"=20831"=2083 feet).feet). AA compositecomposite ofof thesethese fourfour mainmain highway;highway; however,however, adequateadequate suppliessupplies mapsmaps isis shownshown inin Figure 4. 4 . ofof foodfood andand especiallyespecially waterwater areare mandatorymandatory TheThe altitudealtitude variesvaries fromfrom 17611761 mm onon thethe asas thethe temperaturetemperature onon thethe lavalava flowflow inin JulyJuly desertdesert floorfloor toto 20622062 m atat thethe summit.summit. TheThe waswas measuredmeasured atat middaymidday inin excessexcess ofof 63°C!63°C! areaarea surroundingsurrounding thethe flowflow isis sandysandy desertdesert withwith shortshort drieddried grassgrass andand nono brush.brush. TypicalTypical GeologyGeology andand occurrenceoccurrence daytimedaytime temperaturestemperatures inin thethe summersummer areare inin A studystudy ofof thethe petrologypetrology andand mineralogymineralogy thethe rangerange ofof 35°C35°C toto 46°C46°C withwith slightslight coolingcooling ofof thethe lavalava flowflow waswas mademade byby VitalianoVitaliano andand desertdesert windswinds inin thethe latelate evenings;evenings; humidityhumidity HarveyHarvey (1965).(1965). TheThe followingfollowing isis takentaken fromfrom isis lessless thanthan 5 perper cent.cent. AccessAccess isis fromfrom thethe thethe introductionintroduction toto theirtheir paper:paper: Peridot fromfrom thethe BlackBlack RockRock SummitSummit lavalava flowflow,, NyNyee CountyCounty,, Nroada,Nevada, USAUSA issueissuedd frofromm thithiss crater;; ththee remainderemainderr floweflowedd frofromm aann orificorificee locatelocatedd neanearr ththee northeasternortheasternn extremitextremityy ooff ththee fissurefissure.. ThThee venventt ooff ththee cratecraterr iiss abouaboutt 9911 m iinn diametediameterr anandd iiss nonoww fillefilledd witwithh solidifiesolidifiedd lavlavaa uupp ttoo ththee levelevell ooff ththee breacbreachh iinn ththee wallwall:/ WithiWithinn ththee cratecraterr ththee surfacsurfacee ooff ththee lavlavaa (Figure 5) 5) is i sinfrequently infrequently dotteddotted withwith jagged jagged protuberanceprotuberancess callecalledd 'tumuli'tumuli'' (Figure 6) 6).. The The namnamee 'tumulus'tumulus'' wawass proposeproposedd bbyy DalDalyy (1914(1914)) (fro(fromm ththee LatiLatinn ''aa swelling-up')swelling-up'),, followinfollowingg ititss applicatioapplicationn ttoo certaicertainn prehistoriprehistoricc buriaburiall mounds)mounds).. DalDalyy recognizerecognizedd thathatt tumultumulii araree commocommonn iinn HawaiHawaiii anandd explaineexplainedd thethemm aass havinhavingg beebeenn raiseraisedd bbyy 'th'thee localocall hydrostatichydrostatic pressurpressuree ooff still-fluidstill-fluid lavlavaa beneatbeneathh ththee alreadalreadyy chilledchilled crust'crust',, a vievieww witwithh whicwhichh ththee authoauthorr concursconcurs.. TheThe followinfollowingg descriptiodescriptionn ooff ththee lavlavaa iiss quotequotedd fromfrom ththee papepaperr bbyy VitalianVitalianoo anandd HarveHarveyy (1965)(1965):: 'Outsid'Outsidee ththee cratecraterr iitt isis dominantlydominantly a pahoehoepahoehoe typtypee ofof lavalava.. ResidualResidual 90 90 monolithicmonolithic blockblockss ofof pyroclasticpyroclastic Figure 5: Centre of thethe lava field showing the material,material, nonoww scatteredscattered throughouthroughoutt ththee infrequently found tumuli which contain the flow,flow, maymay representrepresent fragmentsfragments fromfrom larger crystalscrystals ofof peridot. ThisThis particular tumulustumulus the breachbreach inin thethe cratercrater wallwall.. IInn ththee yielded a single peridot specimenspecimen which weighedweighed steepsteep north-westernnorth-western walwalll ooff 614.60 ctfctl longitudinallongitudinal depressiondepression iinn ththee lavalava threethree layerslayers areare exposed,exposed, eacheach 'The'The lavalava issuedissued fromfrom a breacbreachh inin thethe separatedseparated fromfrom thethe otherother bbyy thinthin southwestsouthwest wallwall ofof a smallsmall cindercinder cone,cone, scoriaceousscoriaceous horizons.horizons. TheThe thicknessthickness ooff oneone ofof severalseveral locatedlocated onon a N.20°EN.20°E.. thisthis locationlocation exceedsexceeds 1515 mm butbut thethe basebase trendingtrending fissure.. AboutAbout 90% ofof thethe lavalava ofof thethe lavalava waswas notnot observedobserved anywhereanywhere Figure 6: Tumili'Tumilï,', ''lavalava rises' or 'lava'lava pits' as defindefineded by Hawaii's Institute of Geophysics araree more prolific near the edgedgeses of the lava flowflow than in the centrcentre,e, rising from about 1.5 m to about 10 m and may be the result of pressure ridges. J.J. Gemm.Gemm.,, 19981998,26,2,86-102, 26, 2, 86-102 Figure 8: Typical specimen of the lava flow exhibiting single crystals of black augite,augite, colourless (appears white)white) oligoclaseoligoclase feldspar feldspar and and Figure 7: Variation in colour of the fragmentsfragments green peridot. Each crystal is approximatelyapproximately collected from the tumuli debris; all pieces 5 x 2.5 x 2.5 cm.cm. appear to be 'splintered' and 'spear-point'spear-point- shaped' and these represent typical sizes ofof facetablefacetable quality: 7.03 ct (18.3 x 7.9 x 5.7 mm); tumulitumuli andand coverscovers thethe floorsfloors isis siftedsifted toto 12.72 ct (26.7(26.7x11.1x10.1 x 11.1 x 10.1 mm); and 4.65 ct recoverrecover thethe gemgem materialmaterial.. TypicalTypical 'floor''floor' lavalava (19.6 x 6.7 x 6.9 mm). Photo by Maja DeMaggio. flowflow materialmaterial containscontains largelarge individualindividual crystalscrystals (Figure 8) ofof diopsidicdiopsidic augite,augite, 91 91 withiwithinn thethe confinesconfines ofof ththee perimeterperimeter andesineandesine andand peridotperidot (with(with 87%87% ofof thethe andand consequentlconsequentlyy ththee thicknessthickness couldcould forsteriteforsterite molecule)molecule) inin proximityproximity.. EuhedralEuhedral notnot bbee determined.determined. crystalscrystals ofof peridotperidot areare rarerare andand theitheirr facesfaces areare highlyhighly etchedetched oror resorberesorbedd (Figure 9). 9). 'TheThe rockrock isis blackblack,, vesicularvesicular andand porphyritiporphyriticc exceptexcept wherewhere markedmarked oxidaoxida tiontion attendingattending vesiculationvesiculation hahass coloredcolored Figure 9: A single crystal ofof peridot peridot in in lava. lava. Single Single itit redred.. ItsIts mostmost strikingstriking characteristiccharacteristic isis crystals are rare and this one has been partiallypartially thethe largelarge crystalscrystals ofof olivineolivine (peridot)(peridot),, rounded by chemical resorption. This faceting-faceting pyroxenpyroxenee andand plagioclase.'plagioclase/ quality peridot measuresmeasures 22 22x11 x 11 xx 9 9 mm. mm. VesiculaVesicularr walls ofof lavlavaa areare occasionallyoccasionally linedlined witwithh hydroushydrous ironiron oxideoxide oror withwith a buffbuff- colouredcoloured material.material. SpecimensSpecimens ofof peridotperidot largerlarger thanthan 2 x 2 cmcm areare generallygenerally fracturedfractured intointo elongatedelongated 'spear-point-shaped''spear-point-shaped' piecespieces (Figure 7); 7); those those in in the the central centra lportion portion of o fthe the lavalava flofloww areare darkerdarker iinn colourcolour andand ththee lighterlighter moremore 'yellowish''yellowish' andand moremore transparenttransparent materialmaterial isis foundfound withiwithinn thethe tumultumulii atat thethe peripherperipheryy ofof thethe lavalava flow.flow. TheThe interiorsinteriors ooff thethe tumulitumuli areare linedlined withwith lavalava whichwhich weathereweatheredd toto releasreleasee ththee peridotperidot andand colourlesscolourless plagioclasplagioclasee feldsparfeldspar andand augiteaugite crystals;crystals; thethe finefine powderpowderyy greygrey ashash whichwhich hashas decomposeddecomposed fromfrom ththee innerinner walls ofof thethe Peridot from thethe Black Rock Summit lavalava flow,flow, Nye County, Nevada, USAUSA Figure 11: This single crystal of peridot measuredmeasured approximately 77x5x2cm x 5 x 2 em and the surface hadhad been oxidized to iridescent colours resemblingresembling peacock feathers. feathers. Analogous Analogous coloration coloration was was experi experi enced in the laboratory when heating unalteredunaltered material toto 750°C750°Cfor for 1010 hours.hours. 92 92 Figure 10: The largest fissurefissure observed in the lava flow measured 22.23 x 7.91 cm and was Figure 12: Several hours of back-breaking workwork completely filled with peridot; the diameter of the resulted in the removal of the largest peridot coin is 17.9 mm.mm. crystal found.found. Unfortunately it cleaved into three pieces but when reassembled it measured TheThe largestlargest cavitycavity observedobserved inin thethe lavalava 70.070.0x43.0x26.0 x 43.0 x 26.0 mm and weighed 614.60 ctci flowflow (Figure 10) containedcontained nothingnothing butbut comprising three pieces weighing 140.00,140.00,156.20 156.20 peridotperidot andand removalremoval wawass onlyonly effectedeffected byby and 318.40 ct. ususee ofof a one-inchone-inch diamonddiamond corecore drill.drill. MosMostt ooff thethe peridotperidot waswas highlhighlyy fracturefracturedd wherewhere thethe outerouter areasareas ofof thethe peridoperidott metmet thethe lava.lava. TwoTwo ofof thethe largerlarger tumultumulii containedcontained largelarge erodederoded andand oxidizedoxidized crystalscrystals ofof peridotperidot (Figures 11 and 12) whichwhich exhibitedexhibited iridescenceiridescence onon thethe weathereweatheredd surface.surface. TheseThese largerlarger specimensspecimens couldcould onlyonly bebe removedremoved afterafter manymany hourshours ofof pickpick andand chiselchisel drillingdrilling aroundaround eacheach specimen.specimen. MaterialsMaterials andand methodsmethods OverOver 52005200 ctct ofof roughrough samplessamples werewere removedremoved andand segregatedsegregated byby colourcolour andand clarity,clarity, andand representativerepresentative facetedfaceted gemsgems werewere cut (Figure 13) 13) which whic hranged range din i nweight weigh tfrom from 0.550.55 ctct toto 15.9015.90 ct.ct. ColoursColours rangedranged fromfrom a J. Gemm., 1998,1998,26,2,86-102 26, 2, 86-102 Figure 13: This group of cut stones (0.55 to 6.47 ct) is representative of the colour variation of peridot from the Black Rock Summit lava flow.flow. NoteNote thethe predominance ofof brown.brown. Photo byby MajaMaja DiMaggio.DiMaggio. lightlight greenish-yellowgreenish-yellow throughthrough olive-greenolive-green intointo non-destructivenon-destructive methomethodd whichwhich isis similarsimilar inin brownish-greebrownish-greenn andand finallyfinally a darkdark brown.brown. principleprinciple ttoo energy-dispersiveenergy-dispersive X-rayX-ray GemmologicalGemmological propertiesproperties werewere obtainedobtained fromfrom fluorescencefluorescence (EDXRF).(EDXRF). ItIt employsemploys anan 3030 samplessamples representativerepresentative ofof thethe colourcolour rangerange.. acceleratoraccelerator toto drivedrive a high-speedhigh-speed streamstream ooff RefractiveRefractive indicesindices werweree determineddetermined witwithh a protonprotonss towardtoward thethe targetargett sample,sample, anandd eacheach RaynerRayner DialdexDialdex refractometerefractometerr andand GIAGIA highhigh- elementelement inin thethe samplesample respondsresponds byby intensityintensity sodium-vapoursodium-vapour lamp.lamp. RefractiveRefractive producinproducingg characteristiccharacteristic X-rays,X-rays, whichwhich areare indicesindices ofof grainsgrains takentaken atat smalsmalll intervalsintervals detectedetectedd andand countedcounted;; withinwithin minutesminutes ooff fromfrom edgeedge toto centrecentre ofof larglargee peridotperidot crystalscrystals exposure,exposure, a computercomputer produceproducess bothboth werewere determineddetermined byby ththee immersionimmersion method.method. quantitativequantitative andand qualitativequalitative data.data. 93 93 PleochroismPleochroism waswas determineddetermined witwithh a GIAGIA- GEMGEM polariscope,polariscope, RayneRaynerr andand GIAGIA calcitecalcite DescriptionDescription ofof thethe materialmaterial dichroscopes,dichroscopes, andand a modifiemodifiedd BauscBauschh & PeridotPeridot,, a magnesium-ironmagnesium-iron silicate,silicate, isis a LombLomb GIAGIA GemoliteGemolite microscopemicroscope.. SpecificSpecific membememberr ofof thethe olivineolivine groupgroup,, anan gravitiesgravities werewere measuremeasuredd hydrostaticallyhydrostatically isomorphousisomorphous seriesseries whichwhich rangerangess inin usinusingg stabilizedstabilized 1,2-dibromomethane1,2-dibromomethane compositioncomposition fromfrom forsteriteforsterite,, Mg2Si04 toto (corrected(corrected forfor temperaturetemperature)) andand anan analyticalanalytical 2 4 fayalite,fayalite, Fe22Si0Si04.• ThThee generalgeneral formulaformula iiss balancbalancee withwith 0.10.1 mgmg sensitivitysensitivity asas wellwell asas thethe (Mg,(Mg, Fe)2Si04'Fe)2SiÖ4. PeridoPeridott lieslies closeclose toto thethe BermanBerman balancebalance.. UltravioletUltraviolet testintestingg waswas forsteriteforsterite endend ofof thethe seriesseries thatthat hashas lowerlower donedone witwithh high-intensithigh-intensityy (100(100 W),W), filtered,filtered, refractiverefractive indicesindices andand specificspecific gravitygravity thanthan mercury-vapoumercury-vapourr lampslamps atat typicatypicall shortshort membermemberss ofof ththee fayalitefayalite end.end. OlivineOlivine isis (253.7(253.7 nm)nm) andand longlong (366.0(366.0 nm)nm) wavelengths.wavelengths. orthorhombicorthorhombic witwithh twtwoo imperfectimperfect cleavagescleavages OpticalOptical spectraspectra werewere observedobserved underunder inin ththee {OlD}{010} andand {lOO}{100} crystal crysta ldirections direction sand and a a darkroomdarkroom conditionsconditions withwith twotwo desk-topdesk-top MohMohss hardnesshardness ofof 6.56.5 ttoo 7.7. Optically,Optically, itit iiss spectroscopespectroscope unitsunits,, oneone withwith a BecBeckk prismprism biaxialbiaxial withwith moderatmoderatee toto highighh birefringence.birefringence. spectroscopespectroscope andand ththee otherother withwith a GIA-GEMGIA-GEM MosMostt ofof thethe materiamateriall collectedcollected aatt BlacBlackk digital-readout,digital-readout, scanning,scanning, diffraction-gratingdiffraction-grating RockRock SummitSummit lavalava flow,flow, thougthoughh largelarge spectroscope.spectroscope. OpticalOptical andand infraredinfrared spectraspectra (30x14(30x14 mm),mm), wawass weathereweatheredd andand erodederoded andand werweree obtainedobtained fromfrom oneone ofof thethe largerlarger (6.4(6.477 ct)ct) quitequite difficultdifficult ttoo removeremove fromfrom ththee matrix.matrix. facetedfaceted specimensspecimens usinusingg a Pye-UnicamPye-Unicam 88088000 SectionedSectioned diamond-sawingdiamond-sawing ofof variousvarious UV-visibleUV-visible spectrophotometerspectrophotometer andand a NicoletNicolet specimensspecimens discloseddisclosed numerousnumerous fracturesfractures 60SX60SX FTIFTIRR spectrometer.spectrometer. radiatinradiatingg fromfrom thethe surfacesurface ofof thethe peridotperidot ChemicalChemical analysesanalyses werewere obtainedobtained byby crystalscrystals resultingresulting inin limitedlimited flaw-freeflaw-free electronelectron microprobmicroprobee andand bbyy proton-inducedproton-induced facetinfacetingg material.material. FacetedFaceted specimensspecimens rangedranged X-raX-rayy emissionemission (PIXE)(PIXE) methods.methods. PIXPIXEE isis a inin weighweightt fromfrom 0.470.47 ctct toto 15.9015.90 ctct.. Peridot fromfrom the Black Rock Summit lava flow, Nye County, Nevada, USAUSA Table I:I: Gemmological properties and chemical compocompo- coulcouldd expecexpectt a zoninzoningg witwithh a magnesiummagnesium- sitions of threethree representativerepresentative samplessamples of Black Rock ricrichh corcoree anandd aann iron-riciron-richh marginmargin.. SucSuchh aa Summit lava flow peridot.peridot. changchangee iinn chemistrchemistryy shoulshouldd bbee reflectereflectedd iinn PropertiesProperties BRP#lBRP#laQ BRP#2BRP#2b BRP#3BRP#3'C coloucolourr anandd refractivrefractivee indexindex,, i.ei.e.. darkedarkerr coloucolourr andalld elementselements anandd highehigherr indiceindicess aatt ththee margimarginn thathann aatt ththee 1 RiRIaa 1.6591.65955 1.651.6588 1.651.6566 | corecore.. IItt wawass thuthuss surprisinsurprisingg ttoo finfindd onlonlyy a slighslightt variatiovariationn iinn refractivrefractivee indiceindicess anandd ~ 1.6721.67255 1.671.6766 1.671.6766 ß littlelittle,, iiff anyany,, correlatiocorrelationn betweebetweenn refractiverefractive YY 1.6931.69300 1.691.6944 1.691.6966 indiceindicess anandd coloucolourr iinn BlacBlackk RocRockk SummiSummitt SSGG n.dn.d.. 3.353.3511 3.383.3888 peridotperidot.. ObserveObservedd refractivrefractivee indeindexx rangerangess werewere:: a = 1.656-1.6601.656-1.660,, ß~ = 1.674-1.6781.674-1.678,, anandd Wt.%Wt.% y = 1.694-1.699,1.694-1.699, witwithh a birefringencbirefringencee rangrangee ooff SiOz 40.55 40.05 37.90 Si02 40.55 40.05 37.90 0.033-0.0380.033-0.038.. MeasurementMeasurementss ofof a,, ß~ andand y onon 1919 AIP3 1.62 0.08 n.d. peridotperidotss ranginrangingg frofromm ververyy lightlight ttoo ververyy darkdark A1203 1.62 0.08 n.d. FeO 10.27 11.79 13.81 colourscolours gavgavee meanmeanss ooff 1.659,1.659,1.67 1.6766 anandd 1.6951.695 FeO 10.27 11.79 13.81 respectively.. ThiThiss woulwouldd indicatindicatee thathatt thertheree iiss MgO 47.43 47.34 47.62 MgO 47.43 47.34 47.62 littllittlee variatiovariationn inin ththee chemistrchemistryy ooff ththee crystalcrystalss MnO 0.16 0.16 0.20 from core to rim and that the chemical MnO 0.16 0.16 0.20 from core to rim and that the chemical iO n.d. 0.28 0.27 analysesanalyses givegivenn inin Table I Iare ar erepresentative representative of of NiO n.d. 0.28 0.27 ththee bulbulkk compositiocompositionn ooff ththee crystalscrystals.. CaO n.d. 0.22 0.15 ' CaO n.d. 0.22 0.15 PleochroisPleochroismm iiss distinctdistinct,, witwithh colourcolour Cr 0 n.d. n.d. 0.034 2 3 combinations for the various colour Cr203 n.d. n.d. 0.034 combinations for the various colour ZnO n.d. n.d. 0.008 categoriescategories of:of: light-greenish-yellowlight-greenish-yellow beinbeingg ZnO n.d. n.d. 0.008 7 Total 100.03 99.92 99.992 Tight-yello'light-yelloww andand lighlightt greenish-yellow'; Total 100.03 99.92 99.992 olive-greenolive-green beingbeing 'medium'medium yellowish-greenyellowish-green 174 94 a and medium orangy-green'; brownish-green 'ChemicalChemical analysisanalysis performedperformed byby M.M. Coiler,Coller, DepartmentDepartment and medium orangy-green'; brownish-green ofof Geology,Geology, IndianaIndiana UniversityUniversity.. (From(From VitalianVitalianoo andand beinbeingg 'medium'medium ttoo darkdark yellowish-greeyellowish-greenn andand Harvey,Harvey 1965.1965.)) mediummedium orangy-brown'orangy-brown' andand finallyfinally ththee darkdark b bElectronElectron microprobemicroprobe analysisanalysis bbyy DaviDavidd E.E. LangLang,, brownbrown beinbeingg 'dark'dark yellowish-brownyellowish-brown andand HarvardHarvard University.University. dark greenish-brown'. Specific gravities of 'AnalysiscAnalysis performedperformed onon thethe PIXEPIXE systemsystem ofof a GeneralGeneral dark greenish-brown'. Specific gravities of IonexIonex Corp.Corp. TandetronTandetron acceleratoraccelerator witwithh anan intenseintense protonproton 3.3513.351 toto 3.3883.388 werewere obtained.obtained. AlAlll specimensspecimens beabeamm ofof upup toto 3MeV,3MeV, a TracorTracor lithium-driftedlithium-drifted siliconsilicon remainedremained inertinert toto bothboth long-long- andand short-waveshort-wave X-rayX-ray detector;detector; andand a multichannelmultichannel analyzeranalyzer system.system. ultravioletultraviolet radiation.radiation. n.d. nonott determineddetermined SpectroscopySpectroscopy andand chemicalchemical NoneNone ofof thethe BlackBlack RockRock SummitSummit peridotperidot compositioncomposition exhibitsexhibits asterismasterism oror chatoyancychatoyancy althoughalthough thesthesee opticaloptical phenomenaphenomena havehave beenbeen reportedreported AbsorptionAbsorption bandsbands werewere observedobserved inin allall inin peridotperidot fromfrom otherother localities.localities. specimensspecimens atat 453,453, 474474 andand 635635 nm,nm, thethe lastlast beingbeing veryvery weak.weak. A moderatelymoderately strongstrong bandband centred at about 495 nm was also observed GemmologicalGemmological propertiesproperties centred at about 495 nm was also observed withwith thethe prismprism spectroscope,spectroscope, bubutt thethe TheThe colourscolours ofof BlackBlack RockRock SummitSummit peridotperidot diffraction-gratingdiffraction-grating unitunit resolvedresolved itit intointo twotwo rangerange fromfrom lightlight yellowish-greenyellowish-green toto oliveolive- bandsbands atat aboutabout 497497 andand 489489 nm. green,green, brownish-greenbrownish-green andand dark-brown.. InIn SpectrophotometrySpectrophotometry ofof thethe 6.476.47 ctct samplesample thethe normalnormal processprocess ofof crystallizationcrystallization ofof a revealedrevealed thesethese andand additionaladditional weakweak bandsbands asas magma,magma, thethe firstfirst olivineolivine toto formform isis highhigh inin follows:follows: 399,399, 403,403, 412,412, 421,, 431431,, 435,435 ,445 445 andand magnesiummagnesium andand asas crystallizationcrystallization proceedsproceeds 530530 nmnm (Figure(Figure 14). 14). As A sone on emight migh texpect, expect ,all al l andand temperaturestemperatures slowlyslowly decrease,decrease, thethe absorptionabsorption bandsbands werewere lessless apparentapparent inin thethe mineralmineral becomesbecomes progressivelyprogressively richerricher inin iron.iron. hand-heldhand-held spectroscopespectroscope inin thethe palerpaler stones.stones. Therefore,Therefore, inin thethe largelarge phenocrysts,phenocrysts, oneone TheThe spectralspectral featuresfeatures havehave allall beenbeen observedobserved J./. Gemm., 1998, 1998,26,2, 26, 2, 86-102 86-102 5.400 ~+------tttttttltt-r 5.000 4.500 4.000 3.500 3.000 2.500 2.000 1.500 0.900 400.00 500.00 600.00 700.00 800.00 900.00 WAVELENGTH (run) Figure 14: UV-visible spectrum spectrum of ofa representativea representative sample sample of peridot of peridot from frommaterial material found foundat Black at Black Rock SummitSummit lava lava flow flow - -a 6.47a 6.47 ct facetedct faceted stone stone (Figure (Figure 13, extreme 13, extreme left of picture) left of picture)and recorded and usingrecorded using a Pye-Unicam 8800 8800 spectrophotometer. spectrophotometer. 95 95 previouslpreviouslyy inin peridoperidott fromfrom otherother localitieslocalities,, recalculatedrecalculated toto oxidesoxides andand thisthis inin turnturn hashas particularlparticularlyy thosethose fromfrom ArizonaArizona (Farrell(Farrell andand beenbeen recalculatedrecalculated toto 100100 perper cent.cent. TheThe newnew NewnhamNewnham,, 1965;1965; Burns,Burns, 1974;1974; Koivula,Koivula, 1981).1981) . analysesanalyses fromfrom thethe microprobemicroprobe andand thethe PIXPIXEE SimilarlySimilarly colouredcoloured peridotperidot frofromm thethe agreeagree wellwell withwith thethe olderolder analysisanalysis (Vitaliano(Vitaliano KilbourneKilbourne HoleHole (Fiihrbach,(Führbach, 1992)1992) showedshowed andand Harvey,Harvey, 1965)1965).. absorptionabsorption bandbandss atat 452,452,47 4733 andand 640640 nm,nm, thethe Yellowish-greenYellowish-green peridotperidot isis a classicclassic lastlast beingbeing relativelrelativelyy weakweak.. A moderatelymoderately exampleexample ofof colorationcoloration byby a transitiontransition metalmetal strongstrong bandband seenseen atat aboutabout 492492 nnmm witwithh thethe ion,ion, inin thisthis casecase Fe2+ (Farrell(Farrell andand Newnham,Newnham, prisprismm spectroscopespectroscope waswas resolvedresolved bbyy thethe 1965),1965), whichwhich producesproduces a seriesseries ofof absorptionabsorption diffraction-gratingdiffraction-grating unitunit intointo bandbandss atat 497497 andand bandsbands visiblevisible inin ththee spectroscope.spectroscope. TracesTraces ooff 489nm.489 nm. chromiumchromium havehave beenbeen reportedreported asas TheThe datadata obtainedobtained byby electronelectron microprobemicroprobe contributingcontributing toto thethe greengreen colourcolour (Arem,(Arem, analysisanalysis andand PIXEPIXE analysesanalyses ofof threethree samplessamples 1987),1987), bubutt nono supportingsupporting datadata forfor thisthis werewere revealedrevealed compositionscompositions typicatypicall forfor peridotperidot foundfound inin BlackBlack RockRock SummitSummit peridot.peridot. (Table 1). I). The Th eMg:Fe Mg:F eratio rati ofor fo r theth eHarvard Harvard SpectrophotometrySpectrophotometry revealedrevealed essentiallyessentially analysisanalysis (omitting(omitting minorminor elements)elements) isis threethree componentscomponents that,that, together,together, leaveleave a . 87.9:12.187.9:12.1 fromfrom aa formula:formula: (Mg(Mgs88gFeFe1212)Si0)Si044. TheThe transmissiontransmission windowwindow centredcentred aroundaround PIXEPIXE analysisanalysis givesgives a ratioratio ofof Mg:FeMg:Fe ofof 86:1486:14.. 550550 nm,nm, whichwhich correspondscorresponds toto yellowishyellowish- TheThe averageaverage ofof threethree analysesanalyses ofof comparablecomparable green.green. TheThe firstfirst ofof thesethese isis anan absorptionabsorption taitaill colouredcoloured materialmaterial fromfrom KilbourneKilbourne HoleHole givesgives thatthat absorbsabsorbs muchmuch ofof thethe redred andand orange.orange. a ratio ofof Mg:FeMg:Fe ofof 88.7:11.388.7:11.3.. ThisThis featurefeature hahass beenbeen observedobserved inin peridotsperidots TheThe PIXEPIXE analysisanalysis givesgives thethe percentagespercentages fromfrom otherother localitieslocalities andand isis relatedrelated toto nearnear- ofof elements;elements; itit reportsreports thethe metalsmetals butbut notnot infraredinfrared absorptionsabsorptions thatthat areare attributedattributed toto oxygen.oxygen. TheThe analysisanalysis asas reportedreported hahass beenbeen Fe2+Fe2+ (Burns,(Burns, 1974)1974).. Peridot fromfrom the Black Rock SummitSummit lavalava flow,flow, Nye County, Nevada, USAUSA TheThe secondsecond componentcomponent isis thethe seriesseries ooff (Weeks(Weeks et at,ah, 1974)1974) and and onon otherother gemgem silicatessilicates bandbandss inin thethe visiblevisible range,range, mostmost ofof whichwhich anandd oxidesoxides (Fritsch(Fritsch andand RossmanRossman,, 1987)1987) havehave alsoalso beebeenn attributedattributed ttoo Fe2+Fe2+ (Farrell(Farrell andand indicatindicatee thatthat thisthis featurfeaturee maymay arisarisee fromfrom Newnham,Newnham, 1965).1965). TheThe suggestionsuggestion thathatt somesome charge-transfercharge-transfer phenomenaphenomena betweenbetween oxygenoxygen araree related toto Mn2+ (Gunawardene,(Gunawardene, 1985)1985) waswas andand transitiontransition metalmetal ions suchsuch asas FeFe3+3+ oorr TiTi4+.4+. nonott substantiated.substantiated. However,However, iron-richiron-rich olivineolivine andand ththee endend TheThe thirdthird spectralspectral componentcomponent isis a generalgeneral membermember fayalitefayalite areare ofteoftenn amber-colouredamber-coloured inin increaseincrease iinn absorptioabsorptionn fromfrom aboutabout 550550 nmnm thinthin sectionsection regardlessregardless ofof TITi contentcontent (Deer(Deer ctet aI., ah, towardtoward ththee ultraviolet,ultraviolet, whichwhich resultsresults inin a 1982,1982, p 186),186), whicwhichh suggestssuggests thatthat FeFe alonealone brownbrown colour.colour. StudiesStudies oonn syntheticsynthetic forsteriteforsterite mamayy bbee responsible. FacetinFacetingg procedurproceduree ThougThoughh perido peridott give givess litu littlee o orr n noo troubl troublee (3(3)) facefacett oonn RayTechRayTech®® 12012000 Nu-BonNu-Bondd DisDiscc durinduringg preformin preformingg o orr cutting cutting,, i tit ca cann b bee ver veryy anandd (4(4)) polis polishh o onn Crystalite Crystalite®® Phenoli Phenolicc LaLapp unpredictablunpredictablee durin duringg polishin polishingg (Varga (Vargass an andd witwithh CrystaliteCrystalite®® 1400140000 MesMeshh ((11 micronmicron)) VargasVargas,, 1989)1989).. BlacBlackk RocRockk SummiSummitt peridoperidott DiamonDiamondd SpraSprayy @@ 202000 ttoo 250r.p.m250 r.p.m.. commonlcommonlyy hahass ononee directiodirectionn inin whicwhichh runninrunningg ththee lalapp damdampp toto nearlnearlyy drydrYi; polishinpolishingg i sis quit quitee difficult difficult.. moderatmoderatee pressure pressure.. Car Caree mus mustt b bee exercise exercisedd AfteAfterr tryin tryingg numerou numerouss combination combinationss o off oonn polishin polishingg wit withh th thee phenoli phenolicc la lapp aass heaheatt lapslaps,, polishin polishingg agent agentss an andd la lapp speeds speeds,, th thee ooff frictio frictionn develop developss rapidl rapidlyy an andd ma mayy causcausee authoauthorr recommendrecommendss ththee followinfollowingg ththee doppin doppingg cemen cementt t oto softesoftenn an andd ththee gemgem procedureproceduress foforr easeasee inin facetinfacetingg anandd toto shiftshift!! polishinpolishingg thi thiss an andd othe otherr perido peridott material material:: WheWhenn al alll els elsee fail failss (a (ass frequentlfrequentlyy happenhappenss 96 (1(1)) prefor preformm o onn Crystalite Crystalite®® 101000 Do Dott Disc Disc,, witwithh peridot peridot)) ususee aa purpuree titinn lalapp witwitl1h halfhalf- 96 (2(2)) face facett o onn Crystalite Crystalite®® 26 2600 Diamon Diamondd Disc Disc,, micromicronn (5 (500 00 0000 meshmesh)) sprayspray diamonddiamond.. Figure 15: Decrepitation haloeshaloes surrounding surrounding MicroscopiMicroscopicc featuresfeatures negative crystals; inclusion features descriptively negative crystals; inclusion features descriptively Thorough examination of several known as 'lily'lily pads' are rarely foundfound inin BlackBlack Thorough examination of several Rock Summit peridot. Photomicrograph byby thousanthousandd specimensspecimens takentaken fromfrom variousvarious J.}. Koivula; 30x. 30x. areas,areas, vizviz.. tumultumulii fromfrom thethe centracentrall lavalava field,field, peripheralperipheral lavlavaa flofloww tumultumulii andand materialmaterial fromfrom thethe lavalava conconee werweree examinedexamined withwith thethe microscope.microscope. FromFrom thesethese somesome 1010 typetypess ooff inclusionsinclusions werweree observed.observed. Lily Pads: althoughalthough ononee expectsexpects ttoo seesee inclusionsinclusions ofof lillilyy padpadss typicaltypical ooff peridotperidot fromfrom otherother sourcessources (Giibelin,(Giibelin, 1974;1974; GiibelinGiibelin andand Koivula,Koivula, 1986),1986), theirtheir nearnear completecomplete absence is i s characteristiccharacteristic ooff BlackBlack RockRock SummitSummit peridot.peridot. InIn fact,fact, ofof mormoree thanthan 3030 facetedfaceted specimensspecimens examinedexamined (0.55(0.55 ctct toto 15.9015.90 ctct)) onlonlyy oneone specimenspecimen containedcontained anan inclusioinclusionn thatthat couldcould bebe describeddescribed asas lillilyy papadd (Figure 15). 15). Geyser-Like: fue th emost mos tfrequently frequentl ynoticed notice d inclusioninclusion inin thethe BlacBlackk RockRock SummitSummit peridotperidot consistsconsists ofof ververyy finefine geyser-likegeyser-like oror finefine hairhair likelike patternspatterns (Figure 16) 16) which which could could not no tbe b e resolvedresolved oror defineddefined aatt magnificatiomagnificationn uupp toto 100xlOOx (Giibelin,(Giibelin, pers.pers. comm.,comm., 1991).1991). /f.. Gemm., 1998,26,1998,26,2, 2, 86-10186-102 Figure 16:16: Since Since these these inclusions inclusions in in BlackBlack Rock Rock Summit Summit peridotperidot have have not not beenbeen seen seen in in otherother worldwide sources sources the the author author has haselected elected to describe to describe the newly the found newly inclusions found inclusions as 'geyser-like' as 'geyser-like' or 'fine or 'fine hair-like' inclusions. inclusions. Photomicrographs Photomicrographs by f. byKoivula; J. Koivula; 30x. 30x. Milky: thethe seconsecondd mostmost encounteredencountered circuitcircuit board)board) inin character.character. ItsIts identityidentity remainsremains inclusioninclusion isis anan overalloverall milkymilky colorationcoloration whichwhich ttoo bebe determineddetermined andand ofof thethe thousandsthousands ooff renderrenderss ththee apparentlapparentlyy flawlessflawless materiamateriall semisemi- specimensspecimens examinedexamined thithiss inclusioninclusion waswas transparenttransparent bbyy transmittedtransmitted lightlight andand hazhazyy inin observedobserved inin butbut twotwo specimensspecimens ofof veryvery darkdark appearanceappearance byby reflectedreflected light.light. browbrownn peridotperidot.. DrDr GiibelinGübelin (pers.(pers. comm.,comm., 1991)1991) Rosary-bead inclusions inclusions (Figure (Figure 17): 17):straight straigh tdescribeddescribe d thethe inclusion(s)inclusion(s) asas '...'... tangletangle ooff andand finefine hair-likhair-likee withwith tinytiny brightbright greengreen regularegularr thread-likethread-like inclusionsinclusions ...... difficultdifficult toto chromechrome diopsidediopside crystals,crystals, partiallypartially resorbed.resorbed. interpretinterpret ...... [possibly [possibly]] thethe edgesedges oror bordersborders ooff 97 PCB: oneone ofof ththee mostmost intriguingintriguing newnew individualindividual grainsgrains ofof a mosaicmosaic structurestructure .... .'/ inclusionsinclusions (Figure 18) 18) was wa sbest bes tdescribed described by by Smoke-like veils: veils: the th eBlack Blac kRock Roc kSummit Summi t GiibelinGübelin (pers.(pers. comm.,comm., 1990)1990) asas PCBPCB (printed(printed containscontains inclusionsinclusions describeddescribed asas smoke-likesmoke-like Figure 17: Tiny chrome diopside inclusions,inclusions, Figure 18:18: This This unusual unusual inclusion inclusion was was found found in in partially resorbed, exhibit exhibit the the low low relief relief and and only twotwo specimens specimens examined examined from from the Black the BlackRock Rock bright green colour typical of this mineral.mineral. Summit peridot and and has has been been best best described described by by Photomicrograph by byf. Koivula;]. Koivula; SOx. 50x. Dr EdwardEdward Cubelin Gübelin as PCBas PCB (printed (printed circuit circuit board) board) in character. Photomicrograph Photomicrograph by E. byCubelin; E. Gübelin; 60x. 60x. Peridot from the Black Rock Summit lava flow, Nye County, Nevada, USAUSA Figure 21:21: Countless Countless dark dark orangy-brown orangy-brown near near- parallel flow flow lines lines in in transmitted transmitted light, light, possibly possibly the result of exsolution. Photomicrograph by by J. Koivula;Koivula; 50x. 50x. Figure 19: Patchy cross-hatched inclusionsinclusions veilsveils similarsimilar toto thosethose previouslypreviously notenotedd iinn foundfound in the Black Rock Rock Summit Summit peridot peridot but but not not peridotsperidots fromfrom ArizonaArizona andand ChinChinaa (Koivula,(Koivula, in peridot fromfrom other other worldwide worldwide sources. sources. This This 1981;1981; GiibelinGübelin andand Koivulq"Koivula , 1986;1986; KoivulaKoivula andand pattern could could only only be be observed observed when when the specimen the specimen Fryer, 1986; Fiihrbach, 1992). They result from 0 Fryer, 1986; Führbach, 1992). They result from was rotated 360360°and and examined examined by by transmitted transmitted incompleteincomplete solidsolid solutionsolution (Koivula(Koivula,, pers.pers. light, and is possibly the result of exsolution. comm.,comm., 1993)1993) thatthat developsdevelops asas ththee peridoperidott iiss Photomicrograph by byJ. Koivula;J. Koivula; 35x. 35x. broughbroughtt toto thethe Earth'sEarth's surfacesurface andand coolcoolss inin thethe Figure 20: 20: Black Black metallic metallic spheres spheres in two in peridotstwo peridots basalt;basalt ; thethe processprocess alsoalso causescauses dislocationsdislocations examined by by dark-field dark-field illumination illumination or transmitted or transmitted whichwhic h produceproduce visiblevisible strainstrain (Kohlstedt(Kohlstedt et al.,al, 98 98 light. When exposed by by careful careful sectioning sectioning they they1976).1976) . TheseThese veilsveils appearappear asas ghostlghostlyy whitewhite reveal crystalline crystalline inclusions inclusions which which were wereidentified identified streamersstreamer s whenwhen viewedviewed withwith darkfieldarkfieldd illumiillumi as pyrrhotitepyrrhotite and and pentlandite. pentlandite. Note Note the variation the variation in nationnatioin n andand appearappear hazyhazy oror milkymilky iinn reflectedreflected colour between the two peridots. Photomicrograph colour between the two peridots. Photomicrograph lightlight renderingrendering thethe gemgem semi-transparent.semi-transparent. by J.J. Koivula; Koivula; 25x 25x and and 40x. 40x. Patchy cross-hatchedcross-hatched inclusions inclusions (Figure (Figure 19): 19): observedobserved bbyy transmittedtransmitted lightlight atat lOlOxx magnification;magnification; thesethese havehave notnot beebeenn observedobserved inin peridoperidott fromfrom otherother sources.sources. Black metallicmetallic spheres: spheres: some som blacke blac opaquek opaqu e sphericalspherical inclusionsinclusions (Figure 20) 20) are are attracted attracted ttoo a magnetmagnet (Koivula,(Koivula, pers.pers. comm.,comm., 1995)1995) andand Figure 22:22: Dendritic Dendritic crystals crystals in in fracturesfractures in in darker brownbrown specimens specimens of Blackof Black Rock Rock Summit Summit peridot; thisthis kindkind ofof inclusion inclusion is is uncommon.uncommon. Photomicrograph by byJ. Koivula;J. Koivula; 15x. 15x. J. Gemm., 1998, 26, 2, 86-10286-102 Table II: Optical and physical properties of peridot from various world sources. Origin RIRl A/). OC SG ReferenceReferellce AntarctiAntarcticc 1.651.6533 ? 1.681.6899 0.030.0366 ? 3.34-3.353.34-3.35 1313 ArizonArizonaa 1.651.6533 1.661.6699 1.691.6900 0.030.0377 8+/-B+/- 3.353.35 4 ArizonArizonaa 1.651.6522 1.671.6711 1.681.6899 0.030.0377 8-B- 3.343.34 4 ArizonArizonaa 1.651.6522 1.661.6688 1.681.6899 0.030.0377 8+B+ 3.343.34 4 ArizonArizonaa (light)(light) 1.641.6499 1.661.6655 1.6861.686 0.030.0377 BB++ 3.283.28 1010 ArizonArizonaa (dark)(dark) 1.651.6533 1.6711.671 1.6911.691 0.030.Q388 B+ 3.383.38 1100 ArizonArizonaa 1.6521.652 1.6701.670 1.6891.689 0.030.0377 BB++ 3.333.33 9 ArgentinaArgentina-* 11.650.650-- 1.670-1.670- 1.688-1.688- 0.030.Q355 B+/-- 33.37-3.4.37-3.444 1818 1.6561.656 1.6751.675 1.6911.691 AustraliAustraliaa 11.65.6533 11.67.6711 1.6901.690 0.030.0377 8B+ 3.393.39 77 BurmBurmaa 1.6541.654 1.6711.671 1.6891.689 0.030.0366 B+ 33.3.322 ]1 BurmBurmaa 1.6561.656 11.67.6711 1.6921.692 0.030.0366 B+/B+/-- 3.353.35 6 ChinChinaa 1.6531.653 1.6701.670 1.6891.689 0.030.0366 8B+ 3.363.36 1919 EthiopiEthiopiaa No datdataa availaavailablblee 2020 KentuckyKentucky"* 1.6691.669 1.6881.688 1.7051.705 0.0360.036 8B-- 33.4.477 1818 KenyKenyaa 1.6501.650 ? 1.6861.686 0.0360.036 ? 3.453.45 1 (yellowish)(yellowish) KenyKenyaa 1.65]1.651 ? 1.6811.681 0.0380.038 ? 3.353.35 11 (brownish)(brownish) Kilbourne 1.659 1.674 1.693 0.034 B+/- 3.42 Kilbourne 1.659 1.674 1.693 0.034 B+/- 3.42 5 (yellowish) (yellowish) Kilboume 1.663 1.679 1.698 0.035 B+/- 3.43 5 Kilbourn(greenish)e 1.663 1.679 1.698 0.035 B+/- 3.43 5 (greenish) Kilbourne 1.669 1.684 1.705 0.Q35 8 +/- 3.50 5 Kilbourn(brownish)e 1.669 1.684 1.705 0.035 B+/- 3.50 5 99 (brownish) 99 evada Nevad(Black aRock) (yellowish)(Black Rock ) 1.659 1.676 1.695 0.036 B+ 3.37 14 (rreeniSh)(yellowish ) 1.6591.659 1.6761.676 1.6951.695 0.0370.036 B+ 3.383.37 1414 ((greenish rownish)) 1.6591.659 1.6761.676 1.6951.695 0.Q380.037 B+B+ 3.393.38 1414 (brownish) 1.659 1.676 1.695 0.038 B+ 3.39 14 ew Mexico 1.652 1.671 1.688 0.036 B- 3.33 1 New Mexico 1.652 1.671 1.688 0.036 B- 3.33 1 Mexico 1.652 1.671 1.688 0.036 B- 3.33 4 Mexico 1.652 1.671 1.688 0.036 B- 3.33 4 Mexico 1.652 1.668 1.685 0.033 B+ ? 4 Mexico 1.652 1.668 1.685 0.033 B+ ? 4 orway 1.650 1.685 0.035 ? ? 2 (cabochon)Norway 1.650 1.685 0.035 ? ? 2 (cabochon) Pakistan 1.651 1.669 1.687 0.036 B+/- 3.35 15,17 Pakistan 1.651 1.669 1.687 0.036 B+/- 3.35 15,17 Sri Lanka 1.651 1.660 1.690 0.039 B+ 3.36 7 Sri Lanka 1.651 1.660 1.690 0.039 B+ 3.36 7 Synthetic 1.65 1.68 0.03 B 3.30 16 Synthetic 1.65 1.68 0.03 B 3.30 16 Tanzania-Kenya 1.650 1.658 1.684 0.034 B+ 3.25 12 (border)Tanzania-Keny a 1.650 1.658 1.684 0.034 B+ 3.25 12 (border) Unknown o data available 11 (cat's-eye)Unknown No data available 11 Viehlam(cat's-eye ) 1.650 ].666 1.688 0.Q38 B+ 3.34 8 ZarbargadVietnam 1.6521.650 1.6681.666 1.6901.688 0.0350.038 BB-+ 3.283.34 78 Zarbargad 1.652 1.668 1.690 0.035 B- 3.28 7 NotesNotes:: OCOC OpticalOptical character.character. 6 Giibelin,Gübelin, 19751975 1414 Fiihrbach,Führbach, 19951995 B BiaxialBiaxial positivepositive oror negative.negative. 7 Gunawardene,Gunawardene, 19851985 1515 Larson,Larson, Thompson,Thompson, 19941994 * PallasiticPallasitic meteoritemeteorite peridotperidot 8 Koivula,Koivula, 19931993 1616 Nassau,Nassau, 19941994 1 Arem,Arem, 19871987 9 Koivula,Koivula, Fryer,Fryer, 19871987 1717 Thompson,Thompson, 19941994 2 Borg,Borg, 19801980 1010 Koivula,Koivula, 19811981 1818 Sinkankas,Sinkankas, Koivula,Koivula, Becker,Becker, 19921992 3 Brown,Brown, Bracewell,Bracewell, 19831983 1111 Kane,Kane, Koivula,Koivula, 19871987 1919 Koivula,Koivula, Fryer,Fryer, 19861986 4 Dunn,Dunn, 19781978 1212 Stockton,Stockton, Manson,Manson, 19831983 2020 Koivula,Koivula, KammerlingKammerling andand 5 Fiihrbach,Führbach, 19921992 1313 Wilson,Wilson, Hendy,Hendy, Taylor,Taylor, 19741974 Fritsch,Fritsch, 19931993 Peridot fromfrom thethe Black Rock Summit lavalava flow,flow, Nye County, Nevada, USAUSA werewere foundfound bbyy X-raX-rayy diffractiondiffraction ttoo bebe facetedfaceted gemsgems andand crystalcrystal inin matrix.matrix. SpecialSpecial pyrrhotitepyrrhotite (Fe1_XS)(FelxS) wherwheree x isis betweenbetween 0.0.00 thanksthanks toto PatriciPatriciaa Robertson-FührbacRobertson-Fiihrbachh forfor andand 0.2.0.2. OtherOther similar-appearingsimilar-appearing spheres,spheres, butbut herher companionshicompanionshipp anandd tirelestirelesss collectingcollecting ooff non-magnetic,non-magnetic, werewere founfoundd ttoo bbee pentlanditepentlandite specimensspecimens anandd especiallyespecially ChrisChris FiihrbachFührbach forfor (Fe,(Fe, Ni)Ni)9Ss'9S8. NotNotee ththee variatiovariationn iinn colourcolour hihiss countlescountlesss hourhourss ooff removinremovingg specimenspecimen betweenbetween ththee twotwo peridotsperidots photographed.photographed. materialmaterial fromfrom thethe lavalava bbyy hammerhammer andand chiselchisel.. Paint-brush strokes: strokes: dark dar orangy-brownk orangy-brow flown flo w lineslines (Figure 21)21) seen seen inin transmittedtransmitted lightligh t ReferencesReferences appearedappeared whitwhitee inin fibre-opticfibre-optic andand dark-fielddark-field illumination.illumination. AlmostAlmost paralleparallell arrangements,arrangements, Anderson,Anderson, B.W.B.W.,, 1971.1971. Gem testing (8th(8th ed).ed). VaVann NostrandNostrand ReinholdReinhold,, NeNeww York,York, 134-63,134-63, 261,261, 293--4293-4 somesome consistingconsisting ofof onlyonly a fewfew lines,lines, otherotherss ooff Arem,Arem, J.E.J.E.,, 1987.1987. Color encyclopedia of gemstones. VanVan severalseveral dozen,dozen, permeatepermeate thethe interiorinterior ooff manymany NostranNostrandd ReinholdReinhold Co.,Co., NeNeww York,York, 137-9137-9 specimens,specimens, regardlessregardless ofof colour.colour. TheyThey areare Bauer,Bauer, M.M.,, 1896.1896. Precious stones. DoveDoverr PublicationsPublications,, Inc.,Inc., possiblypossibly thethe resultresult ofof exsolution.exsolution. IIII,407pp., 407 pp. Borg,Borg, S.,S., 1980.1980. AnAn unusuaunusuall starstar peridot,peridot, Journal of SecondarySecondary inclusionsinclusions inin browbrownn peridotperidot Gemmology, 17(1),17(1), 1-41-4 areare showshownn inin Figure 22. 22. BoschBosch Figueroa,Figueroa, J.M.,J.M., dede llaa FuenteFuente Cullell,Cullell, c.,C., andand ArbunieArbuniess AndresAndres,, M.M.,, 1981.1981. MineralogicaMineralogicall andand gemmologicagemmologicall studystudy ofof olivineolivine fromfrom YaizaYaiza Conclusion (Lanzarote)(Lanzarote).. Gemologia, 14(49-50),14(49-50), 5-185-18 Brenner,Brenner, M.G.M.G.,, 1979.1979. SedimentarySedimentary featuresfeatures iinn basbasee surgesurge BlacBlackk RockRock SummitSummit lavalava flowflow containscontains tuffstuffs,, KilbourneKilbourne HoleHole,, PotrillPotrilloo Mountains,Mountains, DonDon~a AnaAna greatgreat fissurefissuress andand cavitiecavitiess filledfilled witwithh peridot,peridot, CountyCounty,, NewNew MexicoMexico (abs.).(abs.). Geological Society ofof andand partiallpartiallyy resorbedresorbed larglargee peridotperidot crystalscrystals America, Abstracts with Programs, 11(6),11(6), 262677 pp.pp. within the alkali basalt - many exceeding Brown,Brown, G.,G., andand Bracewell,Bracewell, H.,H., 1982.1982. ChudleighChudleigh ParkPark within the alkali basalt - many exceeding peridotperidot.. Australian Gemmologist, 14(10),14(10), 253--6253-6 500500 ctct.. ThoughThough ofof a darkerdarker huehue thanthan peridotperidot Burns,Burns, R.G.R.G.,, 1974.1974. TheThe polarizepolarizedd .-spectraspectra ofof iroironn inin fromfrom otherother worlworldd localitieslocalities,, thethe physicalphysical silicates:silicates: olivine.olivine. A discussiondiscussion ofof neglectedneglected 2z+ 100 100 propertiesproperties andand chemicalchemical compositioncomposition areare contributioncontributionss fromfrom Fe + ionionss iinn MlM1 sites.sites. American Mineralogist, 59, 625-9 consistentconsistent witwithh thosethose forfor peridotperidot (Table II). II). Mineralogist, 59, 625-9 Cahill,Cahill, T.A,T.A., 1980.1980. ProtonProton microprobemicroprobess anandd particleparticle- TheseThese peridotperidotss containcontain newlynewly discovereddiscovered induceinducedd X-raX-rayy analyticalanalytical systems.systems. Ann. Rev. Nucl. Part. inclusionsinclusions whichwhich havhavee nonott beebeenn reportereportedd inin Sci., 211-35211-35 peridotperidot fromfrom otherother worlworldd sources.sources. LilyLily padpad Cavenago-Bignami,Cavenago-Bignami, S.,S., 1972.1972. Six-rayedSix-rayed stastarr peridot.peridot. inclusionsinclusions araree rarelyrarely encountereencounteredd iinn thithiss Gemmologia, 3rd3rd ed.,ed., EditorEditoree UlricUlricoo HoepliHoepli,, Milan,Milan, material. While large specimens as well as 82828pp.8 pp. material. While large specimens as well as Cipriani,Cipriani, c.,C., anandd BorelliBorelli,, A.A,, 1986.1986. Guide to gems and precious cutcut gemgemss areare obtainable,obtainable, thethe extentextent ofof thethe stones. SimonSimon & Schuster,Schuster, Inc.Inc.,, NeNeww YorkYork,, 214-6214-6 materialmaterial availableavailable forfor commercialcommercial purposespurposes Daly,Daly, RS.,R.S., 1914.1914. Igneous rocks andand theirtheir origin.origin. McGrawMcGraw Hill,Hill, hashas nonott yeyett beebeenn estimated.estimated. NeNeww YorYorkk DeerDeer,, W.A,W.A., Howie,Howie, RA,R.A., andand ZussmanZussman,, J.J.,, 1982.1982. 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Ruhle-Diebener-VerlagRuhle-Diebener-Verlag KG,KG, StuttgartStuttgart- isis thankethankedd forfor thethe spectroscopy,spectroscopy, EDXREDXRFF DegerlochDegerloch,, WestWest Germany,Germany, 272-6272-6 Farrell,Farrell, E.E,E.F., andand Newnham,Newnham, R.E.R.E.,, 1965.1965. Crystal-fieldCrystal-field analysis,analysis, andand infraredinfrared spectrometry,spectrometry, andand spectraspectra ooff chrysoberylchrysoberyl,, alexandrite,alexandrite, peridoperidott andand MajaMaja DeMaggioDeMaggio forfor thethe photographsphotographs ofof thethe sinhalite.sinhalite. American Mineralogist, 50(6),50(6), 1972-811972-81 JJ.. Gemm., 1998, 26, 2, 86-10286-102 Fleischer,Fleischer, M.M.,, Wilcox,Wilcox, R.E.,R.E., andand Matzko,Matzko, J.J.,J.J., 19611961.. Koivula,Koivula, J.I.,J.I., Stockton,Stockton, c.,C., andand Fryer,Fryer, C,C., 1980.1980. DiopsideDiopside asas MicroscopicMicroscopic determinationdetermination ofof thethe nonopaquenonopaque anan inclusioninclusion inin peridotperidot.. 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Gems & & Gemology, Gemology, 30(2), 30 (2)102-8, 102- 8 southernsouthern NeNeww MexicMexicoo - GuidebookGuidebook ttoo ththee DesertDesert New Mexico indexindex to to topographic topographic and and other other map map coverage. coverage. ProjectProject.. NewNew MexicMexicoo BureauBureau ofof MinesMines andand MineralsMinerals 1985.1985. Denver.Denver. 38,38, 4422 pp.pp. Resources,Resources, MemoirMemoir 39,39, 222222 pp.pp. New MexicoMexico catalog catalog of topographicof topographic and otherand otherpublished published maps. maps. Gonschorek,Gonschorek, w.,W., 1986.1986. ElectronElectron densitydensity andand polarizedpolarized 19871987 UnitedUnited StatesStates GeologicalGeological Survey,Survey, Denver,Denver, 1515 pp. pp . absorptionabsorption spectraspectra ofof fayalite.fayalite. Physics and and Chemistry Chemistry of of NolanNolan,, L.,L., 1989.1989. PIXE'PIXE* (Proton(Proton Induced Induced X-Ray X-Ray Emission). Emission). 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The Colour Colour treasury treasury of gemstones. of gemstones. Elsevier Elsevier- bearingbearing nodulesnodules andand phenocrystphenocrystss fromfrom basalts.basalts. Phaidon,Phaidon, PhaidonPhaidon PressPress Ltd.,Ltd., London,London, 80-380-3 American Mineralogist, Mineralogist, 50, 501746-82, 1746-8 2 Giibelin,Gübelin, E.,E., 1981.1981. Zabargad:Zabargad: thethe ancientancient peridot islandisland inin Roedder,Roedder, E.,E., andand Weiblen,Weiblen, P.W.,P.W., 1971. 1971. PetrologyPetrology ofof silicatesilicate ththee RedRed Sea.Sea. Gems & & Gemology, Gemology, 17(1), 17(1) 2-8, 2- 8 meltmelt inclusions,inclusions, Apollo 1111 andand Apollo 1212 andand Giibelin,Gübelin, E.,E., 1989.1989. PersonalPersonal communicationcommunication terrestrialterrestrial equivalents.equivalents. ProceedingsProceedings ofof thethe SecondSecond Giibelin,Gübelin, E.J.E.J.,, andand KoivulaKoivula,, J.I.,J.I., 1986.1986. PhotoatlasPhotoatlas of ofinclusions inclusions LunarLunar ScienceScience Conference,Conference, M.I.T.M.I.T. Press,Press, 1,1, 507-28507-28 in gemstones.gemstones. ABC AB CEdition, Edition Zurich,, Zurich 305-8, 305- 8 Roedder,Roedder, E.,E., 1976.1976. PetrologiPetrologicc datadata fromfrom experimentalexperimental Gunawardene,Gunawardene, M.,M., 1985.1985. PeridotPeridot fromfrom RatnapuraRatnapura DistrictDistrict,, studiesstudies onon crystallizedcrystallized silicatesilicate meltmelt andand otherother 101101 SriSri Lanka.Lanka. Journal of of Gemmology, Gemmology, 19(8), 19 (8)692-702, 692-70 2 inclusionsinclusions inin lunarlunar andand HawaiianHawaiian olivine.olivine. American Hodgman,Hodgman, CD.,C.D., 1950.1950. Handbook of of chemistry chemistry and and physics. physics. Mineralogist, 61, 61 684-90, 684-9 0 ChemicalChemical RubberRubber PublishingPublishing Co.,Co., Cleveland,Cleveland, OhioOhio,, Seager,Seager, W.R.,W.R., 1987.1987. Caldera-like collapse collapse at Kilbourneat Kilbourne Hole Hole USA,USA, 1818-241818-24 maar, New New Mexico. Mexico. New Ne Mexicow Mexic Geology,o Geology University, Universit ofy of Hoffer,Hoffer, J.M.,J.M., 1976.1976. GeologyGeology ofof PotrilloPotrillo basaltbasalt field,field, southsouth- NeNeww Mexico,Mexico, Albuquerque,Albuquerque, 69-7369-73 centralcentral NeNeww Mexico,Mexico, NewNew MexicoMexico BureauBureau ofof MinesMines Seager,Seager, w.R.,W.R., Shafiqullah,Shafiqullah, M.,M., Hawley,Hawley, J.w.,J.W, andand Marvin,Marvin, R,R., andand MineraMinerall ResourcesResources,, CircularCircular 149,149, 3030 pp.pp. 1984.1984. NewNew K-ArK-Ar datesdates fromfrom basaltsbasalts andand thethe evolutionevolution ofof Hurlbut,Hurlbut, C.S.,C.S., Jr.,Jr., 1979.1979. Gemology. John Joh nWiley Wile &y &Sons, Sons New, Ne w thethe southernsouthern RioRio GrandeGrande rift.rift. GeologicalGeological Society Society of America of America YorkYork,161-3, 161-3 Bulletin, 95, 95 87-99, 87-9 9 Kammerling,Kammerling, R.C.R.C,, 1993.1993. PeridotPeridot fromfrom Ethiopia.Ethiopia. Gems && Shaub,Shaub, B.M.,B.M., andand Shaub,Shaub, M.S.,M.S., 1975.1975. Treasures from from the the Gemology, 29(1), 29(1) 59, 5 9 Earth: the world of rocks and minerals. CrownCrown Kane,Kane, R.E.,R.E., Koivula,Koivula, J.I.,J.I., 1987.1987. Peridot,Peridot, cat's-eye.cat's-eye. Gems && Publishing,Publishing, Inc.,Inc., NeNeww York,York, 192192 pp.pp. Gemology, 23(2), 23(2) 106, 10 6 Shoemaker,Shoemaker, E.M.,E.M., 1957.1957. PrimaryPrimary structuresstructures ofof maarmaar rimsrims KellerKeller,, AS.,A.S., andand Kammerling,Kammerling, R.C,R.C., 1993.1993. PeridotPeridot fromfrom andand theirtheir bearinbearingg onon thethe originorigin ofof KilbourneKilbourne HoleHole andand Vietnam.Vietnam. Gems & & Gemology, Gemology, 29(3), 29(3) 211-2, 211- 2 ZuniZuni SaltSalt Lake,Lake, NewNew MexicoMexico (abs).(abs). Geological Society Society of of King,King, W.E.,W.E., HawleyHawley,, J.W.J.w.,, Taylor,Taylor, AM.,A.M., andand WilsonWilson,, R.P.R.P.,, America Bulletin, Bulletin, 68, 68 1864, 186 4 1983. Hydrologic ReportReport 1:1: GeologyGeology and and groundwater ground Sinkankas,Sinkankas, J.,J., 1959.1959. Gemstones of of North North America, America, Vol. Vol 1. Van. 1. Va n water resourceresourcess ooff centralcentral andand westernwestern DonaDona AnaAna NostrandNostrand ReinholdReinhold Company,Company, NewNew York,York, 206-7206-7 County,County, NewNew MexicoMexico,, StateState BureauBureau of.of MineMiness andand Sinkankas,Sinkankas, J.,J., 1961.1961. Gemstones and minerals. D.D. VanVan MineralMineral Resources,Resources, NewNew MexicoMexico InstituteInstitute ofof MiningMining NostranNostrandd Co.,Co., Inc.,Inc., NewNew York.York. 206206 pp.pp. and Technology, Socorro, Socorro, Abstract, Abstract, 23, 23 59, 59 Sinkankas,Sinkankas, J.,J., 1976.1976. GemstonesGemstones of ofNorth North America. America. Vol. VolII. Van. II. Van Kohlstedt,Kohlstedt, D.L.D.L.,, Goetze,Goetze, C,C., Durham,Durham, W.B.,W.B., andand VanderVander NostrandNostrand ReinholdReinhold Company,Company, NewNew York,York, 114-5114-5 Sande,Sande, J.J.,, 1976.1976. NeNeww techniquetechnique forfor decoratingdecorating Sinkankas,Sinkankas, J.,J., KoivuIa,Koivula, J.1., J.I. ,and and Becker,Becker ,G., G. , 1992.1992 .Peridot Peridot as as dislocationsdislocations inin olivineolivine.. Science, 191, 191 104~, 1045- 6 anan interplanetaryinterplanetary gemstone.gemstone. Gems && Gemology, Gemology, 28(1), 28(1) , KoivuIa,Koivula, J.I.,J.I., 1981.1981. SanSan CarloCarloss peridot.peridot. Gems && Gemology, Gemology, 43-5143-51 17(4),205-1417(4), 205-14 Smith,Smith, G.H.,G.H., 1958.1958. Gemstones. Pitman Pitma nPublishing Publishin gCorp., Corp. , Koivula,Koivula, J.I.J.I.,, 1993.1993. PeridotPeridot fromfrom Vietnam.Vietnam. Gems & NewNew York,York, 347-51347-51 Gemology, 29(3), 29(3) 211-12, 211-1 2 Smith,Smith, RL.,R.L., andand Luedke,Luedke, RG.,R.G., 1984.1984. PotentiallyPotentially activeactive Koivula,Koivula, J.I.,J.I., andand FryerFryer,, Cw.,C.W., 1987.1987. ChalcopyriteChalcopyrite inin volcanicvolcanic lineamentslineaments andand lociloci inin westernwestern coterminouscoterminous peridot:peridot: a firstfirst observationobservation.. Journal ofof Gemmology, Gemmology, UnitedUnited States:States: inin Explosive Volcanism: Volcanism: Inception, Inception, Evolution, Evolution, 20(5),272-320(5), 272-3 Hazards. Nat!. Natl Acad.. Acad Press,. Press Washington,, Washington DC,, DC 47-66, 47-6 6 Peridot from from the the Black Black Rock Rock Summit Summit lava flow,lava flow,Nye County, Nye County, Nevada, Nevada, USA USA Stockton,Stockton, E.M.,E.M., anandd Manson,Manson, D.V.,D.V., 1983.1983. PeridotPeridot fromfrom Tanzania.Tanzania. Gems & Gemology, 19(2),19(2), 103-7103-7 Stuart,Stuart, e.J.,C.J., 1981.1981. Hunt'sHunt's HolHolee maarmaar volcano,volcano, DonaDona AnaAna County,County, south-centralsouth-central NeNeww MexicoMexico andand geologygeology ofof thethe borderborder,, southernsouthern NewNew Mexico-northernMexico-northern Chihuahua.Chihuahua. El Paso Geological SocietySociety Guidebook, Guidebook, 64-72 64-72 Stuart,Stuart, C.J.e.J.,, andand BrennerBrenner,, M.G.M.G.,, 1979.1979. 'Lo'Logg Regime'Regime' basebase surgesurge dunesdunes - aann exampleexample fromfrom KilbourneKilbourne anandd Hunt'sHunt's HolesHoles,, south-centralsouth-central NeNeww MexicoMexico (abs.).(abs.). GeologicalGeological Society of America, Abstracts with Programs, 11(7),11(7), 525525 ThompsonThompson,, L.,L., 1994.1994. MoreMore onon peridoperidott frofromm Pakistan.Pakistan. Gems & Gemology, 30(4),30(4), 275275 Thompson,Thompson, L.,L., anandd Larson,Larson, B.,B., 1994.1994. PeridotPeridot fromfrom Pakistan.Pakistan. Gems & Gemology, 30(3),30(3), 196196 UniteUnitedd StatesStates GeologicalGeological Survey,Survey, 1968.1968. BlackBlack RockRock Summit,Summit, NevadaNevada (Map),(Map), SWSW/ /44 PortuguesePortuguese Mtn.Mtn. 1515'' Quadrangle,Quadrangle, N3830-W11552.5/7.5N3830-W11552.5/7.5,, UUSS GeologicalGeological A. W GUS LWand Survey,Survey, DenverDenver SW lamp (220/24Ov) UnitedUnited StatesStates GeologicalGeological Survey,Survey, 1967.1967. LunarLunar Crater,Crater, Hand-held mains NevadNevadaa (Map),(Map), NE/4NE/4 LunaLunarr CraterCrater 15'15' Quadrangle,Quadrangle, N3822.N3822.5--W11600/7.5,5 W11600/7.5, UUSS GeologicalGeological Survey,Survey, DenverDenver unit with 4 watt tubes. UnitedUnited StatesStates GeologicalGeological Survey,Survey, 1967.1967. MooreMooress StationStation SE,SE, WlOOOl NevadNevadaa (Map),(Map), SE/4SE/4 MooresMoores StationStation 15'15' Quadrangle,Quadrangle, Usual Price £215.00· N3830-W11600/7.5,N3830-W11600/7.5, UUSS GeologicalGeological Survey,Survey, DenverDenver UniteUnitedd StatesStates GeologicalGeological Survey,Survey, 1985.1985. Nevada/IndeNevada/Indexx toto topographitopographicc anandd otherother mapmap coverage.coverage. UUSS DepartmentDepartment ofof ththee Interior,Interior, GeologicaGeologicall Survey,Survey, RestonReston UniteUnitedd StatesStates GeologicalGeological Survey,Survey, 1968.1968. TheThe Wall,Wall, NevadaNevada (Map),(Map), NWNW/ /44 TheThe WallWall 15'15' Quadrangle,Quadrangle, N3822.5-W2552.5/7.5N3822.5-W2552.5/7.5,, UUSS GeologicalGeological Survey,Survey, DenverDenver A {3:> 102 Vargas,Vargas, G.,G., andand Vargas,Vargas, M.M.,, 1989.1989. Faceting forfor amateurs.amateurs. 3rd3rd 102 ed.ed. DeserDesertt PrintingPrinting Company,Company, Indio,Indio, California,California, 271271 pp.pp. VitalianoVitaliano,, e.J.,C.J., andand Harvey,Harvey, R.D.R.D.,, 1959.1959. BlacBlackk RocRockk SummitSummit basaltbasalt flow,flow, NevadaNevada.. Geological Society of America Bulletin, 70(2),70(2), 1691-21691-2 Vitaliano,Vitaliano, C.J.e.J.,, andand Harvey,Harvey, R.D.,R.D., 1965.1965. AlkalAlkalii basaltbasalt fromfrom NyeNye County,County, NevadaNevada.. American Mineralogist, 5050,, 73-8473-84 B. lW and SW UV Portable lamp WalkerWalker,, G.p.L.,G.P.L., 1991.1991. StructureStructure andand originorigin bbyy injectioninjection ooff Portable lamp with a slide baffle to lavlavaa underunder surfacesurface crustcrust ofof tumuli,tumuli, 'lava'lava rises',rises', 'Iava'lava- switch easily from lW to SW. Uses four riserise pitspits'' andand 'lava-inflatio'lava-inflationn clefts'clefts' inin HawaiiHawaii.. Bull. M batteries (not supplied). UVl0006 Volcanology, 53,53 , 546-58546-58 WebsterWebster,, R.R.,, 1975.1975. Gems, their sources, descriptions and Usual Price £55.00· identification. 3rd3rd ed.ed. Butterworths,Butterworths, London,London, 133-41,133-41, 279-82,314,577-81279-82, 314, 577-81 Special Offer £44.00* WeeksWeeks,, R.A.,R.A., Pigg,Pigg, J.e.,J.C., andand Finch,Finch, C.B.e.B.,, 1974.1974. ChargeCharge- 3+ 2+ transfertransfer spectraspectra ofof Fe3+ anandd Mn2+ iinn syntheticsynthetic forsteriteforsterite (Mg SiO )).. American Mineralogist, 59 (11 and 12), Special offer ends (Mg2Si04 American Mineralogist, 59 (11 and 12), 1259--{i61259-66 30 June 1998 Wilson,Wilson, A.T.,A.T., HendyHendy,, e.H.,C.H., anandd Taylor,Taylor, A.M.,A.M., 1974.1974. PeridotPeridot onon RosRosss IslandIsland - Antarctica.Antarctica. Australian Gemmologist,Gemmologist, 14(4),12414(4), 124 ~Price shown exclude VAT, WoodWood,, e.A.,C.A., andand Kienle,Kienle, J.J.,, 1990.1990. LunarLunar CraterCrater (Nevada).(Nevada). postage and packing Volcanoes of North America/United States and Canada. CambridgeCambridge UniversitUniversityy PressPress,, NeNeww YorkYork,, 258-9258-9 Gemmological Instruments Limited, Showroom: 27 Greville Street (Saffron Hill entrance), London Eel N 8SU . Tel : 0171 ·404 3334 Fax: 0171 -404 8843 J.J. Gemm., 1998, 26, 2, 86-10286-102 Rubies and pink sapphires from the Pamir Mountain Range in Tajikistan, former USSR Christopher P. Smith Managing Director; Special Projects, Gübelin AG, Lucerne, Switzerland ABSTRACT: A small number of gem-quality rubies and pink sapphires are being recovered from marble-type deposits in the Pamir mountains of the Republic of Tajikistan, southern portion of the former USSR. Presented in detail are the standard gemmological properties and internal features of a few samples from this remote locality. Some distinctive inclusion patterns were noted and a variety of mineral inclusions were identified. In addition, the spectral characteristics and chemical composition of the samples are provided. Keywords: corundum, ruby, sapphire, Pamir mountains, Tajikistan, USSR, gemmological properties 103 Introduction early 1980s. Since their discovery, a limited supply of these rubies has entered the he Pamir mountain range traverses gemstone trade. Tajikistan, along the southern region Tof the former Soviet Union, bordering Turakuloma is the name of the ruby- Afghanistan and China. This mountain producing region (I. Pojarevski and A. Trushin, sequence is well known to professional and 1997, pers. comm.) and is located about 6 km hobbyist mountain climbers for its beautiful from the Chinese border and about 40 km NE and challenging topography. The mountains of the town of Murgab (Henn and Bank, 1990; are relatively unknown, however, to most Henn et al, 1990). Within this region several gemmologists around the world as a source mines have been worked, the richest and best of gemstones. The most recognized gems are known being Snejnaya at an elevation of about the red spinels from along the eastern 3500 m. The mines are typically worked from portion near the border with China (Koivula June until August - the weather conditions are and Kammerling, 1989); however, these too harsh during the rest of the year. In general mountains also produce limited quantities of about 30 people work each mine using picks gem-quality clinohumite, tourmaline, topaz, and shovels, but at some, such as at Snejnaya, danburite, scapolite, jeremejevite and dynamite and a bulldozer are also used to corundum (Henn and Bank, 1990). recover the gems (I. Pojarevski and A Trushin, 1997, pers. comm.). Rubies from the Pamir mountains were first described by Henn and Bank (1990) and Samples, methods and equipment Henn et al (1990). Therein, these researchers described a marble-type deposit which was This brief description of the rubies and first discovered by a Soviet geologist in the pink sapphires from the Pamir mountains is © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355-4565 thethe resultresult ofof anan investigationinvestigation ofof eighteight gemstonesgemstones (ranging(ranging inin weightweight fromfrom 0.300.30 cctt toto 1.481.48 ct),ct), whicwhichh werweree obtainedobtained fromfrom IvanIvan Pojarevski,Pojarevski, presidenpresidentt ofof BulgariBulgariaa Gems,Gems, Sofia,Sofia, BulgariaBulgaria,, andand frofromm otherother dealersdealers specializingspecializing inin gemsgems fromfrom ththee PamirPamir region.region. TheThe samplessamples werweree purchasedpurchased fromfrom minersminers workingworking directlydirectly withinwithin ththee corundumcorundum depositsdeposits ofof thethe PamiPamirr mountainmountain range.range. A binocularbinocular microscopemicroscope combinedcombined withwith fibre-opticfibre-optic lightinglighting techniquestechniques waswas usedused ttoo examineexamine internainternall andand externalexternal characteristics.characteristics. A DuplexDuplex IIII refractometerrefractometer waswas usedused toto measurmeasuree ththee refractiverefractive indices,indices, asas wellwell asas deterdeter minemine thethe birefringencebirefringence andand opticoptic character.character. SpecificSpecific gravitgravityy determinationsdeterminations werweree mademade withwith a MettleMettlerr electronicelectronic balancbalancee equippedequipped witwithh thethe appropriateappropriate attachmentsattachments forfor hydrohydro Figure 1: Gem-quality rubies and pink sapphires fromfrom the Pamir mountains inin staticstatic weighweightt measurements.measurements. Long-waveLong-wave Tajikistan. The samples range from 0.30 toto (365(365 nm)nm) andand short-waveshort-wave (25(2544 nmnm)) lampslamps werweree O.SO0.80 ct, with such qualities typically being found usedused ttoo testestt ththee ultravioleultraviolett fluorescentfluorescent reacreac in sizes up to one and a half carats. PhotographedPhotographed tionstions andand a calcitecalcite dichroscopedichroscope waswas used ttoo by Nicole Surdez.Surdez. observobservee ththee pleochroism.pleochroism. 104104 Table I:I: TheThe gemmological gemmological properties properties of the of rubies the rubies and pink and sapphires pink sapphires from the fromPamir the Mountain Pamir MountainRange, Republic Range, Republic of Tajikistan. VisuaVisuall appearancappearancee HighlHjghlyy transparentransparentt witwithh richlrichlyy saturatesaturatedd huehuess rangingranging fromfrom purplish-pinpurpHsh-pinkk ttoo purplish-repurpHsh-redd RefractivRefractivee indeindexx Nee == 1.761-1.761.761-1.7622 No0 = 1.771.7700 BirefringencBirefringencee 0.008-0.000.008-0.0099 OptiOpticc charactecharacterr UniaxiaUruaxiall negativnegativee SpecifiSpecificc gravitgravityy 3.99-4.03.99-4.022 PleochroisPleochroismm ModeratModeratee ttoo stronstrongg dichroismdichroism;; Pinkish/reddish-orangPinkish/reddish-orangee ttoo red-orangred-orangee paralleparallell ttoo ththee c-axic-axiss Purple-pinPurple-pinkk ttoo purple-repurple-redd perpendiculaperpendkularr ttoo ththee c-axic-axiss UUVV luminescencluminescencee Long-wavLong-wavee (36(3655 nm)nrn):: stronstrongg ttoo ververyy strongstrong,, slightlsHghtlyy orangy-orangy- reredd ttoo reredd Short-wavShort-wavee (25(2544 nm)nrn):: ververyy weaweakk ttoo mediumeruurnm reredd Visible absorption spectrum General absorption up to apprOXimately 450 nrn; 468, 475 and Visible absorption spectrum Genera476 nrnl Hnes;absorptio broadn u bandp to approximatelbetween approximatelyy 450 nm; 468,47530-5805 annrn;d 47659,6926 nm lines and; 694broa nrnd ban Hnesd between approximately 530-580 nm; 659,692 and 694 nm lines Internal features Very fine clouds, short rutile needles and pinpoint particles, faint Internal features Verto moderatelyy fine clouds distinct, short growthrutile needle structures,s and pinpoinoccasionallyt particles faint , faint tcolouro moderatel zoning,y distinc twin lameUae,t growth mineralstructures or, negative occasionall crystalsy fain twith colouorientedr zoning equatorial, twin thIDlamellae films, minera- singlyl oorr negativ aJjgnede incrystal rows,s variouswith orientehealedd fracture equatoria patterns,l thin film 2- ands - singl 3-phasey or negative aligned icrystals,n rows, variouas weUs healeas crystallined fractur einclusions patterns, of2- calcite,and 3-phas titanite,e negativ zircon,e crystals rutile and, as well aplagioclases crystallin efeldspar inclusion s of calcite, titanite, zircon, rutile and plagioclase feldspar }J.. Gemm., 1998,26,2,1998,26,2,103-109 103-109 c=----_c - ____ oowfu woo/u 00oo/11v 105105 00oo/11u 00oo/11u 00oo/11u Figure 2: Two dipyramidaldipyramidal crystalcrystal habitshabits werewere identified identified in in rubies rubies and and pink pink sapphires sapphires originating originating from from the Pamir Mountains: (a) habits composed of subordinate basal pinacoid^pinacoid c c(0001) (0001) and and positive positive rhombohedral r r(1011) (1011) crystal crystal faces faces and and dominant dominant 0)c.o c o(14 (14 14 14 28 28 3) 3) or or v v (4481) (4481) crystal crystal fac~s,fac!!.s, faces, and and (b) (b) Habits composed of subordinate basal pinacoidpjnacoid c (0001) and positive rhombohedral r r (10 (1011) 11) crystal crystal faces, withwith dominantdominant dipyramidaldipyramidal zz (2241)(2241) crystalcrystal faces.faces . Rubies and pink sapphires from the the Pamir Pamir MountainMountain RangeRange in in Tajikistan,TajikistanTajikistan,, former former USSR USSR TheThe internalinternal growthgrowth characteristicscharacteristics werewere pinkpink sapphiressapphires inin generalgeneral (Liddicoat,(Liddicoat, 19891989;; classifiedclassified usingusing a speciallyspecially designeddesigned stonestone- HurlbutHurlbut andand Kammerling,Kammerling, 1991;1991; Webster,Webster, holderholder andand immersionimmersion microscopemicroscope 1994;1994; Hughes,Hughes, 1996)1996).. incorporatingincorporating thethe techniquestechniques describeddescribed byby SchmetzerSchmetzer (1985,(1985, 1986),1986), KiefertKiefert andand Internal growth structures, colour zoningzoning SchmetzerSchmetzer (1991)(1991) andand SmithSmith (1996).(1996). TheThe and twinningtwinning variousvarious mineralmineral inclusionsinclusions werewere identifiedidentified FaintFaint toto moderatemoderate linearlinear andand angularangular usingusing a scanningscanning electronelectron microscopemicroscope growthgrowth structuresstructures werewere observedobserved parallelparallel ttoo equippedequipped witwithh anan energy-dispersiveenergy-dispersive X-rayX-ray thethe dipyramidaldipyramidal (0co (14(14 14 14 283) 28 3 )or or v v (4481) (4481 )and and fluorescence unit (SEM-EDS). Absorption fluorescence unit (SEM-EDS). Absorption positivepositive rhombohedralrhombohedral r (1011)(lOTl) crystalcrystal faces.faces. A spectra were taken with a standard desk spectra were taken with a standard desk- dipyramidaldipyramidal crystalcrystal habithabit composedcomposed ooff model spectroscope and a UV-Vis-NIR model spectroscope and a UV-Vis-NIR subordinatesubordinate c (0001)(0001) andand r (1011),(10Ï1), withwith PerkinPerkin ElmerElmer LamdaLamda 9 spectrometerspectrometer withwith a dominant (0co (14(14 1414 2828 3)3) oror v (4481)(4481) crystalcrystal beam condenser and polarising filters in the beam condenser and polarising filters in the faces,faces, maymay thereforetherefore bebe consideredconsidered asas typicaltypical regionregion betweenbetween 200200 andand 800800 nm.nm. InfraredInfrared forfor thethe rubiesrubies andand pinkpink sapphiressapphires fromfrom thethe spectraspectra inin thethe regionregion betweenbetween 400400 andand 70070000 -1 PamirPamir mountains.mountains. TheThe authorauthor waswas alsoalso shownshown wavenumberswavenumbers (cm-(cm 1 )) werewere takentaken withwith aa PyePye- a smallsmall pinkpink sapphiresapphire crystal,crystal, reportedlyreportedly fromfrom Unicam FTIR 9624 spectrometer using a Unicam FTIR 9624 spectrometer using a ththee samesame localitylocality iinn thethe PamirPamir mountains,mountains, diffuse reflectance unit. A semi-quantitative diffuse reflectance unit. A semi-quantitative whichwhich possessedpossessed a subordinatesubordinate basabasall pinacoidpinacoid chemical analysis was performed with a chemical analysis was performed with a c (0001)(0001) andand positivepositive rhombohedralrhombohedral r (lOTl)(1011),, SpectraceSpectrace TNTN 50005000 systemsystem energy-dispersiveenergy-dispersive withwith dominantdominant dipyramidaldipyramidal z (2241)(2241) crystalcrystal X-ray fluorescence spectrometer. X-ray fluorescence spectrometer. facesfaces (Figure 2). 2). Although Although in in general genera lthe th ePamir Pami r samplessamples areare homogeneouslyhomogeneously coloured,coloured, oneone VisualVisual appearanceappearance samplesample alsalsoo displaysdisplays a palepale pinkpink columnarcolumnar zone bordered by darker pink sapphire with 106 TheThe samplessamples inin thisthis studystudy areare transparenttransparent zone bordered by darker pink sapphire with 106 slightly irregular growth structures. Lamellar andand displaydisplay richlyrichly saturatedsaturated colourscolours rangingranging slightly irregular growth structures. Lamellar twin planes parallel to a single positive fromfrom purplish-pinkpurplish-pink toto purplish-redpurplish-red (Figure 1). 1). twin planes parallel to a single positive rhombohedralrhombohedral r (1011)(10Ï1) planeplane werewere alsoalso observedobserved (Figure 3). 3). PropertiesProperties Gemmological propertiesproperties Inclusion features TheThe refractiverefractive indices,indices, birefringence,birefringence, opticoptic AlthougAlthoughh thethe samplingsampling ofof ththee rubiesrubies andand character,character, specificspecific gravity,gravity, UVUV fluorescencefluorescence pinkpink sapphiressapphires fromfrom thethe PamirPamir mountainsmountains reactionreaction andand pleochroismpleochroism areare summarizedsummarized inin waswas small,small, theythey providedprovided anan interestinginteresting arrayarray Table I Iand and arear econsistent consisten t withwith rubiesrubie s andand ofof inclusions.inclusions. MostMost commonly,commonly, thesethese consistedconsisted Figure 3: Twin planes parallel toto the the positive positive Figure 4: Short rutile needles and pinpointpinpoint rhombohedron r (1011)r (1011) in ain Pamir a Pamir ruby. ruby. Fibre Fibre-particles inin a a columnar columnar pattern, pattern, distinctive distinctive of of optic illumination,illumination, 35x. 35x. Pamir rubies.rubies. Fibre-optic Fibre-optic illumination, illumination, 35x. 35x. J. Gemm., 1998,1998,26,2,103-109 26, 2, 103-109 Figure 5: Calcite crystals, highly resorbed, in parallel rowsrows form form aa distinctive distinctive inclusioninclusion patternpattern in the rubies and pink sapphires from Pamir. Fibre-optic illumination,illumination, 40x.40x. ofof veryvery finefine whitishwhitish toto bluish-whitebluish-white clouds,clouds, Figure 6: Oblong transparent, colourless wherewhere thethe individualindividual pinpointpinpoint particlesparticles werewere crystals of plagioclase feldspar in a 0.80 ct notnot identifiable.identifiable. InIn sufficientsufficient concentration,concentration, purplish-pink sapphire from Pamir. Fibre-opticFibre-optic suchsuch cloudsclouds occasionallyoccasionally instilledinstilled a slightlyslightly illumination, 48x.48x. hazyhazy appearance.appearance. InIn addition,addition, shortshort veryvery finefine rutilerutile needlesneedles andand particlesparticles populatedpopulated thethe notednoted andand distinctivedistinctive idiomorphicidiomorphic negativenegative samples,samples, andand inin somesome stonesstones formedformed a crystalscrystals oftenoften containedcontained immiscibleimmiscible liquidliquid andand distinctivedistinctive columnarcolumnar patternpattern (Figure 4).4). gasgas phasephasess (Figure 8).8). A varietyvariety ofof largerlarger crystallinecrystalline inclusionsinclusions werewere alsoalso identified.identified. TheThe mostmost plentifuplentifull werewere Absorption spectraspectra 107107 distinctlydistinctly rounded,rounded, irregularirregular massesmasses ooff TheThe spectraspectra ofof thethe rubiesrubies andand pinkpink transparenttransparent calcite.calcite. TheseThese consistedconsisted ofof highlyhighly sapphiressapphires fromfrom thethe PamirPamir mountainsmountains areare resorbedresorbed platyplaty crystalscrystals whichwhich werewere dominateddominated byby Cr3+Cr3+ absorption,absorption, withwith broadbroad predominantlpredominantlyy equidimensionalequidimensional toto oblongoblong inin bandsbands centredcentred atat approximatelyapproximately 405405 andand formform andand whichwhich werewere occasionallyoccasionally 550550 nm,nm, andand weakweak toto moderatemoderate sharpsharp bandbandss atat accompaniedaccompanied byby thinthin films.films. CommonlyCommonly thethe approximatelyapproximately 468468,, 475,475, 476,476, 659,659, 692692 andand calcitecalcite crystalscrystals werewere presentpresent inin distinctive,distinctive, 694694 nm.nm. SuchSuch absorptionabsorption characteristicscharacteristics areare roughlyroughly paralleparallell formationsformations (Figure 5). PalePale typicaltypical ofof rubiesrubies andand pinkpink sapphiressapphires inin generalgeneral yellowyellow crystalscrystals ofof titanitetitanite (sphene)(sphene) typicallytypically (see(see e.g.e.g. Liddicoat,Liddicoat, 1989;1989; Hughes,Hughes, 1996)1996).. occurredoccurred asas tinytiny roundedrounded crystals,crystals, althoughalthough largerlarger moremore irregularirregular formsforms werewere alsoalso Figure 7: Aligned rows of small mineral or identified.identified. SmallSmall prismaticprismatic zirconzircon crystalscrystals negative crystals, each being accompanied by an witwithh a length-to-widthlength-to-width ratioratio ofof approxiapproxi oriented thin film. Such inclusions also occurredoccurred matelmatelyy 3:13:1 occurredoccurred singlysingly andand oneone waswas ideniden singly. Fibre-optic illumination, SOx.50x. tifiedtified intergrownintergrown withwith a largerlarger irregularirregular sphenesphene crystal.crystal. ColumnarColumnar crystalscrystals ofof rutilerutile werewere eithereither a vibrantvibrant orangeorange oror blackblack,, andand oblongoblong crystalscrystals ofof plagioclaseplagioclase feldsparfeldspar werewere alsoalso identifiedidentified (Figure 6). AnotherAnother unusuaunusuall inclusioninclusion featurefeature consistedconsisted ofof alignedaligned rowrowss ofof smallsmall mineralmineralss oror negativnegativee crystals,crystals, wherewhere eacheach crystalcrystal waswas accompaniedaccompanied byby anan orientedoriented equatorialequatorial thinthin filmfilm (Figure 7).7). TheseThese inclusionsinclusions alsoalso occurredoccurred singly.singly VariousVarious healehealedd fracturefracture patternspatterns werewere Rubies and pink sapphires fromfrom thethe PamirPamir MountainMountain RangeRange inin Tajikistan,Tajikistan, former former USSRUSSR Table 1/: II: Semi-quantitative Semi-quantitative chemical chemical analyses analyses of rubies of rubies and finkpink sapphires from from the the Pamir Pamir Mountain Mountain Range, Range, Republic of of Tajikistan. Tajikistan. Sample weight weight \ wt%Wt% 0.30 ct ct 0.38 ct ct 0.440.44 ct ct0.56 0.56 ct ct0.800.80 ct ct ! OxideOxide 99.3 99.4 99.5 99.6 ! ~0A12°33 99.599.5 99.3 99.4 99.5 99.6 Cr 0 0.224 0.516 0.498 0.286 0.185 Cr2203 0.224 0.516 0.498 0.286 0.185 Ti0 0.156 0.047 0.017 0.091 0.068 Tï02 0.156 0.047 0.017 0.091 0.068 Fe 0 0.018 0.011 0.006 0.007 0.004 Fe2203 0.018 0.011 0.006 0.007 0.004 VVPAs 0.0240.024 0.0150.015 0.0250.025 oms0.025 00.01.0166 Gap3 0.012 0.014 0.013 0.012 0.010 Ga203 0.012 0.014 0.013 0.012 0.010 Figure 8: Idiomorphic negative crystalscrystals knowknownn ttoo gemmologistsgemmologists becausbecausee ofof theirtheir commonly contain immiscible liquid and gasgas spinelspinel deposits.deposits. SinceSince theirtheir initialinitial discoverydiscovery phases. Fibre-optic illumination, 38x. inin ththee earlyearly 1980s,1980s, rubierubiess andand pinpinkk sapphiressapphires havhavee beenbeen recovererecoveredd inin smallsmall quantitiesquantities anandd ThThee infraredinfrared spectraspectra areare dominateddominated byby thethe soldsold inin ththee internationalinternational gemstonegemstone market.market. AlAlaO stretchingstretching frequenciesfrequencies typicaltypical forfor AAss a consequenceconsequence ofof civilcivil war,war, financialfinancial corundum,corundum, betweebetweenn approximatelyapproximately 300300 andand limitationslimitations andand harsharshh climate,climate, onlyonly ththee -1 10001000 cm-cm 1 (peak(peak positionspositions atat approximatelyapproximately richestrichest mine,mine, Snejnaya,Snejnaya, isis currentlycurrently worked.worked. 1 760,760, 642,642, 602602 andand 405405 cm-cm" ; WeferWeferss anandd BellBell,, 108 AlthoughAlthough nono detailsdetails werewere obtainableobtainable asas toto thethe 108 1972).1972). NNoo absorptionabsorption featuresfeatures werweree detecteddetected pastpast oror currentcurrent productionproduction ofof thesthesee deposits,deposits, inin ththee mid-infraredmid-infrared regioregionn (1900(1900 toto itit cancan bebe assumedassumed thatthat anyany productioproductionn iiss -1 40040000 cm-cm 1 ),), relatingrelating ttoo foreignforeign mineralmineral phasesphases smallsmall andand sporadic.sporadic. ItIt followsfollows thatthat ththee oror structuralstructural OHOH groupsgroups (see(see e.g.e.g. VolynetsVolynets potentiapotentiall reservesreserves areare alsoalso unknown.unknown. et al.,ah, 1974;1974; MoonMoon andand Phillips,Phillips, 1994;1994; Smith,Smith, ToTo date,date, finefine gem-qualitygem-quality facetedfaceted 1995;1995; SmithSmith et al.,al, 1997)1997).. gemstonesgemstones areare typicalltypicallyy a caratcarat andand a halfhalf oorr less,less, whilwhilee cabochon-qualitycabochon-quality gemstonesgemstones araree Chemical analysis cutcut inin sizessizes uupp ttoo twtwoo oror threethree carats.carats. LowLow- Semi-quantitativeSemi-quantitative chemicalchemical analysesanalyses ofof thethe qualityquality rubyruby crystalscrystals maymay reachreach sizessizes ooff fivefive specimensspecimens shownshown inin Figure 1 1 revealed revealed the the 5-7 kg.kg. TheThe largeslargestt knownknown gem-qualitygem-quality presencepresence ofof variousvarious minominorr ttoo tractracee elements.elements. facetedfaceted rubrubyy fromfrom PamiPamirr weighsweighs nearlnearlyy 3.53.5 cctt OfOf thesethese,, CrCr isis thethe mostmost significantsignificant minorminor (1.(I. Pojarevski,Pojarevski, 1997,1997, pers.pers. comm.).comm.). ThereThere araree elementelement andand isis responsiblresponsiblee forfor ththee pinkpink toto redred reportsreports thathatt finefine gem-qualitgem-qualityy PamirPamir rubiesrubies oorr huehuess ooff thethe gemstones.gemstones. TITï isis generallygenerally thethe nextnext pinpinkk sapphiressapphires havhavee beenbeen seenseen inin sizessizes upup ttoo mosmostt abundantabundant minorminor toto tractracee element,element, fivefive carats,carats, bubutt thesthesee areare unconfirmed.unconfirmed. followedfollowed byby V,V, FeFe andand Ga.Ga. TheThe contentscontents ooff TheThe PamirPamir rubierubiess andand pinkpink sapphiressapphires araree thesthesee oxidesoxides inin fivefive PamirPamir corundumcorundum samplessamples mostmost similarsimilar toto stonesstones fromfrom ththee QuyQuy ChauChau areare presentedpresented inin Table II. II. In In parts, parts Zr, Z rwas wa salso als o depositsdeposits inin centralcentral Vietnam.Vietnam. However,However, ththee recorderecordedd inin minuteminute quantitiesquantities andand thisthis iiss combinationcombination ofof thethe parallelparallel arrangementsarrangements ooff attributedattributed toto thethe presencpresencee ofof zirconzircon inclusions.inclusions. calcitecalcite inclusions,inclusions, ththee columnarcolumnar concentrationsconcentrations ofof shortshort rutilrutilee needleneedless andand particlesparticles,, andand ththee DiscussionDiscussion negativenegative crystalcrystal inclusions,inclusions, appearappear toto bbee distinctivedistinctive ofof rubiesrubies andand pinkpink sapphiressapphires fromfrom ThThee PamiPamirr mountainsmountains whicwhichh extendextend alongalong thethe Pamirs.Pamirs. TheThe smallsmall mineralmineral oror negativenegative ththee southernsouthern perimeterperimeter ooff TajikistanTajikistan,, inin thethe crystalscrystals accompaniedaccompanied bbyy orientedoriented thithinn filmsfilms formerformer SovietSoviet UnionUnion,, areare probablprobablyy mosmostt wellwell areare alsoalso distinctivedistinctive anandd areare quitequite differentdifferent iinn ]./. Gemm., 1998,26,2,103-109 1998,26,2,103-109 appearanceappearance ttoo thethe doublydoubly truncatedtruncated negativenegative ReferencesReferences crystalscrystals witwithh equatorialequatorial thinthin filmsfilms whichwhich Henn,Henn, U.u.,, andand Bank,Bank, H.,H., 1990.1990. Gem-qualityGem-quality rubiesrubies fromfrom characterizecharacterize ththee rubiesrubies fromfrom magmaticmagmatic ththee PamiPamirr range,range, USSRUSSR.. Bourse Bulletin, 6,6, 19901990,, sources,sources, suchsuch asas inin ThailanThailandd andand Cambodia.Cambodia. Goldshmiede Zeitung. Zeitung. 6, 107-86, 107- 8 InIn contrast,contrast, inclusioninclusion featuresfeatures frequentlyfrequently Henn,U.Henn,U.,, Bank,Bank, H.,H., andand Bank-SchernerBank-Schemer,, M.,M., 19901990.. RubineRubine ausaus demdem Pamir-Gebirge,Pamir-Gebirge, UdSSR. Zeitschrift observedobserved inin rubierubiess fromfrom otheotherr marble-type der Deutschen Gemmologischen Gesellschaft, Gesellschaft, 39(4), 39 (4), sourcessources werewere nonott observedobserved inin thethe rubyruby andand 201-201-44 pinpinkk sapphiresapphire samplessamples fromfrom thethe Pamirs.Pamirs. SuchSuch Hurlbut,Hurlbut, CS.,C.S., andand Kammerling,Kammerling, R.C.R.C,, 1991.1991. Gemology, 2nd 2n d inclusioninclusion featuresfeatures includeinclude swirledswirled growthgrowth eded.. WileyWiley Interscience,Interscience, NewNew YorYorkk HughesHughes,, RW.,R.W., 1996.1996. Ruby andand Sapphire. Sapphire. RWH RW HPublishing, Publishing , structures,structures, colourcolour zoninzoningg andand nest-likenest-like BoulderBoulder,, ColoradoColorado concentrationsconcentrations ofof rutilrutilee needles,needles, typicatypicall ooff KiefertKiefert,, L.,L., andand Schmetzer,Schmetzer, K.K,, 1991.1991. TheThe microscopicmicroscopic rubierubiess fromfrom ththee MogoMogokk stone-tract,stone-tract, oror densedense determinationdetermination ofof structuralstructural propertiepropertiess forfor thethe cross-hatchcross-hatch ttoo flake-likeflake-like inclusioninclusion patternspatterns characterisationcharacterisation ofof opticaloptical uniaxialuniaxial naturalnatural andand andand distinctivedistinctive growthgrowth structuresstructures indicativeindicative syntheticsynthetic gemstones.gemstones. PartPart 1:1: GeneralGeneral considerationsconsiderations andand descriptiodescriptionn ofof ththee methodsmethods.. Journal of of Gemmology, Gemmology, ofof MongMong HsuHsu rubiesrubies,, bothboth fromfrom MyanmarMyanmar 22(6),344-5422(6), 344-54 (Burma),(Burma), variousvarious stringerstringer andand cloud-likecloud-like Koivula,Koivula, J.I.,J.I., andand Kammerling,Kammerling, R.C.RC,, 1989.1989. ExaminatioExaminationn ooff formationsformations commonly seenseen inin thethe rubiesrubies a gemgem spinelspinel crystalcrystal fromfrom thethe PamirPamir Mountains.Mountains. fromfrom northernorthernn VietnamVietnam anandd Nepal,Nepal, andand thethe Zeitschrift derder Deutschen Deutschen Gemmologischen Gemmologischen Gesellschaft, Gesellschaft, mineralmineral inclusioninclusion assemblagesassemblages typicaltypical ofof thethe 3838(2),85-8(2), 85-8 LiddicoatLiddicoat,, RT.,R.T., 1989.1989. Handbook of of gem gem identification, identification, 12th 12t h rubiesrubies fromfrom easteast Africa.Africa. ed.ed. GemologicaGemologicall InstituteInstitute ofof America,America, USUSAA SinceSince gaininggaining itsits independenceindependence fromfrom thethe MoonMoon,, A.R,A.R., andand Phillips,Phillips, M.R,M.R., 1994.1994. DefecDefectt clusteringclustering formerformer SovietSoviet UnioUnionn iinn SeptemberSeptember 19911991,, andand colourcolour inin Fe,Fe, Ti:aAlp3'Ti:αAl2O3. JJ. . Am. Ceram.Ceram. Soc., Soc., 77(2), 77(2) , 356-67356-67 TajikistanTajikistan hahass sufferedsuffered fromfrom regionalregional conflicts,conflicts, Schmetzer,Schmetzer, K,K., 1985.1985. EinEin verbesserteverbesserterr ProbenhalterProbenhalter undund andand thisthis politicalpolitical factor,factor, coupledcoupled withwith ththee diffidiffi seineseine AnwendungAnwendung aufauf ProblemeProbleme derder UnterscheidungUnterscheidung cultyculty ofof physicalphysical accessaccess toto thethe region,region, hashas natiirlichernatürlicher undund synthetischersynthetischer RubineRubine sowiesowie meantmeant thatthat thethe fullfull gemgem potentiapotentiall ofof ththee PamirPamir natiirlichernatürlicher undund synthetischersynthetischer Amethyste.Amethyste. Zeitschrift 109109 regionregion hahass yeyett toto bbee fullyfully exploited.exploited. der DeutschenDeutschen Gemmologischen Gemmologischen Gesellschaft, Gesellschaft, 34(1), 30-4734(1) , 30-47 Schmetzer,Schmetzer, K,K., 1986.1986. AAnn improvedimproved samplesample holderholder andand ititss ususee iinn thethe distinctiondistinction ofof naturalnatural andand syntheticsynthetic rubyruby asas AcknowledgementAcknowledgementss welwelll aass naturalnatural andand syntheticsynthetic amethystamethyst.. Journal ofof Gemmology, 20(1), 20(1) 20-33, 20-3 3 TheThe authorauthor wishewishess toto expressexpress hishis Smith,Smith, CP.,C.P., 1995.1995. A contributioncontribution ttoo understandingunderstanding thethe appreciationappreciation ttoo NicolNicolee Surdez,Surdez, GiibelinGübelin infraredinfrared spectraspectra ofof rubiesrubies fromfrom MongMong HsuHsu,, Myanmar.Myanmar. GemmologicalGemmological Laboratory,Laboratory, Lucerne,Lucerne, Journal of of Gemmology, Gemmology, 25(5), 25 (5)321-35, 321-3 5 Switzerland,Switzerland, andand ProfessorProfessor W.B.W.B. Stem,Stern, Smith,Smith, C.P.CP.,, 1996.1996. IntroductionIntroduction ttoo analyzinanalyzingg internalinternal growth structures: Identification of the negative d InstituteInstitute ofof MineralogMineralogyy andand Petrography,Petrography, growth structures: Identification of the negative d planeplane inin naturanaturall ruby.ruby. Gems & & Gemology, Gemology, 32(3), 32(3) 170-84, 170-8 4 UniversityUniversity ofof BaselBasel,, Switzerland,Switzerland, forfor providingproviding Smith,Smith, CP.,C.P., Giibelin,Gübelin, E.J.,E.J., Bassett,Bassett, A.M.,A.M., anandd Manandhar,Manandhar, semi-quantitativesemi-quantitative chemicalchemical analysis;analysis; DDrr M.N.,M.N., 1997.1997. RubiesRubies andand fancy-colorfancy-color sapphiressapphires fromfrom SuzanneSuzanne Schmidt,Schmidt, InstituteInstitute ofof MineralogyMineralogy andand NepalNepal.. Gems and and Gemology, Gemology, 33(1), 33 (1)24-41, 24-4 1 Petrography,Petrography, UniversityUniversity ofof Basel,Basel, andand DrDr H.-D.H.-D. Volynets,Volynets, EK,F.K., Sidrova,Sidrova, E.A.E.A.,, andand Stsepuro,Stsepuro, N.A.N.A.,, 19741974.. OH-groupOH-groupss inin corundumcorundum crystalcrystalss whicwhichh werewere vovonn Schultz,Schultz, SUVA,SUVA, LucerneLucerne,, Switzerland,Switzerland, forfor growgrownn withwith thethe VerneuiVerneuill technique.technique. Journal ofof performinperformingg scanningscanning electronelectron microscopemicroscope Applied Spectroscopy, 17, 17 1626-28., 1626-28 Translated. Translate dfrom fro m analysis;analysis; alsoalso IvaIvann MM.. Pojarevski,Pojarevski, presidenpresidentt ooff Zhurnal Prikladnoi Prikladnoi Spektroskpii Spektroskpii 1972, 1972 17(6),, 17 1088-91(6), 1088-9 1 BulgariaBulgaria Gems,Gems, Sofia,Sofia, Bulgaria,Bulgaria, forfor providingproviding WebsterWebster,, R.,R., 1994.1994. Gems.Gems. 5th5th ed.ed. EdEd.. ReadRead.. Oxford.Oxford. thethe samplessamples andand usefuluseful information.information. AllAll Butterworth-HeinemannButterworth-Heinemann Wefers,Wefers, K., andand Bell,Bell, G.M.,G.M., 1972.1972. Oxides and and Hydroxides Hydroxides of of photographphotographss areare byby ththee authorauthor unlessunless Aluminium. TechnicalTechnical PaperPaper NoNo.. 19,19, AlcoAlcoaa ResearchResearch otherwiseotherwise noted.noted. LaboratoriesLaboratories,, USUSAA Rubies and and pink pink sapphires sapphires from from the Pamir the Pamir Mountain Mountain Range Rangein Tajikistan, in Tajikistan, former USSR former USSR YouYourr FGAFGA inin NineNine Months! TakTakee ththee courscoursee andand examsexams atat GAGTL'sGAGTL's LondoLondonn GeGemm TutoriaTutoriall CentreCentre TheorTheoryy anandd practicapracticall tuitiotuitionn oonn twtwoo daydayss aa weeweekk frofromm 1lOam0 am ttoo 5 pmpm TheThe nextnext coursecourse startsstarts onon 1414 September ThThee pricpricee ooff £399£39955 includesincludes:: DaytimDaytimee tuitiotuitionn oonn twtwoo fulfulll daydayss aa weeweekk -- basibasicc instrumentinstrumentss -- courscoursee notenotess examinatioexaminationn feefeess -- GAGTGAGTLL membershimembershipp foforr ononee yeayearr FoForr furthefurtherr detaildetailss contaccontactt GAGTGAGTLL EducatioEducationn TelTel:: +4+444 (0(0)) 17 1711 404044 33333344 FaxFax:: +4 +444 (0(0)) 17 1711 404044 88488433 e-mail: [email protected]@btinternet.com InformatioInformationn oonn thisthis anandd otheotherr coursecoursess araree givegivenn oonn ththee GAGTGAGTLL WebsitWebsitee aatt www.gagtlwww.gagtl.ac.uklgagtl. ac.uk/gagtl 110110 SPECIAL OFFER* Special Offer* Usual price* Without rheostat: Single arm FIB0001 (illustrated) £149.25 £199.00 Double arm FIBOO02 £195.00 £260.00 With rheostat: Single arm FIBOO04 £175.12 £233.50 Double arm FIBOO05 £219.37 ·Prices shown exclude VAT, postage and packing Gemstone deposits of the former Soviet Union Ernst M. Spiridonov Geology Department, Moscow State University, Moscow, Russia ABSTRACT: The most important gemstone deposits of the former Soviet Union are described. The deposits range from diamond and ruby to amber and pearl. Some genetic features of gemstones are reported. Keywords: agate, aquamarine, diamond, gemstone, genetic mineralogy, gypsum, ruby, Soviet Union, topaz, tourmaline Introduction 1. Igneous (or magmatogene) associations he famous Russian poet of the XIX century, Feodor Ivanovich Tiutchev Diamond-bearing kimberlite Twrites in one of his poems: The former Soviet Union hosts large 'Nicht, was Ihr meint, ist die Natur in situ diamond deposits with kimberlite 111 Nicht blind und geistlos von Gesicht pipes and accompanying placers accounting Freiheit und Liebe sind in ihr, for one-fifth of world diamond production. Nicht seellos ist sie, fühllos nicht.../ More than 100 kimberlite pipes have been identified from Archaean-Proterozoic 'Nature is neither blind nor spiritless as Siberian and Russian platforms. The age of you implied but includes freedom and love: the Siberian pipes ranges from nor is it without soul or feeling/ [Transl. early Paleozoic to Mesozoic and that of the M.O'D] north Russian pipes from Early Paleozoic to middle Carboniferous. The structure The territory of the former Soviet Union of the kimberlite breccia (autobrecciated occupies one-sixth of the land mass of the foam-lava) pipes does not differ from Earth, including the larger portion of the similar structures in other countries. European and nearly one-half of the Asian The north and centre of the Siberian continents. The geological structure is very platform house the richest pipes, which diverse and for this reason numerous types include the Mir [1], Aikhal [2], Udachnaya of gemstone deposits have been identified: [3] and Internatsionalnaya [4], all in current only the largest and most interesting operation. Mines which may be developed examples are dealt with in this paper. later include Yubileynaya [5], Zarnitsa [6] Generally speaking, gem minerals are late and Batuobinskaya [7]. In the north of the to crystallize from the fluid phase in free Russian platform are the Lomonosovskaya space. The creation of cavities, dissolution, [8], Karpinskaya [9] and Pervomayskaya [10] leaching and sometimes recrystallization pipes (Figure 1). follow original formation. In the paper we Each of these deposits contains millions of shall discuss three types of association, each carats of diamonds and no doubt many will of which hosts gem minerals. be of high gemstone quality. There is a higher © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355-4565 ,i '\ j " • , , text, ii' the in ~ to referred deposit a of that \&J Kf' \ to corresponds 'UAJ\H !iOOkm UHbl:t 250 Number II:JII=-==::I o Union, ~ ~ ~ Soviet Former the of deposits stone jewel and precious the Figure 1: Map of the precious and jewel stone deposits of the Former Soviet Union. Number corresponds to that of a depositof referred to in the text. Map 1: 1-- Figure I ~ >-' >-' >-' N 11 ~ >-' ~ '" !'" ':-< gegemm diamondiamondd percentagpercentagee iinn ththee pipepipess ooff contactcontact.. AAtt ththee MiMirr pipepipe,, foforr exampleexample,, fluid northernorthernn RussiRussiaa thathann iinn thosthosee ooff SiberiaSiberia,, pressurpressuree oonn ththee solisolidd phasephasess iinn ththee kimberlitkimberlitee whicwhichh contaicontainn coarscoarsee anandd mainlmainlyy mediummedium- fluid-saturated foam-lavfoam-lavaa wawass ssoo stronstrongg thathatt to-small-sizeto-small-sizedd crystalscrystals.. ThThee RussiaRussiann kimberkimber- ththee mosmostt durabldurablee individuaindividuall crystalcrystalss havhavee litelitess producproducee mainlmainlyy smalsmalll anandd coarscoarsee beebeenn forciblforciblyy emplaceemplacedd iinn ththee relativelrelativelyy softsoft diamondiamondd crystalscrystals.. SiberiaSiberiann kimberlitekimberlitess havhavee countrcountryy rockrock.. IInn ththee UdachnayUdachnayaa pippipee a produceproducedd manmanyy crystalcrystalss iinn ththee 50-1050-1000 cctt collectiocollectionn ooff diamond-bearindiamond-bearingg edogiticeclogitic weighweightt rangerange.. ThThee largeslargestt RussiaRussiann gemgem- xenolithxenolithss uupp ttoo 1010 ccmm acrosacrosss hahass beenbeen quality diamondiamondd weighweighss 342.342.55 cctt anandd iiss a sampledsampled.. SomSomee ooff ththee xenolithxenolithss contaicontainn a lolott palpalee citrocitronn colourcolour.. ooff diamonddiamondss (u(upp ttoo a thirthirdd iinn volume)volume).. ThThee DiamondDiamondss frofromm kimberlitekimberlitess iinn RussiRussiaa anandd largeslargestt crystalcrystalss rangrangee frofromm 6 toto 1515 mmmm inin sizesize elsewherelsewheree araree equivalenequivalentt iinn sizsizee ttoo (Figure 2). ExaminatioExaminationn ooff thesthesee samplessamples characteristicharacteristicc mantlmantlee megacrystmegacrystss fromfrom certainlcertainlyy supportssupports ththee theortheoryy thathatt diamonddiamond- alkalinalkalinee magmatic rockrockss sucsuchh aass ilmeniteilmenite,, bearinbearingg eclogiteclogitee frofromm ththee mantlmantlee iiss oneone ooff ththee pyropepyrope,, enstatitenstatitee anandd dino-pyroxene.clino-pyroxene. maimainn sourcesourcess ooff diamondiamondd iinn kimberlitekimberlite brecciabreccia.. DiamonDiamondd crystalcrystalss frofromm SiberiSiberiaa araree 9090 peperr cencentt irregulairregularr oorr fragmentarfragmentaryy witwithh onlonlyy 1100 WhilWhilee northernorthernn RussiaRussiann kimberlitekimberlitess araree peperr cencentt showinshowingg regularegularr polyhedrapolyhedrall forms.forms. pyrope-poorpyrope-poor,, SiberiaSiberiann kimberlitekimberlitess areare pyropepyrope- ThThee deepesdeepestt SiberiaSiberiann kimberlitekimberlitess araree pyropepyrope- richrich.. SomSomee SiberiaSiberiann pyroppyropee crystalcrystalss founfoundd iinn poopoorr anandd araree enricheenrichedd iinn diamondiamondd whichwhich associationassociation witwithh chromchromee diopsiddiopsidee showshow anan occuroccurss aass plane-faceplane-facedd octahedraoctahedrall andand alexandritealexandrite effeceffectt witwithh bluish-greebluish-greenn coloucolourr iinn dodecahedradodecahedrall crystalscrystals.. ThThee shallowershallower daylighdaylightt anandd violet-reviolet-redd iinn artificiaartificiall lightlight.. RicRichh SiberianSiberian kimberlitekimberlitess araree richericherr iinn pyroppyropee andand diamondiamondd placerplacerss neanearr ttoo kimberlitkimberlitee pipes araree poorepoorerr iinn diamonddiamond whicwhichh frequentlyfrequently showshow foundfound onon ththee WhitWhitee SeaSea shelf.shelf. curve-facedcurve-faced dodecahedradodecahedra andand otherother 113 antiskeletalantiskeletal forms.forms. Labradorite 113 RussiaRussiann diamondsdiamonds occuroccur inin a widwidee rangerange IridescentIridescent labradoritelabradorite isis foundfound atat thethe veryvery ofof colours,colours, mostmost commonlycommonly colourlesscolourless andand largelarge GolovinskoeGolovinskoe depositdeposit [11][11] locatedlocated inin thethe leslesss commonlycommonly yellowyellow,, green,green, smoky,smoky, brown,brown, YolynVolyn districdistrictt whicwhichh formformss parpartt ooff greygrey andand black.black. CrystalsCrystals withwith densedense colourscolours thethe westernwestern UkrainianUkrainian shield,shield, itselfitself areare comparativelycomparatively rarerare.. Earlier-formedEarlier-formed plane-faceplane-facedd octahedraoctahedra areare mosmostt oftenoften Figure 2: Xenolith of a diamondiferous eclogueeclogite colourlesscolourless whilwhilee later-formedlater-formed crystalscrystals ooff from the Udachnaya kimbkimberliteerlite pipe.pipe. Size of the cuboidcuboid habit,habit, witwithh rounderoundedd edges,edges, havehave a diamond crystal is 6 mm. Photo by yellowisyellowishh colourcolour ofof differentdifferent intensity.intensity. M.A. Bogomolov.limmnm/()7) TheThe interiorinterior featuresfeatures ofof SiberianSiberian diamondsdiamonds includeinclude manymany blob-likeblob-like andand facetedfaceted indusionsinclusions ofof monosulphidemonosulphide solidsolid solutions,solutions, mainlymainly composedcomposed ofof troilitetroilite oror pentlandite,pentlandite, ofof nativenative ironiron andand wiistitewüstite andand intergrowthsintergrowths ofof sulphides,sulphides, wiistitewüstite andand iron:iron: formerlyformerly thesethese werewere believedbelieved toto bebe graphite. ThisThis showsshows thatthat thethe diamondsdiamonds crystallizedcrystallized fromfrom thethe participationparticipation ofof locally-occurringlocally-occurring metalmetal (iron)-oxide-sulphide(iron)-oxide-sulphide melts.melts. KimberliteKimberlite intrusionsintrusions havehave cutcut sedimentarysedimentary sequencessequences andand sillssills ofof dolerites.dolerites. WhenWhen limestonelimestone isis thethe hosthost rockrock itit maymay househouse diamonddiamond crystalscrystals andand pyropepyrope grainsgrains atat distancesdistances ofof upup toto 0.50.5 toto 1 mm fromfrom thethe pipepipe GemstonGemstonee ddepositseposits ooff thethe former SovietSoviet UnionUnion GLOSSARYGLOSSARY OFOF SOMESOME GEOLOGICALGEOLOGICAL TERMTERMSS USEDUSED ININ THISTHIS REVIEREVIEWW AnorthositAnorthositee RockRock composedcomposed mainly ofof plagioclaseplagioclase feldsparfeldspar BoudinBoudin ElongateElongate rounderoundedd fragmentfragment ofof relativelyrelatively strongstrong andand cohesivecohesive rockrock detacheddetached fromfrom a largelargerr piecpiecee byby flowflow ofof ththee moremore plasti plasticc rocksrocks surroundingsurrounding it;it; fromfrom thethe FrenchFrench 'boudin','boudin', a sausagesausage BrecciBrecciaa RockRock composedcomposed ofof angularangular fragmentsfragments mixedmixed withwith finerfiner materialmaterial FaciesFacies GroupGroup tertermm forfor a rangrangee ofof rocksrocks formedformed undeunderr a specifiedspecified rangerange ooff chemical,chemical, pressurepressure,, temperaturetemperature oror otherother physicalphysical conditionsconditions GranitoidGranitoid RockRock withwith graniticgranitic charactercharacter butbut notnot necessarilynecessarily a granitegranite inin thethe strictstrict sensesense HydromicHydromicaa MineralMineral withwith a structurestructure likelike micamica bubutt altered toto accommodateaccommodate moremore OHOH groupsgroups oror watewaterr moleculesmolecules JadeititJadeititee Petrologists'Penologists' tertermm forfor rockrock consistingconsisting largelylargely ofof jadeitjadeitee thethe mineralmineral KarstKarst CountrysideCountryside formedformed onon limestonelimestone whicwhichh hashas sufferedsuffered solutionsolution byby groundwatergroundwater ttoo formform cavescaves andand undergroundunderground drainagedrainage LeucogranitLeucogranitee GraniteGranite consistingconsisting mainlymainly ofof light-colouredlight-coloured mineralsminerals MetaMeta AbbreviationAbbreviation forfor metamorphosedmetamorphosed MetasomatisMetasomatismm ProcessProcess ofof alterationalteration byby actionaction onon rocksrocks ofof fluidsfluids fromfrom anan externalexternal sourcesource Metasomatite Rock formed as a result of metasomatic processes 114 Metasomatite Rock formed as a result of metasomatic processes 114 MiarolitiMiaroliticc AdjectivAdjectivee usedused ttoo describedescribe granitegranite withwith irregularirregular cavitiescavities linedlined withwith wellwell- terminatedterminated crystalscrystals ofof botbothh thethe normalnormal constituentsconstituents ofof ththee rocksrocks (quartz(quartz andand feldspar)feldspar) andand somesome rarerrarer accessoryaccessory mineralsminerals ProtolithProtolith RockRock whichwhich iiss subsequentlysubsequently alteredaltered inin somesome wayway - forfor example,example, byby metameta- morphismorphismm oror metasomatismmetasomatism SeptariaSeptaria Egg-shapedEgg-shaped nodulenoduless upup toto 100100 cmcm acrossacross characterizedcharacterized byby radiatingradiating crackscracks thathatt widenwiden towardtowardss ththee centrecentre andand diedie ououtt nearnear ththee margin,margin, crossedcrossed bbyy crackscracks thatthat araree concentricconcentric withwith thethe marginmargin SupergeneSupergene AdjectivAdjectivee describingdescribing processesprocesses involvinginvolving waterwater percolatinpercolatingg downwardsdownwards fromfrom ththee earth'searth's surface;surface; involvesinvolves solution,solution, reactionreaction andand depositiondeposition ooff mineralsminerals UltrabasitUltrabasitee UltrabasicUltrabasic rock,rock, oneone generallygenerally lowlow inin silicasilica content,content, lowelowerr thanthan basicbasic rocksrocks suchsuch asas mosmostt basaltsbasalts formingforming parpartt ofof a ProterozoicProterozoic anorthositeanorthosite andand Granitic pegmatites gabbro-noritegabbro-norite pluton.pluton. CrystalsCrystals maymay reachreach TheThe deepestdeepest pegmatitepegmatitess areare feldsparfeldspar andand 2200 x 1212 x 3 cmcm andand showshow blackblack withwith darkdark muscovite-rich,muscovite-rich, occurrinoccurringg amongamong highhigh blueblue,, greenish-greenish- oror yellowish-bluyellowish-bluee iridescence.iridescence. pressurepressure metamorphimetamorphicc rocksrocks (kyanite-bearing(kyanite-bearing VerVeryy thithinn ilmeniteilmenite lamellaelamellae areare responsibleresponsible gneisses).gneisses). TheThe northernorthernn KarelianKarelian pegmatitespegmatites forfor thethe blackblack bodybody colourcolour ofof ththee crystals.crystals. TheThe maymay containcontain iridescentiridescent oligoclaseoligoclase andand roserose DzhugdzhurskoDzhugdzhurskoee depositdeposit [12],[12], alsoalso veryvery quartzquartz whilewhile thosethose fromfrom southernsouthern KareliaKarelia may large,large, iiss locatedlocated withinwithin ththee ArcheanArchean containcontain gem-qualitygem-quality almandine.almandine. TranslucentTranslucent anorthositeanorthosite inin thethe easteast ofof thethe AldaAldann shield.shield. oror semi-transparentsemi-transparent peristerite-oligoclaseperisterite-oligoclase JJ.. Gemm., 1998,26,1998,26,2,111-125 2,111-125 withwith anan attractiveattractive lightlight blueblue oror yellowishyellowish lightlight blueblue iridescenceiridescence [known[known inin RussiaRussia asas belomorite]belomorite] iiss founfoundd inin thethe ChupaChupa pegmatitepegmatite [14][14] asas blocksblocks ofof upup toto 2020 x 2020 x 5 cmcm andand alsoalso inin smallsmall segregationssegregations inin thethe contactcontact gneissgneiss.. SomeSome examplesexamples ofof water-transparentwater-transparent oligooligo- claseclase withwith a strong,strong, gentlegentle blubluee schillerschiller areare particularlyparticularly attractive.attractive. Gem-qualityGem-quality amazoniteamazonite hashas beebeenn foundfound inin a shallowershallower graniticgranitic pegmatitepegmatite containingcontaining rarerare metalsmetals atat thethe ZapadnokeivskoeZapadnokeivskoe depositdeposit [151,[15], ththee largestlargest inin thethe formerformer USSR.USSR. ItIt isis situatedsituated onon MounMountt PloskayaPloskaya inin thethe centrecentre ooff thethe KolaKola PeninsulaPeninsula andand consistsconsists ofof a seriesseries ooff thick,thick, steeply-dippingsteeply-dipping pegmatitepegmatite veinsveins witwithh a zonedzoned structure.structure. BrightBright bluish-greenbluish-green amazoniteamazonite occursoccurs inin thethe feldsparfeldspar zonezone ofof thethe Figure 3: VerdeliteVer délite crystals from a graniticgranitic pegmatite: crystals may reach more than 1 pegmatite: crystals may reach more than 1 pegmatite in the Pamirs. Long dimension of the cubiccubic metrmetree inin volumevolume andand showshow bladebladess ooff image is 9 cm. Photo by M.A. Bogomolov. snow-whitesnow-white albitealbite formingforming exexsolutio solutionn patterns.patterns. SuchSuch crystalscrystals areare notnot rare.rare. Beryl - heliodor, aquamarine, morganite.morganite. TheThe shallowestshallowest miaroliticmiarolitic granitegranite MiaroliticMiarolitic pegmatitespegmatites ofof thethe centralcentral UralsUrals andand pegmatitespegmatites ofof thethe Urals,Urals, Ukraine,Ukraine, inin particularparticular thethe MurzinskoeMurzinskoe [18][18],, TransbaikaliaTransbaikalia andand PamirPamir containcontain quartz,quartz, AlabaschkoeAlabaschkoe [19][19] andand AduiskoeAduiskoe depositsdeposits [20[20]] beryl,beryl, topaz,topaz, tourmalinetourmaline andand gem-qualitygem-quality areare celebratedcelebrated forfor theirtheir crystalscrystals ofof heliodorheliodor 115115 crystalscrystals ofof otherother species.species. SmokySmoky quartzquartz whichwhich maymay showshow variousvarious shadesshades ofof greengreen (morion)(morion) crystalscrystals areare widespreadwidespread inin thethe andand yellowyellow andand reachreach 2727 cmcm inin length.length. cavitiecavitiess ooff UkrainiaUkrainiann anandd UralianUralian HeliodorHeliodor ofof gemgem qualityquality isis foundfound inin everyevery pegmatites.pegmatites. TheThe VolynskoeVolynskoe pegmatitepegmatite [16][16] inin tenthtenth cavitycavity ofof ththee YolynVolyn pegmatitepegmatite inin thethe UkrainUkrainee isis a largelarge example,example, relatedrelated ttoo thethe Ukraine andand formsforms crystalscrystals uupp toto 53005300 g.g. apicalapical partpart ofof ththee late-Proterozoiclate-Proterozoic KorostenKorosten AquamarineAquamarine isis fairlyfairly widespreadwidespread inin thethe leucograniteleucogranite pluton:pluton: itit containscontains cavitiescavities uupp toto pegmatitespegmatites ofof ththee centralcentral andand southsouth Urals,Urals, 250250 cubiccubic metresmetres iinn volumevolume andand onon occasionoccasion Altay,Altay, TransbaikaliaTransbaikalia andand Pamir.Pamir. MorganiteMorganite a shaftshaft hashas hadhad toto bebe sunksunk inin orderorder toto reachreach a [vorobyevite][vorobyevite] isis knownknown inin thethe TransbaikaliaTransbaikalia singlesingle crystalcrystal ofof morionmorion.. TheThe authorauthor waswas pegmatitepegmatite (near(near thethe UrchuganUrchugan river,river, closeclose toto presenpresentt atat thethe recoveryrecovery ofof suchsuch a crystalcrystal thethe Russian-MongolianRussian-Mongolian border)border) [21][21] andand atat measuringmeasuring 8 x 1 xx 11 m, m , whichwhich restedrested nearnear- SchaytankaSchaytanka [22][22] inin thethe centralcentral UralsUrals.. horizontallyhorizontally onon thethe drusedruse ofof largelarge orthoclaseorthoclase- Topaz [tyazheloves[tyazheloves (heavyweight)](heavyweight)] isis perthitperthitee coveringcovering thethe cavitycavity walls.walls. SmokySmoky foundfound inin miaroliticmiarolitic pegmatitespegmatites ofof thethe lImenIlmen quartzquartz fromfrom VolyYolynn showsshows colourscolours rangingranging Mountains,Mountains, southsouth UralsUrals [23][23] andand thethe MurzinMurzin- fromfrom a densedense pitch-browpitch-brownn throughthrough brownbrown AduyAduy beltbelt inin thethe centralcentral Urals.Urals. ItIt alsoalso occursoccurs withwith a lilaclilac huhuee ttoo yellow.yellow. inin TransbaikaliaTransbaikalia andand inin ththee easterneastern PamirsPamirs A lightlight andand completelycompletely transparenttransparent violetviolet- wherwheree notable crystalscrystals ofof light-light- andand sky-bluesky-blue roserose amethystamethyst foundfound inin blocksblocks measuringmeasuring upup areare found.found. Blue,Blue, goldengolden andand pale-yellowpale-yellow toto 1.51.5 cubiccubic metremetress occursoccurs withinwithin a pegmatitepegmatite topaztopaz areare foundfound inin thethe pegmatitespegmatites ofof thethe nucleusnucleus inin thethe KenKentt leucograniteleucogranite plutoplutonn [17[17]] middlemiddle Urals.Urals. VeryVery finefine yellowyellow topaztopaz cancan bebe ofof centralcentral Kazakhstan.Kazakhstan. ThisThis areaarea alsoalso containscontains foundfound inin thethe pegmatitespegmatites ofof thethe KukurtKukurt pegmatitepegmatitess inin whichwhich light-bluelight-blue fluoritefluorite ooff deposit,deposit, easterneastern PamirsPamirs [24].[24]. EveryEvery thirdthird opticaloptical andand gemgem qualityquality hahass beebeenn found.found. TheThe cavitycavity ofof thethe VolyYolynn deposidepositt (Ukraine)(Ukraine) crystalscrystals may reacreachh 350350 kgkg inin weight.weight. containscontains gem-qualitygem-quality topaz,topaz, specimensspecimens Gemstone deposits of the formerformer Soviet Union compositioncomposition.. FinFinee rubelliterubellite,, verdeliteverdelite,, indicolitindicolitee anandd polychrompolychromee tourmalinetourmaliness araree distributedistributedd iinn ththee miarolitimiaroliticc pegmatitepegmatitess iinn ththee centrcentree ooff TransbaikaliTransbaikaliaa iinn ththee BorschovochnBorschovochnyy [28[28]] anandd MalkhanskMalkhanskyy [29[29]] ridgesridges.. MosMostt crystalcrystalss araree 2-2-44 ccmm lonlongg thougthoughh somsomee specimenspecimenss araree reportereportedd ttoo havhavee reachereachedd 1122 cmcm.. AAnn unusuaunusuall coloucolourr ooff verdelitverdelitee (elbaite-tsilaisite(elbaite-tsilaisite)) (Figure(Figure 3)3) isis ascribedascribed toto aa Bi-contenBi-contentt ooff 0.0.33 peperr centcent.. AndalusiteAndalusite maymay crystallizecrystallize insteadinstead ofof topaztopaz whewhenn ththee availabilitavailabilityy ooff fluorinfluorinee iiss lowlow.. TransparenTransparentt pinpinkk anandd crimsocrimsonn andalusitandalusitee iinn crystalcrystalss uupp ttoo 1100 xx 0.0.55 x 0.0.55 ccmm i iss recovererecoveredd frofromm ththee YuzhakovskoYuzhakovskoee pegmatitpegmatitee [30[30]] iinn ththee centracentrall UralsUrals.. AndalusitAndalusitee iiss associateassociatedd witwithh Figure 4: Charoitites -- tectonitesteetonites with roundedrounded spessartine-almandinespessartine-almandine,, schorlschorl,, muscovitmuscovitee inclusionsinclusions of greenishgreenish ferrousferrous orthoclase. anandd aquamarineaquamarine.. HambergitHambergitee occuroccurss iinn ththee Long dimensiondimension of imageimage isis 6 cm.em. PhotoPhoto ofof pegmatitepegmatitess ooff ththee PamirsPamirs,, middlmiddlee UralUralss anandd author's samplesample bybyM.A. M.A. Bogomolov.Bogomolov. TransbaikaliaTransbaikalia.. DanburitDanburitee iinn gem-qualitgem-qualityy crystalcrystalss uupp ttoo 1122 x 2 x 2 cmcm cancan bebe foundfound inin weighinweighingg uupp ttoo 111177 kg.kg. TheseThese crystalscrystals areare pegmatitepegmatitess ooff ththee eastereasternn PamirPamirss anandd commonlcommonlyy zonezonedd witwithh ththee centrcentree blubluee anandd TransbaikaliaTransbaikalia.. ththee outsidoutsidee ththee coloucolourr ooff teatea,, ththee sectorsectorss havinhavingg differendifferentt densitiesdensities.. AssociateAssociatedd witwithh SyeniteSyenite pegmatites 116116 ththe.e topatopazz iiss colourlescolourlesss phenakitphenakitee witwithh crystalcrystalss uupp ttoo 4 ccmm longlong.. ThThee VolyYolynn deposidepositt Sunstone asas aa sodicsodic feldsparfeldspar occursoccurs inin thethe alsalsoo containcontainss landscape'landscape'topaz' topaz anandd waterwater- pegmatitepegmatitess ooff ththee IlmeIlmenn anandd VischenevVischenevyy cleaclearr crystalcrystalss measurinmeasuringg uupp ttoo mountainmountainss ooff ththee UralUralss aass welwelll aass iinn manmanyy 2200 x 1100 x 1515 cmcm withwith anan intenseintense brownbrown outerouter otheotherr regionsregions.. IItt containcontainss tintinyy inclusioninclusionss ooff zonzonee 3 ttoo 5 ccmm widwidee anandd a blubluee corecore.. SnowSnow- hematitehematite,, biotitbiotitee anandd otheotherr colourecolouredd mineralmineralss whitwhitee skeletaskeletall cuneatcuneatee fluoritfluoritee crystacrystall aass orienteorientedd lamellalamellaee whicwhichh producproducee aa inclusioninclusionss uupp ttoo 2 ccmm lonlongg appeaappearr ttoo floafloatt iinn characteristicharacteristicc sheesheenn reminiscenreminiscentt ooff ththee susunn aatt ththee blueblue,, ththee effeceffectt suggestinsuggestingg swanswanss iinn flighflightt ititss risinrisingg oorr settingsetting.. againsagainstt aa blubluee skysky.. Sapphire. Dark-bluDark-bluee sapphirsapphiree hahass beebeenn Tourmaline -- rubellite,rubellite, verdelite,verde/ite, indicolite.indieolite. founfoundd iinn somsomee syenitsyenitee pegmatitepegmatitess ooff ththee FinFinee gem-qualitgem-qualityy tourmalintourmalinee occuroccurss iinn ththee centracentrall anandd soutsouthh UralUralss anandd iiss plentifuplentifull iinn miarolitimiaroliticc granitgranitee pegmatitepegmatitess ooff ththee centracentrall somsomee areasareas.. GrainGrainss ooff gem-qualitgem-qualityy sapphirsapphiree UralsUrals,, TransbaikaliTransbaikalia·a anandd ththee PamirsPamirs.. ThThee havhavee occurreoccurredd iinn placerplacerss adjacenadjacentt ttoo ththee best-knowbest-knownn depositdepositss araree SchaytanskoeSchaytanskoe,, syenite-pegmatitesyenite-pegmatite.. SarapulskoSarapulskoee [25[25]] anandd LipovskoLipovskoee [26[26]] iinn ththee centracentrall UralsUrals.. ThesThesee contaicontainn densdensee crimsocrimsonn Nepheline-syeniteNepheline-syenite pegmatites crystalcrystalss ooff elbaite-rubellitelbaite-rubellitee uupp ttoo 1144 ccmm longlong,, Eudialyte,Eudialyte, aa sodiusodiumm calciucalciumm REREEE iroironn knowknownn iinn RussiRussiaa aass siberitsiberitee oorr reredd schorlschorl.. manganesmanganesee zirconiuzirconiumm silicatsilicatee iiss sometimesometimess PolychromPolychromee crystalcrystalss (blac(blackk witwithh crimsocrimsonn used ornamentally. It endsends,, crimsocrimsonn crystalcrystalss witwithh blubluee endsends)) araree used ornamentally. It hahass aa finfinee densdensee lilaclilac- reredd coloucolourr anandd occuroccurss aass separatseparatee alsalsoo commocommonn iinn thesthesee depositsdeposits.. segregationsegregationss ooff uupp ttoo 8 ccmm acrosacrosss iinn alkalinalkalinee MiarolitiMiaroliticc granitegranitess ooff ththee southersouthernn PamirPamirss anandd peralkalinperalkaline e pegmatitpegmatitee anandd coarsecoarse [27[27]] contaicontainn finfinee colourecolouredd tourmalinetourmaliness grainegrainedd nepheline-syenitnepheline-syenitee iinn ththee KhibiniaKhibiniann includinincludingg verdelitverdelitee ooff elbaite-liddicoatiteelbaite-liddicoatite massifmassif,, KolKolaa PeninsulPeninsulaa [31][31].. J].. Gemm.,Gemm., 1998,26,2,111-1251998,26,2,111-125 Post-magmaticPost-magtnatic high-temperature metaso-metaso Post-granitoid metasomatites-Mg skarn matites of alkaline magmatites --fenitesfenites Titanium-clinohumite is isbright brigh torange orang eor o r Charoite rocks areare foundfound inin a uniqueunique reddish-orange.reddish-orange. A varietyvariety enrichedenriched inin TTii mineralizationmineralization ofof ththee SirenevySirenevy KamenKamen depositdeposit occursoccurs iinn thethe zonedzoned bodiebodiess ofof ththee deepestdeepest [32],[32], occurringoccurring inin a halohalo aroundaround magnesiummagnesium skarskarnn inin ththee Kukhi-IalKukhi-lal depositdeposit thethe MurunMurun leucite-kalsiliteleucite-kalsilite plutonpluton inin northnorth [34][34] withinwithin areasareas ofof calciccalcic rocksrocks recrystallizedrecrystallized easterneastern Transbaikalia.Transbaikalia. IInn thithiss contactcontact zone zone,, toto assemblagesassemblages ofof calcite,calcite, spinel,spinel, forsteriteforsterite fluidsfluids replacereplacedd ththee limestonelimestone andand quartzquartz andand otherother silicatessilicates (calciphyres).(calciphyres). TheThe sizesize ooff sandstone.sandstone. CharoiteCharoite isis a layeredlayered silicatesilicate withwith thethe transparenttransparent piecespieces ofof clinohumiteclinohumite rangesranges compositioncomposition (KNa,Sr,B)(CaNa,Mn)z[Si4010](OH,F)(KNaSr/Ba)(CaNaMn)2[Si4O10](OH,F) upup toto 2 cmcm.. Rose-coloured,Rose-coloured, redred andand lilaclilac gemgem- xHX Hz020 andand en masse formsforms thethe spectacularspectacular qualityquality spinelspinel inin thethe Kukhi-IalKukhi-lal depositdeposit isis purplpurplee rocrockk charoititcharoititee withwith palpalee greengreen ferrousferrous associateassociatedd withwith titanium-clinohumittitanium-clinohumitee andand orthoclaseorthoclase andand yelloyelloww tinaksittinaksitee (Figure 4). 4). chloritechlorite withinwithin areasareas ofof recrystallizedrecrystallized Chrome diopside diopside with wit ah finea fin emerald-greene emerald-gree n calciphyre.calciphyre. OctahedralOctahedral andand transparenttransparent butbut colourcolour hahass beenbeen calledcalled SiberianSiberian emerald.emerald. ItIt fracturedfractured spinelspinel crystalscrystals maymay reachreach 7 cmcm inin formsforms separateseparate segregationssegregations upup toto 5050 cmcm inin length,length, butbut thosthosee withwith facetingfaceting potentialpotential areare sizesize andand occursoccurs inin patchespatches inin coarse-grainedcoarse-grained inin thethe rangrangee 5-95-9 mm.mm. orthoclase-phlogopiteorthoclase-phlogopite andand amphiboleamphibole- Lazurite. ThisThis feldspathoidfeldspathoid mineralmineral isis orthoclase-phlogopiteorthoclase-phlogopite metasomatites.metasomatites. TheseThese closeclose toto hauynehauyne iinn compositioncomposition andand occursoccurs inin metasomatitesmetasomatites occuroccur withiwithinn contactcontact zoneszones ooff thethe deepdeep magnesium-enrichedmagnesium-enriched alkalinealkaline skarnskarn alkalinealkaline syenitesyenite andand Cr-bearingCr-bearing ultrabasitultrabasitee ooff whichwhich iiss relatedrelated ttoo thethe horizonshorizons ofof dolomitedolomite thethe InaglinskyInaglinsky massimassiff [33][33] inin thethe westernwestern marblesmarbles andand associatedassociated high-pressurehigh-pressure AldanAldan shield.shield. metamorphicmetamorphic rocksrocks.. TheseThese areare thethe SludyanskoyeSludyanskoye [35][35] andand MalobystrinkskoeMalobystrinkskoe [36][36] depositsdeposits inin thethe southernsouthern BaikalBaikal region.region. Figure 5: Lazurite-ferrous magnesium magnesium skarn skarn at at 117117 the contact betweenbetween calciphyres calciphyres and andhigh high alkali alkali TheTh e LyadzhvardarinskoeLyadzhvardarinskoe depositdeposit [37][37] inin thethe granitoids, Sludyanskoe Sludyanskoe deposit. deposit. Photo Photo by author. by author. PamirsPamir s isis structurallystructurally similarsimilar toto thethe celebratedcelebrated BadakshanskoeBadakshanskoe depositdeposit inin northnorth easteast Afghanistan.Afghanistan. TheThe SludyanskoeSludyanskoe depositdeposit isis composedcomposed ooff patchepatchess andand lenseslenses ofof diopside-Iazurite,diopside-lazurite, calcite-scacalcite-scapolite-lazurite polite-Iazurite,, forsterite-Iazurite,forsterite-lazurite, phlogopite-Iazuritephlogopite-lazurite andand azurite-scapoliteazurite-scapolite rocksrocks occurringoccurring alongalong contactscontacts ofof high-alkalihigh-alkali granitoidgranitoidss anandd graphite-bearingraphite-bearingg marblesmarbles (Figure 5). 5). Lazurite Lazurite crystals crystal sup up to to 5 5 cm cm in in size size areare foundfound inin calciphyres.calciphyres. Lazurite-bearingLazurite-bearing rocksrocks areare considerablyconsiderably impregnatedimpregnated byby pyritepyrite andand ^jTgrainby~grainss ofof nativenative sulphur.sulphur. TheThe compositioncomposition ofof ththee BaikalBaikal lazuritelazurite isis NNa a66Ca2zAl66Si5iPz4[6OM[(SO (504)1.3S50.4s(C03)O.lSClo.1], 4)135S(M5(CO3)0.15Clai]/ andand itsits colourcolour iiss ascribedascribed toto 5.S. Post-granitoid metasomatites-calcic skarns Hedenbergite-wollastonite skarn skarn makes make ans an excellentexcellent ornamentalornamental materialmaterial,, beingbeing composedcomposed ofof micro-,micro-, mezo-mezo- andand macromacro- spherolitesspherolites composedcomposed ofof regularegularr bandbandss ooff differingdiffering thickness.thickness. TheseThese areare radialradial aggregatesaggregates ofof bright-greenbright-green manganousmanganous Gemstone deposits of the former Soviet Union hedenbergitehedenbergite andand light-greylight-grey oror pale-brownpale-brown oligoclaseoligoclase veinsveins andand lenseslenses containingcontaining beryl,beryl, ferrouferrouss andand manganousmanganous wollastonitwollastonitee whichwhich Cr-berylCr-beryl andand emerald.emerald. WhileWhile Cr-berylCr-beryl isis isis predominant.predominant. ThisThis rockrock formsforms a depositdeposit unevenlunevenlyy coloured,coloured, containingcontaining residualresidual approximatelyapproximately 100100 m longlong andand chromechrome spinelspinel andand chrome-magnetite,chrome-magnetite, approximatelyapproximately 1010 m thickthick atat thethe TetiukheTetiukhe emeraldemerald isis colouredcoloured inin crystalcrystal zoneszones andand minminee [38][38] (Dalnegorsk)(Dalnegorsk) neanearr VladivostockVladivostock inin containscontains inclusionsinclusions ofof chromechrome spinelspinel.. LateLate ththee RussianRussian FarFar East.East. metasomaticmetasomatic segregationssegregations containcontain thethe Hessonite-andradite. OneOne ofof ththee largelarge deepest-coloureddeepest-coloured transparenttransparent emeralds.emeralds. TheThe skarn-magnetiteskarn-magnetite depositsdeposits isis atat DaschkesanDaschkesan inin largestlargest emeraldemerald depositsdeposits inin ththee worlworldd areare atat AzerbaidzhaAzerbaidzhann [39].[39]. DistributedDistributed withinwithin thethe MariinskoeMariinskoe [43][43] andand SretenskoeSretenskoe [44][44] inin thethe oreore ofof massivemassive garnet-magnetitegarnet-magnetite areare geodesgéodes centralcentral UralsUrals wherewhere theythey appearappear iinn elongateelongate encrustedencrusted byby acicularacicular epidoteepidote overover whichwhich zoneszones extendingextending forfor approximatelyapproximately 2255 km.km. havehave growngrown largelarge crystalscrystals ofof amethyst,amethyst, Emerald. ItIt isis possiblpossiblee thatthat ththee 'Scythian'Scythian carbonates,carbonates, chalcopyritechalcopyrite andand transparenttransparent emeralds'emeralds' mentionedmentioned byby PlinyPliny ththee EldeElderr areare yellowish-redyellowish-red andand brownish-redbrownish-red andraditeandradite specimensspecimens fromfrom thethe UralsUrals.. TheseThese havhavee a finefine 3+ upup toto 2 cmcm acrossacross.. dense,dense, clearclear greengreen colourcolour witwithh Cr3+ aass thethe mainmain chromophore.chromophore. Gem-qualityGem-quality crystalscrystals Post-granitoid metasomatites - zwitter and varyvary a goodgood dealdeal inin size:size: productionproduction iinn 19771977 greisen reachedreached 1212 600600 ctct (1979(1979 7 000000 ct,ct, 19821982 TheThe high-temperaturehigh-temperature acidicacidic (HF)(HF) 1290012 900 ct,ct, 19901990 1045010 450 ct).ct). InIn totaltotal,, ththee minesmines metasomatitemetasomatitess areare zwitter (zinnwaldite(zinnwaldite andand havhavee producedproduced moremore thanthan 2.52.5 milliomillionn caratscarats Li-CLi-Css phlogopite-bearing)phlogopite-bearing) andand greisengreisen ofof facetedfaceted stonesstones andand approximatelyapproximately 5050 tonstons (muscovite-bearing).(muscovite-bearing). TheyThey may sometimessometimes ofof Cr-bearingCr-bearing beryl.beryl. ReservesReserves areare estimatedestimated bebe accompaniedaccompanied bbyy quartzquartz veins andand lenseslenses atat approximatelyapproximately 1010 millionmillion carats.carats. 118118 withwith finefine crystalscrystals ofof aquamarine,aquamarine, topaztopaz andand Phenakite occursoccurs withwith ththee emeraldemerald inin morionmorion,, amongamong others.others. glimmerite,glimmerite, oligoclaseoligoclase veinsveins anandd cavitiescavities InIn RussiaRussia aquamarines do d onot no toriginate originat e amongamong them,them, withwith crystalscrystals reachinreachingg 2200 cmcm inin fromfrom pegmatitespegmatites bubutt frofromm zwitter.zwitter. DenselyDensely- size.size. IntergrowthsIntergrowths ofof phenakitphenakitee weigweighh uupp toto colouredcoloured longlong prismatiprismaticc crystalscrystals upup toto 3030 ccmm 6.56.5 kg.kg. TransparentTransparent crystalscrystals araree colourless,colourless, areare foundfound atat thethe SherlovayaSherlovaya GoraGora depositdeposit [40[40]] moremore rarelyrarely pinkpink oror wine-yellow.wine-yellow. A waterwater- inin Transbaikalia.Transbaikalia. TheThe colourcolour isis duedue toto clearclear andand darkdark smokysmoky phenakitephenakite crystalcrystal divalentdivalent FeFe impuritiesimpurities whichwhich areare stablestable inin anan measuringmeasuring 1313 x 1212 x 7 cmcm waswas founfoundd iinn 19911991 acidicacidic environment.environment. FineFine greenish-bluegreenish-blue atat thethe MariinskoeMariinskoe deposit.deposit. aquamarinesaquamarines areare foundfound inin thethe Alexandrite, thethe chrysoberylchrysoberyl varietyvariety AdunchilonskoeAdunchilonskoe depositdeposit [41][41] inin showingshowing anan emerald-greenemerald-green coloucolourr inin daylightdaylight TransbaikaliaTransbaikalia andand inin ththee quartz-pyritequartz-pyrite- andand reddish-violetreddish-violet inin artificialartificial lightlight,, waswas wolframitewolframite veins ofof thethe AkchatauAkchatau depositsdeposits discovereddiscovered atat thethe emeraldemerald minesmines iinn ththee UralsUrals [42][42] inin centralcentral Kazakhastan.Kazakhastan. ShortShort prismaticprismatic andand namednamed forfor thethe famousfamous TsarTsar AlexandeAlexanderr IIII crystalscrystals ofof blubluee topatopazz andand largelarge smokysmoky onon thethe dayday ofof attainingattaining hishis majoritymajority.. TheThe quartzquartz crystalscrystals withwith deepdeep colourcolour areare oftenoften changechange ofof colourcolour isis consideredconsidered ttoo havhavee a associatedassociated withwith aquamarine.aquamarine. mystimysticc associationassociation withwith thethe TsarTsar iinn thathatt thethe ProcessesProcesses ofof hydrofluorihydrofluoricc metasomatismmetasomatism greengreen reflectsreflects hishis humanityhumanity anandd concernconcern forfor oftenoften occuroccur outsideoutside thethe parentparent leucograniteleucogranite thethe RussianRussian peasantrpeasantryy whilewhile thethe reredd callcallss toto pluton.pluton. WhenWhen ultrabasiteultrabasite materialmaterial containingcontaining mindmind hishis assassination.assassination. RussianRussian alexandritealexandrite chrome-magnetitechrome-magnetite (e.g.(e.g. serpentinite,serpentinite, talctalc- hahass beenbeen consideredconsidered thethe bestbest inin ththee worldworld carbonatecarbonate rock)rock) wawass infiltrated,infiltrated, zwitterzwitter- andand commonlycommonly formsforms penetratiopenetrationn trillingtrillingss ooff glimmeriteglimmerite containingcontaining Li-CsLi-Cs phlogopite,phlogopite, rhombo-pyramidarhombo-pyramidall andand shorshortt prismaticprismatic fluorite,fluorite, fluorapatite,fluorapatite, emerald,emerald, chrysoberyl,chrysoberyl, formsforms oror aggregatesaggregates ofof trillings.trillings. ThThee largeslargestt ooff phenakitephenakite andand BeBe margaritmargaritee werewere formed.formed. thesthesee measuresmeasures 2525 x 1414 x 1111 cmcm.. AlexandriteAlexandrite TheThe metasomatitemetasomatite isis accompaniedaccompanied byby mineralizatiomineralizationn isis closelyclosely relatedrelated ttoo thathatt ooff J.J. Gemm., 1998, 26, 2,2,111-125 111-125 emeraldemerald bubutt ththee depositsdeposits areare separate,separate, thethe alexandritealexandrite beinbeingg foundfound inin glimmeriteglimmerite andand margarite-plagioclasemargarite-plagioclase veinsveins inin associationassociation withwith pinpinkk fluorite.fluorite. Quartz, pink topaz and euc/ase.euclase. LateLate mineralsminerals ofof thethe zwitter-greisezwitter-greisenn assemblagesassemblages areare generatedgenerated byby slightlyslightly acidicacidic toto neutralneutral 3+ fluids,fluids, depleteddepleted inin fluorine,fluorine, iinn whichwhich Fe3+ iiss stable.stable. TheThe resultsresults areare veinsveins withwith quartz,quartz, pinkpink topaztopaz andand euclaseeuclase iinn ththee KochkarKochkar district,district, southernsouthern Urals.Urals. CrystalsCrystals ofof pinkpink fluor-hydroxylfluor-hydroxyl topatopazz mamayy reachreach 5 emcm inin lengthlength andand multi-colouredmulti-coloured euclaseeuclase 8 em;cm; mostmost areare foundfound inin placersplacers.. Post-granodiorite metasomatites - beresiteberesite Rock crystal andand light-colouredlight-coloured smokysmoky Figure 6: Brocaded jasper-like moss agates quartzquartz areare foundfound inin mid-temperaturemid-temperature with goethite and hematite, western Georgia. Long dimension of image is 13 cm. Photo by hydrothermalhydrothermal ankerite-quartz-sericiteankerite-quartz-sericite M.A. Bogomolov of author's sample. metasomatitesmetasomatites (beresite)(beresite) atat ththee BeriozovskoeBeriozovskoe depositdeposit [46][46] inin thethe UralsUrals.. alongalong thethe edgesedges ofof foldedfolded areasareas andand inin thethe lowerlower partsparts ofof plateplate marginsmargins.. MineralMineral Post-granitoid metasomatites - argillizites Post-granitoid metasomatites - argillizites assemblagesassemblages ofof thethe zeolitezeolite faciesfacies inin Amethyst. ZoneZoness ofof low-temperaturelow-temperature metavolcanimetavolcanicc rocksrocks areare heulandite,heulandite, stilbitestilbite,, hydrothermalhydrothermal hydromicaceoushydromicaceous andand quartzquartz- chabazite,chabazite, chlorite,chlorite, albite,albite, quartz,quartz, 119119 chlorite-kaolinitechlorite-kaolinite metasomatitesmetasomatites (argillizites)(argillizites) chalcedony,chalcedony, amethyst,amethyst, celadonite,celadonite, hostedhosted inin granite,granite, syenitesyenite andand monzonitemonzonite montmorillonite,montmorillonite, goethitegoethite andand pyrite.pyrite. often contain quartz veins with amethyst often contain quartz veins with amethyst Agate isis widespreadwidespread amongamong metavolcanicmetavolcanic druses. They occur in the central Urals, druses. They occur in the central Urals, rocksrocks iinn ththee north-eastnorth-east ofof EuropeaEuropeann Russia,Russia, particularly at the Vatikha deposit [47] where particularly at the Vatikha deposit [47] where ththee mountainsmountains ofof thethe Crimea,Crimea, Caucasus,Caucasus, a celebrated dark blood-red colour of a celebrated dark blood-red colour of southernsouthern Urals,Urals, centralcentral andand easterneastern amethyst is found together with lighter- amethyst is found together with lighter Kazakhstan, easterneastern Siberia,Siberia, ChukotkaChukotka andand coloured sceptre forms, at Aduy [48] and at coloured sceptre forms, at Aduy [48] and at easterneastern TransbaikaliaTransbaikalia southsouth ofof thethe RussianRussian Vischnevskoe [49] in Kazakhstan. Vischnevskoe [49] in Kazakhstan. FaFarr East.East. TheThe bestbest agatesagates occuroccur inin JurassicJurassic metavolcanicmetavolcanic rockrockss inin GeorgiaGeorgia [50][50] andand 2.2. MetamorphicMetamorphic associationsassociations resemblresemblee brocadebrocadedd jaspejasperr inin theitheirr patterningpatterning (Figure 6). 6). Fine Fin eagates agate sare are found found in in mesozoic mesozoic- Low-grade zeolite fadesfacies metamorphic rocksrocks paleogenpaleogenee metavolcanicmetavolcanic rockrockss iinn ArmeniArmeniaa atat MostMost ofof ththee agateagate depositsdeposits occuroccur inin ththee IdzhevaIdzhevann [51][51] andand SarigiukhSarigiukh [52[52]] volcanicvolcanic rockrockss ofof a widewide rangerange ooff deposits.deposits. TheThe formerformer depositdeposit containcontainss agateagate compositions.compositions. MostMost areare basaltbasaltss inin whicwhichh gasgas witwithh amethystamethyst andand goethitgoethitee coatedcoated withwith bubblebubbless havhavee beebeenn filledfilled bbyy agateagate reddisreddishh heulanditeheulandite (Figure 7); ththee latterlatter (metamorphosed(metamorphosed amygdaloidalamygdaloidal basalts)basalts).. NoNo deposidepositt containscontains mossmossyy celadoniteceladonite andand agateagate occurs,occurs, howeverhowever,, inin thethe goethite-bearinggoethite-bearing agateagate (Figure 8). AgateAgate contemporaneouscontemporaneous volcanicvolcanic rocks.rocks. TheyThey occuroccur mineralizationmineralization inin SiberiaSiberia iiss oftenoften onlyonly inin ththee volcanivolcanicc sequencessequences affectedaffected byby accompaniedaccompanied byby finefine zeolitzeolitee drusedrusess withwith metamorphismmetamorphism duringduring buriaburiall - inin otherother crystalscrystals ofof gem-qualitygem-quality prehniteprehnite andand wordswords low-gradelow-grade zeolitezeolite faciesfacies apophyllite.apophyllite. OnOn passinpassingg ttoo thethe laumontitelaumontite- metamorphismmetamorphism (T(T = 130-220°C,130-220°C, P = 1-51-5 kb)kb).. prehniteprehnite faciesfacies (220-300°C)(220-300°C) agatesagates areare SuchSuch metamorphosemetamorphosedd rocksrocks araree widespreadwidespread recrystallizedrecrystallized andand loselose theitheirr softsoft lustre.lustre. Gemstone deposits of the formerformer Soviet Union FigureFigure 7: 7: Agates Agates with with amethyst amethyst and and goethite, goethite, FigureFigure 8:8: CarpetCarpet agatesagates withwith goethitegoethite and withwith red red rim rim of of heulandite heulandite hosted hosted in metavolcanic in metavolcanic celadonite,celadonite, Sarygiukh. Sarygiukh. Long Long dimension dimension of images of images rocks,rocks, Idzhevan. Idzhevan. Long Long dimension dimension of image of image is 18 cm. is 18 cm.isis 1919 cm. cm. Photo Photo by by M.A. M.A. Bogomolov Bogomolov of author'sof author's PhotoPhoto by by M.A. M.A. Bogomolov Bogomolov of author's of author's sample. sample. sample.sample. JetJet alsoalso occursoccurs inin lignitelignite andand softsoft coalcoal faciesfacies (T(T = =approximately approximately 300°e,300°C , PP == 2-6 2-6 kb)kb) depositsdeposits in in low-grade low-grade zeolitezeolite metasedimentary metasedimentary isis jasperjasper (Figure(Figure 9). 9). This Thi sis i sthe th efine-grained fine-graine d bodies.bodies . OccurrencesOccurrences areare atat BeschuevskoeBeschuevskoe [53][53] metametaroc rockk withwith predominantlypredominantly quartzquartz inin thethe Crimea,Crimea , TkvartchelyTkvartchely [54],[54] , TkibuliTkibuli [55][55] composition.composition. ItIt isis colouredcoloured byby hematite,hematite, andand AkhaltsikheAkhaltsikhe [56][56 ] inin westernwestern GeorgiaGeorgia andand garnet,garnet, epidote,epidote, pumpellyite,pumpellyite, actinolite,actinolite, CheremkhovskoeCheremkhovskoe nearnear BaikalBaikal [57].[57]. chloritechlorite oror manganesemanganese minerals.minerals . TheThe manymany 120120 depositsdeposits ofof differentdifferent kindskinds ofof jasperjasper Prehnite-pumpellyitePrehnite-pumpellyite facies fades metamorphic metamorphic rocks rocks (cherty-metasedimentary,(cherty-metasedimentary, chertycherty debris,debris, IfIf agateagate isis characteristiccharacteristic forfor zeolitezeolite carbonaceous-cherty,carbonaceous-cherty, volcanic-chertyvolcanic-cherty rocks)rocks) facies,facies, thethe correspondingcorresponding materialmaterial forfor andand felsicfelsic volcanicvolcanic rocksrocks lie lie inin thethe greenstonegreenstone higher-temperaturehigher-temperature prehnite-pumpellyiteprehnite-pumpellyite beltsbelts fromfrom thethe southsouth UralsUrals (Orsk(Orsk [57], KalkanskKalkansk [58],[58] , MuldakaevskoeMuldakaevskoe [59][59 ] andand others)others) toto thethe near-Polarnear-Polar regionregion atat thethe AltaisAltais Figure 9: Map of France composed of the Figure 9: Map of France composed of the (Kolyvan(Kolyvan [60][60 ] andand others).others) . TheyThey areare alsoalso differentdifferent kinds kinds of of Ural Ural jaspers. jaspers. Product Product of theof the found in central Asia and Kazakhstan. EkaterinburgEkaterinburg faceting faceting factory. factory. Late Late XIX XIXcentury. century. foun d in central Asia and Kazakhstan. PhotoPhoto by by author. author. Prehnite-pumpellyitePrehnite-pumpellyite faciesfacies meta-meta- morphismmorphism isis fluid-dominated, fluid-dominated, thethe mainmain fluidfluid beingbeing waterwater vapour.vapour. MetarocksMetarocks containcontain numerousnumerous fracturesfractures resultingresulting fromfrom hydrofracturing.hydrofracturing. TheseThese fracturesfractures areare filledfilled byby thethe constituentconstituent mineralsminerals ofof metarocksmetarocks -- quartz,quartz, prehnite,prehnite, epidote,epidote, albite,albite , chloritechlorite andand carbonates.carbonates. MetamorphismMetamorphism affectedaffected notnot onlyonly sedimentarysedimentary andand volcanicvolcanic sequencessequences butbut alsoalso magmaticmagmatic massifs.massifs. Prehnite-pumpellyitePrehnite-pumpellyite faciesfacies metagabbroidsmetagabbroids andand meta-ultrabasicmeta-ultrabasic rocksrocks contain contain aa range range ofof gemgem andand ornamentalornamental minerals.minerals . TheyThey areare relatedrelated mainlymainly toto thethe rodingiterodingite associationassociation comprisingcomprising grossular,grossular, andraditeandradite (including(including demantoid),demantoid), vesuvianite,vesuvianite, uvarovite,uvarovite ,chrome chrome titanite titanite and and jadejade as as precious precious rodingite.rodingite . J./ . Gemm.,Gemm., 1998,1998,26,2,111-125 26, 2,111-125 Grossular AA recordedrecorded grossulargrossular depositdeposi t withwith greenishgreenish andand yellowish-greenyellowish-green crystalscrystals upup toto 8 emcm inin sizesize lieslies inin thethe ViluyViluy riverriver valleyvalley [61][61] ofof ththee easterneastern SiberianSiberian platform.platform. GrossularGrossular andand vesuvianitevesuvianite crystalscrystals areare includedincluded inin a fine-grainedfine-grained groundmassgroundmass ooff hydrogrossularhydrogrossular composition.composition. Demantoid is i sandradite andradite or o rhydroandradite hydroandradite containingcontaining chromiumchromium andand isis associatedassociated withwith serpentine,serpentine, asbestos,asbestos, magnetitemagnetite andand residualresidual chromechrome spinellids.spinellids. ItIt containscontains finefine syngeneticsyngenetic actinoliteactinolite fibresfibres whichwhich givegive a goldengolden tingetinge toto thethe stones.stones. PavePavell PiotrovichPiotrovich Bazhov,Bazhov, a writerwriter fromfrom ththee Urals,Urals, saidsaid thatthat demantoiddemantoid 'smells'smells asas sweetsweet asas SpringSpring andand sun'.sun'. HeavilyHeavily serpentinizedserpentinized ultrabasitesultrabasites iinn thethe centralcentral UralUralss hosthost a numbenumberr ofof deposits,deposits, includingincluding Figure 10: Druse of emerald-green uvarovite uvarovite crystals and acicular shuiskite (on(on PoldnevskoePoldnevskoe [62][62] andand BobrovskoeBobrovskoe [63].[63]. TheThe metachromitite), Saranovskoe deposit. LongLong finestfinest specimensspecimens areare foundfound inin placersplacers andand dimension of image is 3 cm. Photo by oneone high-qualithigh-qualityy exampleexample weighingweighing 7676 ctct M.A. Bogomolov of of author's author's sample. sample. appearsappears ttoo bbee unique.unique. ChromeChrome garnetsgarnets ofof thethe rodingiterodingite Metamorphic rocks of medium temperature association,association, uvarovituvarovitee andand chrome-grossularchrome-grossular and pressure fromfrom ththee SaranovskoeSaranovskoe depositdeposit [64][64] inin thethe north-westnorth-west ofof ththee centralcentral UralsUrals havhavee a finefine 'Grlets','Orlets', aa rhodoniterhodonite rock rock of overyf ver finey fin pinke pin k 121121 colour.colour. ThisThis depositdeposit isis a steeplysteeply dippingdipping andand crimsoncrimson colour,colour, isis a celebratedcelebrated RussianRussian peridotiteperidotite massimassiff containingcontaining numerousnumerous ornamentalornamental material.material. ItIt isis a manganousmanganous chromititechromitite bedbedss andand thethe massifmassif itselfitself isis crosscross cherty-carbonaceouscherty-carbonaceous metamorphicmetamorphic rockrock inin cutcut bbyy a seriesseries ofof gabbro-doleritegabbro-dolerite dykes.dykes. ThThee thethe greenschistgreenschist facies.facies. TheThe finestfinest materialmaterial massifmassif wawass subsequentlysubsequently tectonizedtectonized andand comescomes fromfrom thethe Malo-SidelnikovskoeMalo-Sidelnikovskoe depositdeposit affectedaffected byby regionaregionall prehnite-pumpellyiteprehnite-pumpellyite [65]:[65]: otherother depositsdeposits areare locatedlocated notnot farfar fromfrom faciesfacies metamorphismmetamorphism.. FracturesFractures causedcaused byby Ekaterinburg.Ekaterinburg. 'OrIets''Orlets' isis composedcomposed ofof finefine hydrofracturinhydrofracturingg iinn chrometitechrometite areare filledfilled bbyy micrograinedmicrograined aggregateaggregatess ofof rhodonite,rhodonite, carbonates,carbonates, uvarovite,uvarovite, chrome-chlorite,chrome-chlorite, quartzquartz rhodochrosite,rhodochrosite, tephroitetephroite (a(a MnMn silicatesilicate ofof thethe andand pumpellyitpumpellyitee witwithh chromechrome titanitetitanite,, rutilerutile,, olivineolivine group),group), sonolitesonolite (a(a hydratedhydrated MnMn diaspore,diaspore, anataseanatase andand millerite.millerite. TheThe fracturefracture silicatesilicate ofof thethe humitehumite group),group), spessartinespessartine andand surfacesurface inin chromititechromitite isis oftenoften encrustedencrusted withwith quartzquartz withwith supergenesupergene blackblack MnMn oxidesoxides drusesdruses ofof uvaroviteuvarovite crystalscrystals upup toto 6 mmmm inin size.size. locatedlocated alongalong fracturesfractures.. CobaltianCobaltian rhodoniterhodonite UvarovitUvarovitee andand chromechrome grossulargrossular areare oftenoften withwith anan unusuaunusuall lilac-violetlilac-violet colourcolour hashas associatedassociated witwithh chrome-chloritechrome-chlorite andand acicularacicular recentlyrecently beenbeen discovereddiscovered inin thethe PolarPolar Urals.Urals. shuiskiteshuiskite (Figure 10), 10), a abrown brown mineral minera lof o fthe th e Rock crystal, crystal, amethyst amethyst and an citrined citrine as wellas wel asl as pumpellyitepumpellyite groupgroup containingcontaining chromium.chromium. axinite andand titanitetitanite as a ssplendid splendid crystals crystal soccur occu r inin thethe AlpineAlpine veins hostedhosted inin meta-morphicmeta-morphic Chrome titanite fromfrom thethe SaranovskoeSaranovskoe rocksrocks ofof thethe Near-PolarNear-Polar UralsUrals (the(the depositdeposit isis a finefine emerald-greenemerald-green toto goldengolden- KhasavarkaKhasavarka depositdeposit - No.No. 6666 andand others).others). greengreen andand occursoccurs asas transparenttransparent crystalscrystals upup toto 2020 x 2020 x 5 mmmm iinn sizesize thoughthough mosmostt areare lessless thanthan 5 mm.mm. FacetedFaceted chromechrome sphenesphene isis similarsimilar Metamorphic rocks of high pressure inin colourcolour ttoo ththee finestfinest demantoid.demantoid. Ruby occursoccurs onlyonly inin thethe high-pressurehigh-pressure metamorphicmetamorphic complexecomplexess withinwithin corecore partpartss ooff thethe PamirsPamirs andand UraliaUraliann foldedfolded areas,areas, amongamong Gemstone depositsdeposits ofof thethe formerformer SovietSoviet UnionUnion Figure 11: Table set with Urals malachite.malachite. Russian mosaic style typical of XIX centurycentury production. Ekaterinburg Museum of Applied Art. Photo by author. meta-evaporitesmeta-evaporites (most(most oftenoften a dolomitedolomite marble).marble). A ruby-bearingruby-bearing beltbelt inin thethe easterneastern PamirsPamirs isis 200200 kmkm longlong andand isis thethe mostmost interestinginteresting asas a rubrubyy producerproducer.. DepositsDeposits occuroccur atat SnezhnoeSnezhnoe [67],[67], NadezhdNadezhdaa [68][68] andand Tura-KulomaTura-Kuloma [69].[69]. TheThe semi-transparentsemi-transparent prismatiprismaticc rubyruby crystalscrystals reachreach 23002300 g andand Figure 12: The figure of the legendary 'Hostess 122 122 2255 cmcm inin length.length. TransparentTransparent deep-coloureddeep-coloured of Copper (malachite) Mountain' produced from gypsum-selenite, 1975. Height of the figure is areasareas areare founfoundd inin ththee apexapex andand inin thethe 130 cm. Ekaterinburg Museum of Applied Art.Art. peripheral parts of the crystals and fine peripheral parts of the crystals and fine Photo by author. facetefacetedd stonesstones upup ttoo 2 ctct havehave beenbeen obtained.obtained. RubRubyy mineralizationmineralization occursoccurs withinwithin a sequencesequence ofof coarse-grainedcoarse-grained dolomite,dolomite, calcitecalcite corundumcorundum formation.formation. SuchSuch conditionconditionss areare andand magnesitmagnesitee marblemarbless containiI1gcontaining memett inin bothboth meta-evaporitesmeta-evaporites anandd metameta- intercalationsintercalations ofof crystallinecrystalline schistschist withwith ultrabasitesultrabasites.. scapolitescapolite.. RubyRuby crystalscrystals occuroccur inin patchespatches Scapolite. Gem-qualityGem-quality scapolitescapolite inin yellow,yellow, withwith carbonates,carbonates, scapolitescapolite andand fuchsite.fuchsite. AtAt light-lilaclight-lilac toto lilaclilac andand deep-purpledeep-purple colourscolours isis ththee Makar-RuzMakar-Ruz depositdeposit [70][70] inin thethe PolarPolar UralsUrals widespreawidespreadd inin cavitiescavities amongamong scapolitscapolitee andand rubierubiess occuroccur withiwithinn smallsmall bodiesbodies ooff albite-scapolitealbite-scapolite veinsveins hostedhosted iinn metameta- phlogopitephlogopite plagioclasiteplagiodasitess hostedhosted inin metameta- evaporiteevaporite sequencessequences ofof thethe easterneastern PamirsPamirs ultrabasitesultrabasites.. neanearr thethe towntown ofof Murgab.Murgab. TheThe largeslargestt depositdeposit isis thethe KukurtKukurt [71][71] wherewhere scapolite-bearingscapolite-bearing ExperimentsExperiments indicateindicate thathatt atat a highhigh COC02 fugacityfugacity spinelspinel breaksbreaks downdown accordingaccording toto stockworksstockworks areare found.found. Gem-qualityGem-quality scapolitescapolite crystalscrystals weighweigh upup toto 150150 g anandd somsomee displaydisplay ththee reactionreaction MgAlz04MgAl204 + COC02z --i>-* Alz20O3s asterism.asterism. SomeSome placesplaces produceproducedd crystalcrystalss ooff + MgC0MgCO3s.. TheThe experimentsexperiments showshow thatthat atat temperaturestemperatures aboveabove 400°400°CC aluminiumaluminium gem-qualitygem-quality weighingweighing uupp ttoo 2200 kg.kg. oxideoxide migratesmigrates withinwithin aqueousaqueous fluidfluid - inin CompositionallyCompositionally itit isis marialitemarialite containingcontaining otherother words,words, corundumcorundum formationformation isis appreciableappreciable C~-CO^" andand S~S-.. possiblpossiblee inin thethe metamorphimetamorphicc processprocess Cordierite withwith deep-bluedeep-blue anandd blue-violetblue-violet providedprovided thatthat ththee environmentenvironment isis fluidfluid- colourscolours formsforms patchepatchess andand metacrystmetacrystss withinwithin saturated.saturated. LowLow activitiesactivities ofof silica,silica, metarockmetarockss ofof thethe MountainMountain AltaysAltaysmm [72][72],, potassiupotassiumm andand sodium,sodium, andand ththee presencepresence ofof EasEastt PamirsPamirs andand Transbaikalia.Transbaikalia. TransparentTransparent chromium,chromium, areare necessarnecessaryy forfor rubyruby piecepiecess maymay reacreachh 44x3x x 3 x 33 cmcm iinn size.size. J./. Gemm., 1998, 26,26,2,111-125 2, 111-125 Lazulite,Lazulite, a Mg-Al-FeMg-AI-Fe2+2+-Fe-Fe33++ phosphatephosphate,, iiss fairlfairlyy widespreawidespreadd iinn metarockmetarockss o off elevatedelevated pressure.. ThThee onlonlyy RussiaRussiann deposidepositt ooff gemgem- qualitqualityy lazulitlazulitee iiss locatelocatedd neanearr thethe LongotiegaLongotiegann riveriverr iinn ththee PolaPolarr UralUralss [73][73].. TheThe lazulitlazulitee patchepatchess iinn cavitiecavitiess iinn quartquartzz veinsveins measurmeasuree uupp ttoo 3300 x 2200 cmcm.. TransparenTransparentt finefine blubluee anandd dark-bludark-bluee crystalcrystalss araree founfoundd uupp ttoo 2-2-44 mmmm,, sometimesometimess reachinreachingg 3300 mmmm.. FinFinee cabochoncabochonss araree fashionefashionedd frofromm thithiss hematitehematite- includeincludedd material.material. Nephrite, green and white. WhitWhitee nephritnephritee iiss a fine-grainefine-grainedd tremolittremolitee witwithh feltedfelted texturetexture resultinresultingg frofromm crystallizatiocrystallizationn undeunderr highhigh- pressurpressuree conditionsconditions,, anandd witwithh greengreen nephritenephrite,, formformss alonalongg ththee contactcontactss betweenbetween chromite-bearinchromite-bearingg serpentinizeserpentinizedd ultrabasitesultrabasites anandd gabbroidgabbroidss iinn mosmostt depositsdeposits.. VariatioVariationn ooff Figure 13: Agates (carnelian and quartzite)quartzite) coloucolourr iiss duduee ttoo differencedifferencess iinn ththee amountamountss ooff hosted in silicified limestone,Limestone, Golutvin. Long Cr343+,, Fe2+ anandd Fe3+ iinn ththee tremolitetremolite.. DepositsDeposits dimension of image is 9 cmcm.. Photo of author's ooff greegreenn nephritnephritee areare aatt OspinskoOspinskoee [74][74],, sample by M.A. Bogomolov.Bogomolov. BartogolskoBartogolskoee [75] anandd aatt otheotherr placeplacess iinn thethe eastereasternn Sayans.Say ans. DepositDepositss alsalsoo occuoccurr iinn thethe a plagiogranitoidplagiogranitoid oror leucogabbroleucogabbro containingcontaining westerwesternn SayansSayans atat KartashubinskoeKartashubinskoe [76][76],, chromite:chromite: atat low-gradlow-gradee metamorphismmetamorphism suchsuch PolarPolar UralUralss andand Transbaikalia. rocksrocks areare alteredaltered toto albititealbitite oror anaIciteanalcite- A rarerrarer whitwhitee toto lightlight citron-colouredcitron-coloured bearinbearingg rockrock bubutt atat ultra-higultra-highh pressurepressure theythey 123 123 nephrite comescomes fromfrom metasomatitesmetasomatites atat thethe areare alteredaltered ttoo jadeitite.jadeitite. contactcontact zoneszones betweebetweenn deepdeep granitoidsgranitoids andand Diamond inin thethe veryvery largelarge metamorphicmetamorphic dolomites.dolomites. WhitWhitee nephritenephrite maymay bebe depositdeposit neanearr KokchetaKokchetavv [81],[81], northnorth translucenttranslucent ttoo depthsdepths ofof 2 cm.cm. DepositsDeposits suchsuch Kazakhstan,Kazakhstan, occursoccurs asas smallsmall grainsgrains asas BuromskoeBuromskoe [77] andand othersothers occuroccur inin thethe averagingaveraging approximatelyapproximately 3030 pmurn inin sizesize VitimVitim riveriverr valley. (microdiamonds).(microdiamonds). SomeSome crystalscrystals areare cubecube- shaped.shaped. TheThe diamondsdiamonds areare ofof CambrianCambrian ageage Metamorphic rocks of ultra-high pressures Metamorphic rocks of ultra-high pressures andand thethe hosthost rockrockss earlyearly Proterozoic.Proterozoic. SmallSmall Jadeite and chrome-jadeitechrome-jadeite.. LenticularLenticular butbut good-qualitygood-quality diamondsdiamonds areare concentratedconcentrated bodiebodiess andand boudinsboudins ofof jadeititjadeititee areare foundfound inin Cretaceous-TertiaryCretaceous-Tertiary placers.placers. withinwithin AlpineAlpine basite-ultrabasitebasite-ultrabasite massifsmassifs inin the zones of deep faults. Large deposits are at the zones of deep faults. Large deposits are at 3.3. SupergeneSupergene associationsassociations ItmurundyItmurundy [78][78] inin centralcentral Kazakhstan,Kazakhstan, LevokechpelskoeLevokechpelskoe [79][79] inin thethe PolarPolar UralsUrals andand Malachite. TheThe ornamentalornamental materialmaterial KashkarskoeKashkarskoe [80][80] inin thethe westernwestern Sayans.Sayans. malachitemalachite isis bothboth thethe archetypalarchetypal UralsUrals stonestone JadeititeJadeitite isis quitequite commonlycommonly presentpresent inin thethe andand thethe favouritefavourite ofof thethe RussianRussian people!people! marginsmargins ofof enstatiteenstatite oror glaucophaneglaucophane rockrock (Figure 11). High-grade,High-grade, silky-velvet,silky-velvet, wherewhere itit isis accompaniedaccompanied byby albite-albite- andand patternedpatterned malachitemalachite occursoccurs inin thethe residuumresiduum quartz-bearingquartz-bearing rocks.rocks. WhiteWhite andand light-greylight-grey ofof thethe skarnskarn magnetite-chalcopyritemagnetite-chalcopyrite depositsdeposits jadeititejadeitite isis mademade upup ofof almostalmost purepure jadeite.jadeite. inin thethe contactcontact zonezone betweenbetween limestonelimestone Gem-qualityGem-quality emerald-greenemerald-green chrome-bearingchrome-bearing marblemarble andand syenitesyenite atat thethe VysokayaVysokaya omphaciteomphacite andand ferri-omphaciteferri-omphacite (chloro(chloro- mountainmountain inin thethe NizhnyNizhny TagilTagil region;region; melanite)melanite) areare foundfound asas smallsmall areasareas inin thesethese MednorudnyanskoeMednorudnyanskoe [82][82] isis a mainmain producerproducer rocksrocks butbut occuroccur moremore oftenoften asas finefine impregnaimpregna amongamong others.others. LimestoneLimestone isis heavilyheavily karstedkarsted tions.tions. TheThe jadeititejadeitite isis generallygenerally formedformed fromfrom andand thethe sizesize ofof thethe karstkarst cavescaves isis inin thethe regionregion GemGemstonestone ddepositseposits of ththee former Soviet UnionUnion of 140 x 100 x 30 m. The caves are completely quartzites (Figure 13). They occur as separate or partially filled with ferruginated clays with patches and metasomatic segregations of malachite occurring as septaria, patches and irregular form within Carboniferous silicified impregnations, as massive nodules, stalactites limestones locally overlain by Jurassic pyrite- and stalactitic aggregates. The size of some of bearing clays. Good examples are found at the the segregations in the Mednorudyanskoe Golutvin deposit [91] not far from Moscow. deposit reaches an exceptional 4501. This rare type of agate may have formed with Dioptase, sometimes known as 'copper the participation of glacial water. Ornamental- emerald', occurs in the residuum of copper quality agates measure up to 30-50 cm. ores at the Altyn Tiube deposit [83] in Fire opal has been found in the so-called Kazakhstan. It is found as transparent pelikanite: this name has been given to crystals up to 2 cm long (though more often kaolinized granitoids with leached quartz, as 3-7 mm) in limestone marble. found at the Voznesenskoe deposit [92] in Turquoise. There are numerous deposits of north Kazakhstan. Red, orange-red, turquoise in Tadzhkistan, including yellowish-red and other opals form veinlets Biriuzakan [84], in Uzbekistan and patches, the size of absolutely (Kyzylkumskoe [85] and Kalmakyrskoe transparent blocks being in the region of [86]), Armenia (Tekhutskoe [87]) and in the 10x10x4 cm. Vein-like segregations of Polar Urals. It is found in the residuum of semi-transparent opal have been found in phosphate-bearing sedimentary sequences, the clay of recent dumps - it might have been porphyry-copper and gold deposits. possible to watch its formation! Semi- Recently a number of turquoise specimens transparent opal adheres to the tongue; when were found at the Zhilandy deposit [88] near it collects water it becomes completely Ekibastuz, north-east Kazakhstan, where transparent and as water is lost it resumes its they occurred as nodules weighing translucency. This material is very suitable 174 124 exceptionally 1.5 kg though more commonly for polishing. 3-20 g. The inner zone is light-blue zinc-rich Amber. The largest deposit of amber in the turquoise with goyazite as an impurity while world is at Palmnikenskoe [93]. Located near the outer zone is a deep-blue turquoise. It is Kaliningrad-Keniksberg, it produces a bluish penetrated by capillary veinlets of brown amber-bearing sandy clay of Paleogene age rancieite, a hydrated Ca Mn oxide. overlain by Miocene rocks rich in organic Chrysoprase of fine quality forms patches material and Quaternary moraine. This mine and veinlets in birbirite, the name given to a is the world's largest amber producer. weathering crust after carbonatized Freshwater pearl used to be bound in peridotite consisting of limonite, chalcedony nearly all rivers of north European Russia and quartz at the Sarykoulboldy deposit [89] and a large production was necessary to in Kazakhstan. satisfy the demand for the ornamentation of Gypsum. The selenite variety of gypsum dress and for icons. Two large centres of forms as aggregates with long crystals of a production were on the river Kem in Karelia warm pinkish-yellow. Selenite occurs as veins [94] (the coat-of-arms of the town of Kem in the Permian gypsum and salt-bearing clay features a pearl coronet) and on the river formations near the town of Kungur [90]. Dvina [95] where very large pearls have been recovered. Currently the largest formations Flints. Concretions of flint measuring up of freshwater pearls in the world can be to 150 x 150 x 30 cm (usually around 20 cm found in the interior of the Kola peninsula. across) are widespread in the Carboniferous limestone of northern European Russia. Acknowledgements Agate. Fine coloured agates come from interbanded light-grey and milky M. O'Donoghue very kindly assisted in chalcedonies, reddish-brown and gold- the preparation of this paper for publication, reddish-brown sard (carnelian) and bluish and Elisabeth Strack is thanked for J. Gemm., 1998, 26, 2, 111-125 suggestingsuggesting thatthat thethe paperpaper bbee publishedpublished inin thethe Journal.Journal. DDrr I.A.I.A. BaksheevBaksheev (MSU)(MSU) isis thankedthanked forfor translatiotranslationn fromfrom RussianRussian intointo English.English. LONDON DIAMOND FurtheFurtherr ReadinReadingg Bukanov,Bukanov, V.V.,V.V., 1995.1995. Rockcrystal-bearinRockcrystal-bearingg veinveinss ofof ththee REPORT Near-PolarNear-Polar UralsUrals.. World of of Stones, Stones, 7, 77-11, 7-1 1 Bulanova,Bulanova, G.P.,G.P., BarashkovBarashkov,, G.P',G.P., Talnikov,Talnikov, Yu.PYu.P.. etet al., al., 1993. 1993 . NaturalNatural diamond:diamond: geneticgenetic aspectsaspects (in(in Russian).Russian). Novosibirsk, Pub!. Publ Nauka,. Nauka pp, p p168 16 8 Fersman,Fersman, A.E.A.E.,, 1925.1925. PreciousPrecious and and colored colored stones stones of the of USSR the USSR (in(in Russian)Russian) MoscowMoscow.. Pub!.Publ. AcademyAcademy ofof ScienceScience,, USSRUSSR,pp, pp 595922 Fersman,Fersman, A.E.A.E.,, 1954,1954, 1961.1961. Essays on on the the stone stone history history (in (i n Russian).Russian). Moscow.Moscow. PublPub!.. AcademyAcademy ofof Science,Science, USSRUSSR.. 1, pppp 371,371, 2,2, pppp 372372 The Lazarenko,Lazarenko, E.K.E.K.,, Pavlishin,Pavlishin, V.I.,V.I., Latysh,Latysh, V.G.,V.G., et al., 1973.1973. Mineralogy and and genesis genesis of theof thechamber chamber pegmatites, pegmatites, Volyn. Volyn. Gem Testing Lvov.Lvov. PublPub!.. LvoLvovv University,University, pppp 363600 MineralogyMineralogy ofof thethe BaikalBaikal region.region. GuideGuide ofof thethe BaikaBaikall triptrip,, Laboratory 1978.1978. XI Meeting ofof International International Mineral Mineral Association, Association, ppp222p 222 Lomonosov,Lomonosov, 1.5.I.S. (ed).(ed). 1990.1990. GeochemicalGeochemical prospectingprospecting ooff gemsgems (in(in Russian)Russian).. Novosibirsk, Pub!. Publ Nauka,. Nauka pp, p p199 19 9 Rogova,Rogova, V.P.VP.,, Rogov,Rogov, Uy.G.,Uy.G. , andand Drits,Drits, V.A.,VA., 1978.1978 . CharoiteCharoite - newnew mineralmineral andand newnew jeweljewel stonestone (in(in Russian).Russian). Zap.Zap. VMO, 107107 (1),(1), 94-10094-100 Samsonov,Samsonov, Ya.P.Ya.P.,, andand Turinge,Turinge, A.P.,A.P., 1984.1984. Gems of thethe USSR. Moscow.Moscow . Pub!.Publ .Nedra, Nedra, pppp 335335 125 Skrigitil,Skrigitil, A.M.,A.M., 1996.1996. PreciousPrecious stonesstones inin thethe pegmatites,pegmatites, 125 EasternEastern PamirsPamirs.. World of of Stones, Stones, 11, 11, 11-18 11-1 8 Yushkin,Yushkin, N.P.,N.P., IvanovIvanov,, O.K.,O.K., andand Popov,Popov, V.A.,V.A., 19861986.. Introduction to to the the topomineralogy topomineralogy of the of Urals the Urals(Russian). (Russian) . Moscow.Moscow. Pub!.Publ. NaukaNauka,, pppp 294294.. Zhernakov,Zhernakov, V.I.VI.,, 1993.1993. ThThee UralsUrals EmeraldEmerald mineminess (Russian).(Russian). Izvestiya VUZov VUZov - -Corny Gorny Zhurnal, Zhurnal, 11, 1146-52, 46-5 2 Zagorsky,Zagorsky, VE.,V.E., andand PeretyazhkoPeretyazhko,, 1.5.,I.S., 1992.1992. PegmatitesPegmatites withwith gems,gems, CentralCentral TransbaikaliaTransbaikalia (Russian).(Russian). Diamond grading service Novosibirsk, Pub!. Publ Nauka,. Nauka pp, p p187 18 7 Diamonestablishedd gradin ing servic1980 e Zolotukhin,Zolotukhin, F.F.EE,, 1996.1996. The Mariynskoe emeraldemerald deposit. deposit. established in 1980 Middle Urals (Russian)(Russian) St.-Petersburg.St.-Petersburg. Pub!.Publ. St.-PetersburgSt.-Petersburg University,University, pppp 7070.. Each diamond graded by threeEach diamonexperiencedd grade gradersd by three experienced graders Report based on the current Reporinternationalt based on thgradinge curren t proceduresinternationa for colourl gradin andg clarity procedures for colour and clarity Whether buying or selling, theWhethe Londonr buyin Diamondg or selling Report, assuresthe Londo the prestigen Diamon ofd your Repor stonet assures the prestige of your stone The Gem Testing Laboratory of Great Britain GAGTL, 27 Greville street, London EC1N BSU The Gem Testing Laboratory of Great Britain Telephone: 0171·405 3351 Fax: 0171·B31 9479 GAGTL, 27 Greville Street London EC1N 8SU Telephone: 0171-405 3351 Fax: 0171-831 9479 Gemstone deposits deposits of theof theformer former Soviet Soviet Union Union Abstracts Diamonds Synthetics and Simulants Gems and Minerals Synthetics and Simulants Gem news. ilooo.____Diamonds _ _ M.L. JOHNSON AND J.I. KOIVULA. Gems & Gemology, 33(2), 1997, 142-52, 23 illus. in colour. Modem diamond cutting and polishing. A diamond set in a platinum filigree mount was A. CASPI. Gems& Gemology, 33(2),1997, 102-20, 24 illus. in found to be two diamonds placed one on top of another colour. and held together by the claws. J.J. Since 1980 there has been a revolution in the cutting of diamonds, with great advances in the use of modern tech nology, especially in Israel, Belgium, South Africa and Gems and Minerals Russia. The manufacturing component of the final retail value is equal to only 2 per cent. The new advances made Zwei angeblich romische Gemmen aus include a decision support system for marking diamonds, Chalcedon bzw. Mis Sodalith aus dem e.g. deciding where to cut a rough diamond, by using a ehemaligen Jugoslawien. Sarin Dia-Expert System. The rough diamond is shown on a computer screen identifying the best position to mark a F. BRANDSTATTER, W. MELCHART AND G. NIEDERMAYR. stone for cleaving and sawing. Laser kerfing allows a Gemmologie. Zeitschrift der Deutschen Gemmologischen greater precision in following the markers lines, with a Gese/lschaft, 46(2), 1997, 93-5, 2 photographs, 4 126 narrower and shallower kerf being made; also many microphotographs, 1 table, bib!. diamonds may be processed together. Laser mechanical Two cameos of questionable Roman origin were sawing has given rise to greater accuracy and higher found in the former Yugoslavia (Serbia). One was a chal production rates. A bruting laser has also been developed cedony cameo from Sirmium found to be artificially and is mostly used for fancy cut diamonds. J.J. coloured blue. Although the Romans had dark-blue to grey-blue gems, we have no examples of their colouring Gem TradeLab notes. agates and chalcedonies blue. The second cameo was reported to come from Viminacium and was identified as C.W. FRYER. Gems & Gemology, 33(2),1997,134-41,19 illus. transparent sodalite, similar to material discovered in in colour. 1973 in Namibia. The cameos themselves and the way A yellow heart-shaped diamond was found to have a they were produced closely resemble genuine Roman distinct orange patch of colour, which was caused by a gems - the materials used, however, showed them to be limonitic stain to a fracture. It should be possible to fakes. E.S. remove the stain by boiling in acid. A green and pink rough diamond showed properties of a natural pink Broken Hill. diamond. The green colour arose from green radiation stains from natural radiation, which did not penetrate the AustralianJournal of Mineralogy, 3(1), special issue, 1997, body. Yellow to yellowish-green treated diamonds were 87 pp, illus. in colour. found to have been treated possibly by a new method A number of gem-quality species are found at Broken using very high temperatures (>1400°C).These diamonds Hill, New South Wales. This is a thematic rather than a showed a frosted burnt appearance on the facet junctions special issue of the journal since it is not outside the part and a peak at 985 nm (not visible with a spectroscope) numbering, and contains papers on some notable cabinets caused by the H2 centre, otherwise they exhibited many (fine gem-quality crystals from the Milton Lavers properties normally associated with natural diamonds. collection are illustrated) and on species recently obtained J.J. from the Kintore and Block 14 open cuts at the mine: Abstractors R.A. Howie R.A.H. M. O'Donoghue M.O'D. E.Stern E.S. J. Johnson J.j. P.G. Read P.G.R. I. Sunagawa i.s. For further information on many of the topics referred to, consult Mineralogical Abstracts. © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355-4565 collectorscollectors ofof micromountsmicromounts willwill be be especiallyespecially interestedinterested inin AA quartzquartz cat's-eyecat's-eye effecteffect waswas causedcaused byby largelarge rutilerutile thethe range range of of species species found. found . PapersPapers havehave their their ownown lists lists of of needles:needles : itit waswas concludedconcluded thatthat thesethese stonesstones shouldshould bebe references.references . M.O'D.M.O'D . knownknown asas cat's-eye cat's-eye rutilated rutilated quartz.quartz . J.J.J.J . Puiva:Puiva : GwindelGwindel undund AxinitAxinit ausaus demdem Polar-Ural.Polar-Ural . GemGem TradeTrade LabLab notes.notes . J.v.J.V .BURLAKOV. BURLAKOV .Lapis, Lapis, 22(7/8), 22(7/8) 1997,, 1997 59-70,, 59-70 illus., illus in. i ncolour, colour , c.w.C.W .FRYER. FRYER .Gems Gems & &Gemology, Gemology, 33(2),1997,134-41,19 33(2), 1997,134-41,1 illus.9 illus . 22 maps. maps . inin colour. colour . FineFine crystals crystals ofof ferroaxiniteferroaxinite andand ofof quartzquartz withwith thethe soso- AnAn unusualunusual doubletdoublet composedcomposed ofof a a fully fully facetedfaceted berylberyl calledcalled 'gwindel''gwindel ' habithabit areare described,described , withwith otherother minerals,minerals , overover which which a a green green plastic plastic layer layer had had been been added added toto give give an an fromfrom thethe Puiva Puiva area area of of the the Polar Polar Urals Urals of of Russia. Russia . M.O'D.M.O'D . emeraldemerald colourcolour andand extraextra depthdepth hadhad aa convincingconvincing appearance.appearance .Another Another unusual unusual stone stone was was a a dark dark brown, brown ,oval ova l Pridorozhnoje:Pridorozhnoje: MorionfundeMorionfunde imim Polar-Ural.Polar-Ural . cabochoncabochon feldspar,feldspar , whichwhich exhibitedexhibited aa four-rayedfour-rayed starstar andand two parallel bands of chatoyancy. A variegated banded J.V.J.V .BURLAKOV. BURLAKOV .Lapis, Lapis, 22(7/8),1997,71-4, 22(7/8), 1997, 71^ ,illus. illus in. i ncolour. colour . two parallel bands of chatoyancy. A variegated banded brown,brown ,white white and and light-green light-green bead bead necklace necklace was was composed composed FineFine crystals crystals ofof morionmorion (smoky(smoky quartz)quartz) areare described described ofof naturally-colourednaturally-coloured jadeite;jadeite ;it it waswas probablyprobably cutcut fromfrom thethe fromfrom PridorozhnojePridorozhnoje inin the the Russian Russian PolarPolar Urals. Urals .Occurring Occurring outsideoutside layer layer ofof aa naturally naturally stainedstained jadeitejadeite boulder.A boulder.A heatheat- inin AlpineAlpine cleft-typecleft-type deposits,deposits , crystalscrystals maymay reachreach upup toto treatedtreated blueblue sapphiresapphire showedshowed allal l thethe diagnosticdiagnostic featuresfeatures 1515 cmcm in in length. length .Other Other mineralsminerals from from thethe area area are are listed. listed . togethertogether withwith a a raised raised areaarea on on the the culet, culet ,which which was was part part ofof M.O'D.M.O'D . thethe originaloriginal heat-treated heat-treated surface.surface . AA small smal ldark dark greengreen stonestone waswas identified identified asas a a very very rare rare mineral mineral known known as as serendibite, serendibite , DieDie SmaragdgrubenSmaragdgruben desdes Urals:Urals :Tokowaja Tokowaja- withwith biaxial biaxia lRIs RIs ofof 1.697 1.697 and and 1.704, 1.704 ,a a weak weak absorption absorption line line at a t Malyshevo. Malyshevo. 470470 nmnm and and no no fluorescence.fluorescence .Unusually Unusually a a dark dark brown brown zircon zircon JV.J.V. BURLAKOV,BURLAKOV , J.A.J.A. POLENOV,POLENOV , v.J.V.J. GERNAKOVGERNAKOV ANDAND A.v.A.V . cabochoncabochon exhibitedexhibited aa playplay ofof colourcolour showingshowing flashesflashes ofof SAMSONOV.SAMSONOV .Lapis, Lapis, 22(7/8), 22(7/8) 1997,44-55,, 1997, 44-55 illus., illus in. i ncolour, colour , greengreen andand red,red , similarsimilar toto anan opal.opal .The The cause cause ofof thethe colourcolour 22 maps. maps . waswas not not determined. determined . J.J.J.J . SuperbSuperb crystalscrystals ofof emeraldemerald andand alexandritealexandrite withwith aa veryvery markedmarked colour-changecolour-change areare describeddescribed fromfrom thethe MineraliMinerali inin vetrina:vetrina : alcunealcune tormalinetormaline delladella Tokowaja-Malyshevo area of the Russian Urals. Tokowaja-Malyshevo area of the Russian Urals. collezionecollezione GiazottoGiazotto [second[second part].part] . SpecimensSpecimens fromfrom thethe FersmanFersman MineralogicalMineralogical Museum,Museum , Moscow, are illustrated: the geology and the A.A .GIAZOTTO. GIAZOTTO .Rivista Rivista mineralogica mineralogica italiana, italiana, 16,1993,93-101, 16,1993, 93-101 , Moscow, are illustrated: the geology and the illus. in colour. mineralizationmineralization ofof thethe areaarea areare described,described , mostmost emeraldemerald illus. in colour. 127127 andand alexandritealexandrite beingbeing recoveredrecovered fromfrom micamica schists.schists . TourmalineTourmaline crystals crystals from from pegmatitespegmatites of of the the Gilgit Gilgit area area Yellow-greenYellow-green chrysoberyl chrysoberyl is is also also found. found . OtherOther minerals minerals of of ofof Pakistan,Pakistan, fromfrom Madagascar,Madagascar, Nepal,Nepal , Mozambique,Mozambique , interestinterest toto thethe gemmologistgemmologist includeinclude euclase,euclase , topaz,topaz , CaliforniaCalifornia andand BrazilBrazil are are described described andand illustrated.illustrated . phenakite,phenakite ,beryl beryl and and apatite.apatite . M.O'D.M.O'D . M.O'D.M.O'D . Mines and minerals of Peru. Mines and minerals of Peru. LaLa cueillette cueillette desdes minerauxminéraux gemmesgemmes dudu massifmassif J.A.J.A. CROWLEY,CROWLEY , R.H.R.H. CURRIERCURRIER ANDAND T. T . SZENICS.SZENICS .Mineralogical Mineralogical dudu Mont-Blanc.Mont-Blanc . Record,Record, 28(4),1997,7-98, 28(4), 1997, 7-98 illus., illus in. icolour.n colour . E.E .GONTHIER. GONTHIER . RevueRevue de de Gemmologie, Gemmologie, 131, 131,1997,21-4 1997,21-4. . Among the minerals of Peru, fine crystals of fluorite Among the minerals of Peru, fine crystals of fluorite The geology and mineralization of the Mont Blanc andand rhodochrositerhodochrosite areare mostmost likelylikely toto interestinterest thethe The geology and mineralization of the Mont Blanc massifmassif areare describeddescribed withwith particularparticular referencereference toto thethe gemmologist.gemmologist . TheThe differentdifferent miningmining districtsdistricts ofof PeruPeru areare described with geological and mine maps: details of the occurrenceoccurrence of of gem-quality gem-quality crystals: crystals :fine fine crystals crystals of of fluorite fluorite described with geological and mine maps: details of the are especially notable. M.O'D. geologygeology andand mineralizationmineralization areare givengiven inin allal l casescases andand are especially notable. M.O'D. therethere is is a a useful useful bibliography.bibliography . M.O'D.M.O'D . RubiesRubies andand fancyfancy colouredcoloured sapphiressapphires fromfrom GIA Gem Trade Lab notes. GIA Gem Trade Lab notes. Nepal.Nepal. C.W. FRYER (ed.). Gems & Gemology, 33(1), 1997, 54-9. c.w. FRYER (ed.). Gems & Gemology, 33(1), 1997, 54-9. E.J.E.J. GOBELIN,GÜBELIN ,A.M. A.M. BASSETTBASSETT AND AND M.N. M.N. MANANDHAR.MANANDHAR .Gems Gems & & AA redred andand yellowyellow semi-translucentsemi-translucent portraitportrait ofof aa Gemology,Gemology, 33(1), 33(1) 1997,, 1997 24-41,, 24-41 26, 2coloured6 coloure illustrations,d illustrations , BuddhaBuddha provedproved toto be be 'hornbill'hornbill ivory'ivory ' fromfrom thethe helmetedhelmeted 22 tables. tables . hornbill.hornbill . TheThe mostmost diagnosticdiagnostic featurefeature ofof thisthis organicorganic AlthoughAlthough NepalNepal isis not not aa major major sourcesource ofof gem-qualitygem-quality materialmaterial isis the the bright bright redred borderborder ofof the the yellow yellow helmet. helmet . corundum,corundum, itit doesdoes produceproduce somesome unusualunusual rubiesrubies andand ThreeThree largelarge baroquebaroque beadsbeads whichwhich werewere reportedreported toto fancy coloured sapphires, together with a broad range of have belonged to the Mogul emperor Alban Shah fancy coloured sapphires, together with a broad range of have belonged to the Mogul emperor Alban Shah gemstones.gemstones .The The corundum corundum isis found found asas a a primary primary depositdeposit (1542-1605)(1542-1605 ) werewere identifiedidentified asas spinel,spinel , sapphiresapphire andand aa in the Dhading District in Nepal in isolated dolomite green aquamarine. The hand drilling, the inscribing of the in the Dhading District in Nepal in isolated dolomite green aquamarine. The hand drilling, the inscribing of the pods,pods , whichwhich havehave beenbeen subjectedsubjected toto low-gradelow-grade metameta- MogulMogul namesnames andand thethe colourcolour ofof thethe aquamarineaquamarine lentlent morphism. The exploration and mining of the gemstones credence to their provenance. morphism. The exploration and mining of the gemstones credence to their provenance. havehave beenbeen sporadicsporadic duedue toto thethe terrainterrain andand thethe harshharsh AA piece piece of of roughrough andand aa cabochon-cut,cabochon-cut , greenish-yellowgreenish-yellow climate.climate . MostMost stonesstones areare cutcut asas cabochonscabochons withwith aa veryvery opalopal showed showed aa chatoyant chatoyant effect effect causedcaused by by linear linear inclusions. inclusions . smallsmall percentage percentage of of higher higher gemgem quality quality faceted.faceted . AbstractsAbstracts - Gems- Gems and and Minerals Minerals MuchMuch ofof thethe corundumcorundum isis similarsimilar ttoo thatthat foundfound iinn DrusyDrusy iridescentiridescent pyritepyrite fromfrom RussiaRussia.. ThiThiss neneww otheotherr marblemarble typetype deposits,deposits, bubutt therethere areare somesome notablenotable materialmaterial isis formedformed asas crystalscrystals lininglining concretionsconcretions anandd differencedifferencess withwith inclusionsinclusions comprisingcomprising densedense concentraconcentra foundfound inin thethe bedbed ofof thethe RiverRiver VolgaVolga iinn Russia.Russia. QuartzQuartz withwith tiontionss ofof veryvery finefine shortshort rutilrutilee needlesneedles,, rod-shapedrod-shaped apatiteapatite 'rainbow''rainbow' hematitehematite inclusionsinclusions comescomes fromfrom ththee AldanAldan crystals,crystals, colourlesscolourless margaritemargarite,, anorthiteanorthite feldsparfeldspar anandd uviteuvite MountainsMountains inin Yakutia.Yakutia. TheThe inclusionsinclusions araree hexagonahexagonall ttoo tourmalinetourmaline;; distinctdistinct colourcolour zoninzoningg isis commoncommon andand therethere irregular,irregular, withwith thethe thinnerthinner inclusionsinclusions appearingappearing redred,, whilewhile areare bicolourbicolour stonesstones withwith redred andand violetish-bluevioletish-blue zoneszones iinn ththee thickethickerr inclusionsinclusions appearappear blacblackk andand opaque.opaque. thicthickk oror wedge-shapedwedge-shaped bandsbands;; alsoalso therethere areare almostalmost AventurescenceAventurescence inin somesome rockrock crystalcrystal mamayy arisarisee fromfrom colourlescolourlesss haloshalos surroundedsurrounded bbyy mineralmineral inclusions.inclusions. pyritpyritee inclusions.inclusions. ToTo obtainobtain thethe desireddesired effeceffectt specificspecific orientationorientation ofof thethe inclusioinclusionn planeplane jusjustt offoff paralleparallell ttoo thethe Also found in Nepal are trapiche corundums with Also found in Nepal are trapiche corundums with tabletable facetfacet isis needed.needed. raysrays formedformed ofof phologopitephologopite,, apatite,apatite, calcitecalcite andand graphitegraphite whichwhich differdiffer fromfrom thosethose ofof otherother localities.localities. J.JJ.J.. A veryvery vividvivid orangeorange naturalnatural sapphiresapphire frofromm TunduruTunduru regioregionn ofof TanzaniaTanzania wawass beingbeing exhibited,exhibited, bubutt iitt wawass nonott knowknownn whetherwhether itit hadhad beenbeen heatheat treatedtreated.. AlsAlsoo fromfrom ththee GemmologischeGemmologische Kurzinformationen.Kurzinformationen. regioregionn werewere peridotperidot,, unusuallunusuallyy colouredcoloured grossulargrossular anandd ShortShort gemmologicalgemmological notesnotes.. spinels.spinels. OneOne veryvery largelarge tanzanitetanzanite hahadd a fluifluidd inclusioninclusion witwithh a movablemovable gasgas bubble.bubble. U.U. HENNHENN ANDAND c.c.C.C . MILISENDA.MILISENDA. SmaragdeSmaragde ausaus ChinaChina [Emeralds[Emeralds fromfrom Chinal.China]. Gemmologie. Z. Dt. Gemmol. FineFine gemgem tourmalinetourmaline fromfrom thethe NeNeuu SchwabeSchwabenn region,region, Ges.,Ges., 46(2),109-12.46(2), 109-12. NamibiaNamibia,, isis expectedexpected toto comecome ontoonto ththee marketmarket.. ThThee colourscolours areare mainlymainly greens,greens, blubluee andand blue-greeblue-greenn witwithh onlyonly TheThe emeraldsemeralds comecome fromfrom Malipo,Malipo, 300300 kmkm southsouth ooff facetfacet gradegrade materialmaterial toto bebe marketed.marketed. Kunming,Kunming, nearnear thethe VietnameseVietnamese border.border. TheThe samplessamples occuroccur iinn micamica schistsschists withwith quartzquartz andand fluorite;fluorite; theythey showshow longlong A greengreen andand blackblack nephritenephrite withwith magnetitmagnetitee inclusionsinclusions prismatiprismaticc crystalscrystals uupp toto 3 cm,cm, mostlymostly heavilyheavily included,included, fromfrom Victorville,Victorville, California,California, hashas beenbeen electroplatedelectroplated withwith translucentranslucentt withwith anan attractiveattractive greengreen colour;colour; darkdark needleneedle- ththee goldgold adheringadhering toto thethe magnetite.magnetite. J.JJ.J.. shapedshaped tourmalinetourmaline inclusionsinclusions areare visiblevisible toto thethe nakednaked eye.eye. A fewfew smallersmaller crystalscrystals werewere transparenttransparent andand ofof gemgem GemGem newsnews qualityquality.. RIRI 1.573-1.5751.573-1.575 toto 1.580-1.583,1.580-1.583, DRDR 0.007-0.008,0.007-0.008, M.L.M.L. JOHNSONJOHNSON ANDAND J.1.J.I. KOIVULA.KOIVULA. Gems & Gemology, 33(2)33(2),, SGSG 2.68-2.71.2.68-2.71. ApartApart fromfrom ththee tourmalinetourmaline inclusions,inclusions, finefine 1997,1997,142-52,2 142-52, 233 illus.illus. inin colour.colour. crackscracks asas wellwell asas distinctdistinct growthgrowth zoningzoning werewere visiblevisible underunder thethe microscope.microscope. A minemine nearnear Patna,Patna, BiharBihar State,State, India,India, produceproducess moonmoon 128128 stonesstones withwith a 'royal''royal' blueblue sheen.sheen. MuchMuch ofof ththee googoodd qualityquality U.U. HENNHENN ANDAND H.H. BANK.BANK. Beryll-KatzenaugeBeryll-Katzenaugenn undund materiamateriall isis 1 ctct oror less.less. PropertiesProperties ofof ththee stonestoness areare consistentconsistent Sternberylle.Sternberylle. Cat's-eyeCat's-eye berylsberyls andand starstar beryls.beryls. witwithh labradoritelabradorite oror bytownitebytownite (high(high calciumcalcium plagioclase)plagioclase).. A Gemmologie. Z. Dt. Gemmo/.Gemmol. Ges., 46(2),113-17.46(2), 113-17. brownish-purplbrownish-purplee stonestone waswas identifiedidentified asas ververyy rarerare TheThe cat's-eyecat's-eye effecteffect isis describeddescribed inin aquamarines,aquamarines, goldengolden musgravitemusgravite,, a closeclose relativrelativee ofof taaffeite.taaffeite. A neneww emeraldemerald fillerfiller berylsberyls,, morganites,morganites, emeralds;emeralds; thisthis isis causedcaused byby parallelparallel hashas beenbeen developeddeveloped andand isis reputedreputed toto havhavee bettebetterr propertiesproperties needle-likeneedle-like inclusions,inclusions, especiallyespecially holloholloww tubes.tubes. AsterismAsterism iiss thanthan Opticon.Opticon. TheThe newnew fillerfiller consistsconsists ooff a resiresinn andand hardhard duedue toto mineralmineral inclusionsinclusions oror fluidsfluids orientedoriented inin layerslayers parallelparallel eningening agentagent andand doesdoes notnot turnturn yellowyellow witwithh timetime.. J.JJ.J.. toto thethe crystalcrystal basbasee andand isis describeddescribed asas occurringoccurring inin aquaaqua marinemariness andand veryvery rarelyrarely inin emeralds.emeralds. E.SE.S.. BrasilianischeBrasilianische OpaleOpale ausaus PedroPedro IIII.. GemGem newsnews fromfrom TucsonTucson 1997.1997. J.J. KNIGGEKNIGGE ANDAND c.c.C.C. MILISENDA.MILISENDA. Gemmologie. Zeitschrift der Deutschen Gemmologie Gesellschaft, 46(2)46(2),1997,99-105,, 1997, 99-105, MXM.L.. JOHNSOJOHNSONN ANDAND J.1.J.I. KOIVULAKOIVULA (Eds.).(Eds.). Gems & Gemology, 8 photos,photos, bib!.bibl. 33(1),1997,60-70,2733(1), 1997, 60-70, 27 colouredcoloured illustrations.illustrations. TheThe PiauiPiaui StateState isis thethe onlyonly placplacee iinn BraziBrazill wherwheree gemgem- Gem-qualityGem-quality andraditesandradites werewere forfor salesale fromfrom a newnew qualityquality opalsopals havehave beenbeen minedmined inin commercialcommercial quantities;quantities; localitylocality iinn Arizona,Arizona, nonott farfar fromfrom ththee StanleyStanley ButteButte locality,locality, althoughalthough thesethese opalsopals areare ofof highhigh quality,quality, ththee importanceimportance ooff whicwhichh hashas produceproducedd non-gemnon-gem andraditeandradite forfor somesome years.years. thesthesee occurrencesoccurrences hashas decreaseddecreased dramaticallydramatically durinduringg thethe AllAll thethe andraditesandradites showedshowed typicatypicall propertiesproperties butbut nnoo paspastt fewfew yearsyears asas onlyonly veryvery smallsmall quantitiequantitiess araree nownow 'horsetail''horsetail' inclusionsinclusions werweree observed.observed. produced.produced. TheThe minesmines areare locatedlocated withiwithinn a radiuradiuss ooff 5500 kmkm AnAn unusualunusual trapichetrapiche emeraldemerald fromfrom ColombiaColombia ofof PedroPedro IIII whichwhich isis aboutabout 200200 kmkm awaawayy fromfrom ththee capital,capital, exhibitedexhibited twotwo centralcentral columnscolumns eacheach withwith blackblack spokesspokes thatthat Teresina.Teresina. ExceptExcept forfor thethe BoiBo i MortoMorto minminee alalll opalopalss araree extendedextended througthroughh thethe lengthlength ofof thethe stone.stone. JetJet isis nownow beingbeing recovererecoveredd fromfrom secondarysecondary deposits.deposits. AAtt BoBoi i MortMortoo ththee quarriedquarried atat MataganMatagan neanearr LakLakee Baikal,Baikal, northnorth ofof Irkutsk,Irkutsk, stonesstones areare foundfound atat a sandstonesandstone quartz-doleritquartz-doleritee contact.contact. InIn somesome ofof thethe jejett waswas jusjustt massivemassive lumpslumps ofof roughrough andand somesome contrastcontrast toto thethe BoBoii MortoMorto opalsopals thethe alluvialalluvial stonesstones showshow nono hadhad beenbeen carved.carved. ManyMany cabochonscabochons ofof bicolour-labradoritebicolour-labradorite signssigns ofof crackingcracking duedue ttoo thethe relativelyrelatively loloww watewaterr content.content. werewere beingbeing marketedmarketed inin differentdifferent shapesshapes andand sizes,sizes, aass MosMostt opalsopals areare translucenttranslucent toto semi-transparentsemi-transparent anandd whitewhite werewere 'Rainbow''Rainbow' obsidianobsidian heartshearts.. BotryoidalBotryoidal whitewhite opalopal ttoo whitish;whitish; bodybody colourscolours includeinclude white,white, reddishreddish,, orangy,orangy, fromfrom Milford,Milford, UtahUtah,, hahass beenbeen onon thethe marketmarket forfor atat leastleast yellowyellow,, greenishgreenish andand bluish.bluish. SomeSome materiamateriall hahass a veryvery twentytwenty yearyearss andand isis sometimessometimes knownknown asas satinsatin flashflash opa!.opal. distinctivedistinctive layerlayer structurestructure inin itsits bodybody colourcolour andand play-ofplay-of- SimilarSimilar opalopal fromfrom UtahUtah bandedbanded inin translucenttranslucent toto transtrans colourcolour resemblingresembling syntheticsynthetic opals,opals, butbut witwithh nnoo lizard-skinlizard-skin parentparent whitewhite isis alsoalso nonoww onon thethe market.market. effect.effect. E.SE.s.. J./. Gemm., 1998,1998,26, 26, 2,2,126-131 126-131 GemGem rhodochrositerhodochrosite fromfrom thethe SweetSweet HomeHome MineMine,, RubisRubis etet saphirssaphirs dudu Viêt-NamViet-Nam.. Colorado.Colorado. J.-P.J.-P. POIROT.POIROT. Revue de de Gemm%gie, Gemmologie, 131, 131,1997,3-5, 1997,3-5,1 map.1 map . K.K. KNoxKNOX ANDAND B.KB.K.. LEESLEES.. Gems && Gemology, Gemology, 33(2), 33(2) 1997,, 1997 , AnAn overviewoverview ofof rubrubyy andand blueblue sapphiresapphire productionproduction iinn 122-33,122-33,1 155 illus.illus. iinn colour,colour, 1 tabletable.. VietnamVietnam withwith detailsdetails ofof thethe specimensspecimens found.found. NoteNotess oonn characteristiccharacteristic inclusionsinclusions areare given.given. M.O'DM.O'D.. SomeSome ofof ththee finestfinest transparenttransparent vividvivid redred rhodochrositerhodochrosite hahass beebeenn foundfound inin ththee SweetSweet HomeHome Mine,Mine, inin thethe MosquitoMosquito RangeRange inin Colorado.Colorado. TheThe minemine isis situatedsituated 11,60011,600 ftft aboveabove DasDas GeologischeGeologische MuseuMuseumm vonvon JekaterinburgJekaterinburg imim seasea levellevel andand isis onlyonly accessiblaccessiblee twotwo ttoo threethree monthmonthss a yearyear.. Ural.Ural. TheThe geologygeology ofof thethe areaarea isis PrecambrianPrecambrian granitegranite andand gneissgneiss,, J.A.J.A. POLENOV,POLENOV, J.V.J.V. BURLAKOBURLAKOVV ANDAND V.NV.N.. AVOONIN.AVDONIN. Lapis,Lapis, whichwhich werewere intrudedintruded 3030 millionmillion yearsyears agoago bbyy a magmamagma 22(7/8),1997,56-8,22(7/8), 1997, 56-8, illus.illus. inin colour.colour. thathatt formedformed a porphyry-molybdenuporphyry-molybdenumm system.system. TheThe veinsveins areare polymetallipolymetallicc (silver,(silver, lead,lead, zinczinc andand copper)copper) andand followfollow SomeSome ofof thethe mineralmineral specimensspecimens inin thethe collectionscollections ooff a NENE trendtrend withwith thethe rhodochrositerhodochrosite formingforming asas a ganguegangue thethe GeologicalGeological MuseumMuseum atat EkaterinburgEkaterinburg (formerly(formerly mineraminerall inin pocketspockets.. Sverdlovsk)Sverdlovsk) areare described.described. OneOne largelarge rockrock crystalcrystal reachesreaches 1.71.7 m inin heightheight andand a numbernumber ofof typetype specimens,specimens, MiningMining wawass originallyoriginally forfor silversilver bubutt whenwhen itit becamebecame includingincluding uvarovite,uvarovite, areare alsoalso held.held. M.O'D.M.O'D. unproductiveunproductive miningmining switchedswitched toto rhodochrositrhodochrositee inin 19661966.. ThisThis wawass irregularirregular untiuntill betterbetter geologicalgeological mappingmapping waswas ColourlessColourless diopsidediopside andand tremolite:tremolite: twotwo newnew used,used, andand GroundGround PenetratinPenetratingg RadarRadar (GPR)(GPR) ttoo locatelocate thethe pockets.pockets. AlsoAlso specialspecial toolstools andand collectingcollecting techniquestechniques hadhad 'end-member''end-member' gemsgems fromfrom Canada.Canada. ttoo bebe developeddeveloped ttoo preventprevent damagedamage ttoo ththee stones.stones. TToo datedate G.G. ROBINSONROBINSON ANDAND WW.. WIGHT.WIGHT. Canadian Gemma/agist, Gemmologist, 18, 18, 9090 peperr centcent ofof thethe pocketpocketss havehave beebeenn foundfound toto bebe ofof littlelittle 1997,45-9.1997,45-9. commercialcommercial valuevalue,, butbut approximatelyapproximately a hundrehundredd 0.500.50 ctct++ DiopsideDiopside andand tremolittremolitee areare reportedreported andand describeddescribed stonesstones a yearyear areare cutcut.. DuDuee toto itsits cleavagecleavage andand softnesssoftness itit isis fromfrom rocksrocks ofof thethe GrenvilleGrenville geologicalgeological province,province, a beltbelt ooff a difficultdifficult stonestone toto facetfacet andand hashas toto bebe setset withwith greatgreat care.care. igneousigneous andand metamorphicmetamorphic rocksrocks extendingextending fromfrom southsouth CuttingCutting isis slowslow andand hashas toto bebe donedone bbyy handhand.. AsAs mininminingg iiss easterneastern OntarioOntario toto northernnorthern Quebec.Quebec. ThatThat partpart ofof thethe problematicaproblematicall ththee futurfuturee ofof thethe SweetSweet HomeHome MinMinee iiss provinceprovince knownknown asas ththee CentralCentral MetasedimentaryMetasedimentary BelBeltt dependentdependent onon advanceadvancess inin methodsmethods usedused foforr geologicalgeological hostshosts a numbernumber ofof gem-qualitygem-quality minerals.minerals. DiopsideDiopside ooff exploration.exploration. J.JJ.J.. gemgem qualityquality occursoccurs atat LotLot 22,22, RangeRange IIII,, CawoodCawood Township,Township, PontiacPontiac County,County, Quebec.Quebec. ConstantsConstants areare givengiven 129 Geographie,Geographie, BergbauBergbau,, GeologieGeologie undund forfor thethe rarerare colourlesscolourless material:material: whitewhite opaqueopaque materialmaterial 129 occurs more commonly. Colourless tremolite of gem LagerstattenLagerstätten desdes UralsUrals.. occurs more commonly. Colourless tremolite of gem qualityquality isis foundfound onon thethe DanceyDancey FarmFarm nearnear Irondale,Irondale, P.P. KOLESAR.KOLESAR. Lapis, 22(7/8), 22(7/8) ,1997, 1997 ,13-24, 13-24 ,illus. illus .in in colour, colour ,3 3 SnowdonSnowdon Township,Township, HaliburtonHaliburton County,County, Ontario:Ontario: maps.maps. constantsconstants areare given.given. BothBoth mineralsminerals areare nearnear toto endend- membermember composition.composition. M.O'DM.O'D.. TheThe UraUrall mountainsmountains extendextend overover 20002000 kmkm inin lengthlength andand containcontain a numbernumber ofof majormajor preciousprecious metametall andand gemstonegemstone deposits.deposits. TheThe skarnskarn depositsdeposits andand pegmatitepegmatitess ooff NeuerNeuer spektakularerspektakulärer AmethystfundAmethystfund ausaus MursinkaMursinka areare describeddescribed inin somesome detail:detail: thisthis areaarea producesproduces Siidnorwegen.Südnorwegen. aquamarine,aquamarine, heliodor,heliodor, finefine specimensspecimens ofof rockrock crystalcrystal andand amethystamethyst andand isis welwelll knownknown forfor museummuseum qualityquality F.F. STEINARSTEINAR NORDRUM,NORDRUM, A.O.A.O. LARSEN,LARSEN, T.T. BERGSTROMBERGSTROM ANDAND examplesexamples ofof blueblue topaz.topaz. M.O'DM.O'D.. S.S. LARSEN.LARSEN. Mineralien Welt, Welt, 8(4), 8(4) 1997,45-50,1, 1997,45-50, map.1 map . LargeLarge well-formedwell-formed crystalscrystals ofof amethystamethyst areare reportedreported frofromm Holmestrand,Holmestrand, southsouth Norway.Norway. ManyMany ofof thethe crystalscrystals NewNew emeraldemerald depositsdeposits fromfrom SouthernSouthern IndiaIndia.. showshow sceptresceptre form:form: detailsdetails ofof thethe mineralizationmineralization ofof thethe J.J. PANjIKAR,PANJIKAR, K.TK.T.. RAMCHANDRARAMCHANDRANN ANDAND K.K. BALU.BALU. Australian areaarea andand otherother mineralsminerals areare described.described. M.O'D.M.O'D. Gemmologist, 19(10), 19(10) 1997,, 1997,427-32, 427-32, 1 illus.1 illus in. black-andin black-and- whitewhite,, 1 graph,graph, 3 tablestables.. UpdateUpdate onon emeraldsemeralds fromfrom thethe SandawanaSandawana EarlyEarly inin 19951995 emeraldsemeralds werewere discovereddiscovered onon ththee innerinner Mines,Mines, Zimbabwe.Zimbabwe. wallwallss ofof a welwelll inin ththee villagvillagee ofof SankariSankari TalukaTaluka inin SouthernSouthern India'sIndia's statestate ofof TamiTamill Nadu.Nadu. ThisThis initialinitial discoverydiscovery leledd toto J.e.J.C ZWAAN,ZWAAN, J.J. KANISKANIS ANDAND E.J.E.J. PETSCH.PETSCH. Gems && Gem%gy,Gemology, furtherfurther explorationexploration whicwhichh uncovereduncovered depositsdeposits iinn thethe 33(2),1997,80-100,3133(2), 1997, 80-100,31 illus.illus. inin colour,colour, 44 tables.tables. SalemSalem districtdistrict ofof TamiTamill NaduNadu state.state. InvestigationInvestigation intointo thethe SinceSince 19651965 emeraldsemeralds havehave beenbeen minedmined atat SandawanaSandawana propertiesproperties ofof thethe emeraldsemeralds andand theirtheir characteristiccharacteristic whichwhich isis situatedsituated inin thethe MberengwaMberengwa districtdistrict inin southernsouthern inclusionsinclusions havhavee revealerevealedd similaritiessimilarities betweebetweenn thethemm andand Zimbabwe.Zimbabwe. EmeraldsEmeralds areare foundfound alongalong thethe southernsouthern thethe emeraldsemeralds fromfrom severalseveral locationslocations inin Madagascar.Madagascar. ThiThiss limitslimits ofof thethe archaeanarchaean ZimbabweZimbabwe craton,craton, withinwithin thethe suggestssuggests thathatt thethe SankariSankari emeraldsemeralds maymay havhavee beenbeen greenstonegreenstone beltbelt,, whicwhichh isis composedcomposed ofof a seriesseries ooff emplacedemplaced intointo ththee ancientancient supercontinentsupercontinent ooff intenselyintensely deformeddeformed metamorphic,metamorphic, maficmafic volcanicvolcanic rocksrocks GondwanalandGondwanaland beforbeforee IndiaIndia separatedseparated fromfrom itit andand thethe andand pegmatites.pegmatites. TheThe emeraldsemeralds occuroccur nearnear thethe pegmatitespegmatites nascennascentt islandisland ofof MadagascarMadagascar somesome 2020 millionmillion yearyearss agoago.. especiallyespecially wherewhere theythey areare inin contactcontact withwith thethe ultramaficultramafic P.G.RP.G.R.. rocksrocks (komatiites).(komatiites). Abstracts - -Gems Gems and and Minerals Minerals MuchMuch ofof thethe emeraldemerald produceproducedd isis small,small, lessless thanthan 0.500.50 FlattenedFlattened diamonddiamond crystalscrystals werewere synthesizedsynthesized underunder ctct,, andand mostmost isis lessless thanthan 0.250.25 ct.ct. TheThe emeraldsemeralds areare a vividvivid highighh oxygenoxygen gasgas concentrationconcentration anandd lowlow substratsubstratee T. greegreenn andand normallynormally showshow anan eveneven colourcolour distribution.distribution. PreferentialPreferential growthgrowth alongalong sideside facesfaces duedue ttoo ththee presencpresencee ofof OtheOtherr typicaltypical characteristicscharacteristics areare a highhigh RIRI (n,(ne 1.584-1.587,1.584-1.587, twintwin re-entrantre-entrant corners,corners, andand thethe factfact thathatt a {Ill}{111} facfacee iiss nnroœ 1.590-1.594)1.590-1.594) andand a highhigh SGSG (2.74-2.77).(2.74-2.77). MostMost stonesstones orientedoriented IIII thethe substratesubstrate surfacesurface duedue ttoo texturtexturee growtgrowthh iinn containcontain fibrousfibrous amphibole,amphibole, bothboth actinoliteactinolite andand thethe earlyearly stagestage ofof nucleation,nucleation, areare responsibleresponsible forfor ththee flatflat cummingtonitecummingtonite.. FluidFluid inclusionsinclusions areare notnot commoncommon andand areare tenetenedd morphology.morphology. SEMSEM observationsobservations andand RamaRamann spectrospectro usuallyusually presentpresent asas partiallpartiallyy healedhealed fractures.fractures. TheThe scopicscopic measurementsmeasurements indicatedindicated thatthat ththee diamonddiamond crystalscrystals absorptioabsorptionn spectraspectra shoshoww broadbroad bandsbands aroundaround 430430 nm,nm, werewere ofof goodgood crystallinitycrystallinity andand highhigh quality.quality. I.S1.5.. 610610 nmnm (ordinary(ordinary ray)ray) andand a sharpsharp peakpeak atat 683683 nm.nm. ChemicalChemical analysesanalyses showshow thesthesee emeraldsemeralds havehave a highhigh CCrr GemGem newsnews fromfrom TucsonTucson 1997.1997. contentcontent (0.6-1.3(0.6-1.3 wt%)wt%) togethetogetherr withwith highhigh MgOMgO andand NapNa20 contentscontents.. TheThe aboveabove characteristicscharacteristics andand thethe constantconstant M.L.M.L. JOHNSONJOHNSON ANDAND J.I.J.I. KOIVULA.KOIVULA. Gems && Gemology, Gemology, 33(1), 33(1) , propertiesproperties ofof SandawanaSandawana emeraldsemeralds areare distinctive.distinctive. J.JJ.J.. 1997,60-70.1997, 60-70. A greengreen berylberyl hadhad a cabochoncabochon AustraliaAustraliann opalopal sesett CONCILIUM 4/0ECUMENISMEand withiwithinn thethe culetculet area,area, givinggiving riserise toto a curiouscurious effeceffectt ttoo ththee beryl.beryl. WhenWhen viewedviewed faceface up,up, thethe play-of-colourplay-of-colour frofromm thethe GemologieGemologie Aktuell.Aktuell. opalopal appearedappeared throughoutthroughout thethe stone.stone. OtherOther suchsuch stonesstones werewere onon exhibitionexhibition includingincluding amethyst,amethyst, aquamarinaquamarinee anandd H.H. BANK,BANK, U.U. HENNHENN ANDAND c.c.C.C. MILISENDA.MILISENDA. Gemmologie. goldengolden beryls.beryls. GilsonGilson syntheticsynthetic opalopal chipschips havhavee beebeenn setset iinn Zeitschrift derder Deutschen Deutschen Gemmologischen Gemmologischen Gesel/schaft, Gesellschaft, glassglas s toto formform briolettes,briolettes, heartshearts andand spheresspheres.. J.JJ.J.. 46(2),1997,63-70.46(2), 1997, 63-70. SomeSome tanzanitetanzanite 'synthetics''synthetics' onon thethe marketmarket werewere foundfound notnot be truetrue syntheticssynthetics butbut imitations;imitations; inin particpartic StructuralStructural analysisanalysis onon fluxflux growngrown emeraldemerald ularular,, polysilicatepolysilicate whichwhich wawass rejectedrejected asas realreal syntheticsynthetic crystals.crystals. tanzanitetanzanite.. A transparenttransparent facetedfaceted redred stonestone waswas foundfound toto J.-S.J.-S. LEE,LEE, P.-L.R-L. LEELEE ANDAND S.-c.S.-C. Yu.YU. Journal of of the the GeologicalGeological bebe a naturalnatural corundumcorundum overgrownovergrown byby syntheticsynthetic rubyruby Society of of China China [Taiwan], [Taiwan], 38(3), 38(3) 1995,273-85., 1995,273-85 . resultinresultingg inin a smallsmall layerlayer ooff dust-likedust-like mineraminerall inclusionsinclusions concentrateconcentratedd inin a thithinn layerlayer jusjustt underneathunderneath thethe rim.rim. CrystalsCrystals ofof syntheticsynthetic emeraldemerald growngrown bbyy a V220s-PbO05-PbO Recently an increasing number of hydrothermally 130 Recently an increasing number of hydrothermally fluxflux hadhad thethe compositioncomposition SiO,Si02 66.31,66.31, BeBeOO 13.70,13.70, A1AI,Ol203 130 produceproducedd syntheticsynthetic alexandritesalexandrites fromfrom Novosibirsk,Novosibirsk, 19.42,19.42, CrPlCr2Os 0.70,0.70, V,OsV205 0.040.04 = 100.17100.17 givingivingg ththee formulaformula Russia,Russia, havehave appearedappeared onon thethe market.market. TheirTheir mostmost AI,.o4Cro.osBe,.9sSis.9s0,8;Al204Cr005Be295Si595O18; theirtheir structurestructure wawass refinerefinedd ttoo diagnosticdiagnostic featuresfeatures areare distinctdistinct swirl-likeswirl-like growthgrowth RRL5 1.5%% (a 9.203,9.203, S;;ç 9.1729.172 A,Â, spacespace groupgroup ?6/mcc,P6/mcc, DDealecalc 3 inhomogeneitiesinhomogeneities,, sometimessometimes visiblvisiblee underunder a lOxlOx lenslens butbut 2.662.6688 g/g/cm cml)).. TheThe partiapartiall substitutionsubstitution ooff ththee excessexcess obviousobvious underunder a microscope.microscope. TheseThese syntheticsynthetic alexanalexan octahedraloctahedral cationscations (AI(Al andand Cr)Cr) forfor ththee tetrahedratetrahedrall BBee anandd dritesdrites areare producedproduced inin Novosibirsk.Novosibirsk. E.SE.5.. SiSi producedproduced a highlyhighly distorteddistorted Be04 tetrahedron,tetrahedron, confirmedconfirmed byby bond-anglebond-angle variancevariance andand NMNMRR spectrum.spectrum. TheThe applicationapplication andand propertiesproperties ofof Monocrystal.Monocrystal. TheThe substitutionsubstitution alsoalso involvesinvolves thethe incorporationincorporation ofof minorminor V atomsatoms asas impuritiesimpurities inin thethe channelschannels ofof thethe berylberyl strucstruc P.RRR. DEDE HEUS.HEUS. Industrial DiamondDiamond Review, Review, 57(572), 57(572) 1/97,, 1/97 , tureture:: differencedifference FourierFourier analysisanalysis showedshowed V ttoo bbee locatedlocated aatt 15-18,415-18,4 diagrams,diagrams, 2 photographs,photographs, bibl.bibl. (0,0,0.2901)(0,0,0.2901) andand (0,0,0.2909).(0,0,0.2909). TheThe centrecentre ooff thesthesee twotwo UnlikeUnlike naturalnatural diamondsdiamonds wherewhere slowslow crystalcrystal growthgrowth positionspositions isis (0,0,'/4)(0,0,1A) whichwhich isis thethe 2a2a sitsitee foforr alkalalkalii cationcationss iinn hahass concentratedconcentrated thethe nitrogenitrogenn atomsatoms inin flatflat layerslayers hydroushydrous alkali-richalkali-rich beryl.beryl. TheThe doubletdoublet configurationconfiguration forfor V (platelets),(platelets), inin a syntheticsynthetic diamonddiamond thethe growthgrowth isis rapidrapid inin thethe syntheticsynthetic emeraldemerald isis attributableattributable ttoo ththee high-T withwith ththee resultresult thatthat therethere areare hardlyhardly anyany nitrogennitrogen growthgrowth effecteffect ofof thesethese crystals.crystals. R.A.HRA.H.. crystalscrystals withinwithin thethe lattice;lattice; insteadinstead theythey areare randomlyrandomly distributeddistributed throughoutthroughout ththee lattice,lattice, gIvmggiving thethe MonocrystaMonocrystall itsits typicaltypical goldengolden colour.colour. TheseThese crystalscrystals YttriuYttriumm aluminiumaluminium perovskite.perovskite. displaydisplay exceptionalexceptional thermalthermal conductivityconductivity andand veryvery lowlow T.T. LINTON.LINTON. Australian Gemmologist, Gemmologist, 19(10), 19(10) 1997,419-20,3, 1997, 419-20 , 3 levellevel ofof internalinternal stressstress makingmaking themthem mostmost suitablesuitable forfor illus.illus. inin colour.colour. industrialindustrial applications,applications, whicwhichh cancan varyvary fromfrom dressingdressing ooff grindingrindingg wheels,wheels, machiningmachining ofof non-ferrousnon-ferrous metalsmetals (such(such PinkPink andand orangeorange facetedfaceted stones,stones, marketedmarketed inin thethe USAUSA asas asas aluminiumaluminium disksdisks forfor ththee computercomputer industry),industry), yttriumyttrium aluminiumaluminium perovskiteperovskite oror YAP,YAP, andand manufacturemanufacturedd inin machininmachiningg hardhard andand softsoft contactcontact lenses,lenses, toto thethe millingmilling ooff RussiaRussia byby thethe crystalcrystal pullingpulling processprocess,, werweree foundfound ttoo havhavee itemitemss ofof jewellerjewelleryy mademade ofof 2222 ctct gold.gold. E.SE.5.. propertiesproperties ofof hardness,hardness, SGSG andand RI,RI, whicwhichh diddid nonott matcmatchh thosethose ofof perovskiteperovskite andand areare thereforetherefore a simulansimulantt ooff thathatt mineralmineral.. TheThe pinkpink stonesstones havehave a highhigh refractivrefractivee indexindex ooff GrowthGrowth mechanismmechanism ofof flatteneflattenedd diamonddiamond 1.85,1.85, andand a dispersiondispersion nearnear thatthat ofof diamonddiamond.. WhilWhilee thesthesee crystals synthesized by chemical vapor crystals synthesized by chemical vapor stonesstones maymay superficiallysuperficially resembleresemble pinpinkk ArgylArgylee diamond,diamond, deposition.deposition. theitheirr lowerlower RIRI andand strikingstriking rarerare earthearth absorptioabsorptionn spectrspectraa K.K. HIRABAYASHIHIRABAYASHI ANDAND YY.. HIROSE.HiROSE. Journal of of Crystal Crystal Growth, Growth, shouldshould bebe sufficientsufficient toto identifyidentify thisthis newnew man-mademan-made product.product. 142,1994,140-6.142,1994,140-6. P.G.RP.G.R.. J./. Gemm., 1998,26,2,126-131 1998,26,2,126-131 Diamants:Diamants: lala synthesesynthèse aa uneune histoire.histoire. thesethese areare notnot alwaysalways veryvery usefuluseful forfor gemstonegemstone explorationexploration asas thethe resolutionresolution isis notno t finefine enough.enough. MoreMore recentlyrecently D.D. SIRAKIAN.SIRAKIAN. RevueRevue dede Gemmologie,Gemmologie, 131,131, 19971997,6-10., 6-10. ground-penetratingground-penetrating radarradar (Georadar)(Georadar) hashas beenbeen usedused foforr ContinuationContinuation ofof aa historyhistory ofof diamonddiamond synthesis:synthesis: ththee thethe explorationexploration ofof gemstonesgemstones usingusing radiowavesradiowaves toto studiesstudies ofof Hannay,Hannay, Moissan,Moissan, ParsonsParsons andand laterlater workersworkers measuremeasure thethe contrastcontrast inin electroconductivity,electroconductivity, producingproducing areare described.described. M.O'D.M.O'D. imagesimages similarsimilar inin appearanceappearance toto seismicseismic data.data. TheThe mainmain advantagesadvantages areare thatthat GeoradarGeoradar cancan definedefine subsurfacesubsurface A two-stagetwo-stage methodmethod forfor growinggrowing largelarge singlesingle featuresfeatures asas smallsmall asas 0.250.25 m,m, e.g.e.g . smallsmall pockets,pockets, andand isi s crystalscrystals ofof diamonddiamond withwith highhigh quality.quality. particularlyparticularly goodgood forfor mappingmapping shallowshallow subsurfacesubsurface deposits;deposits; thethe datadata cancan alsoalso givegive three-dimensionalthree-dimensional imagesimages WEIWEI LI,LI , H.H . KAGIKAGI ANDAND M.M . WWAKATSUKIAKATSUKI. . JournalJournal ofof CrystalCrystal andand isis cheapercheaper thanthan mostmost ofof thethe otherother methods.methods . Growth,Growth, 160,1996,78-86,7160,1996, 78-86, 7 figs.figs . TheThe authorauthor explainsexplains thethe rollroll ofof plateplate tectonicstectonics withwith A novelnovel methodmethod toto growgrow high-qualityhigh-quality largelarge diamonddiamond regardregard toto rockrock typestypes andand thereforetherefore wherewhere variousvarious crystalscrystals withwith aa largelarge netnet growthgrowth raterate hashas beenbeen developeddeveloped gemstonesgemstones areare mostmost likelylikely toto bebe found.found. HeHe alsoalso givesgives forfor diamonddiamond synthesissynthesis atat highhigh temperaturetemperature andand highhigh detailsdetails ofof howhow andand whywhy allall thethe geophysicalgeophysical methodsmethods areare pressurepressure inin metallicmetallic solution.solution. TheThe growinggrowing spacespace isis used;used; thesethese areare summarisedsummarised inin aa tabletable relatingrelating theirtheir usefuluseful designeddesigned toto havehave aa recessrecess atat itsits lowerlower temperaturetemperature side,side, nessness forfor gemstonesgemstones explorationexploration andand forfor thethe developmentdevelopment andand thethe seedseed crystalcrystal isis locatedlocated atat thethe bottombottom ofof thethe recess.recess. ofof knownknown oreore bodies.bodies. J.JJ,J.. WhenWhen thethe recessrecess isis filledfilled byby thethe first-stagefirst-stage growthgrowth ooff diamonddiamond fromfrom thethe seed,seed, itsits toptop surfacesurface servesserves asa sa a large large seedseed forfor thethe second-stagesecond-stage growth.growth. IfIf thethe sizesize ofof thethe recessrecess ReflexionsRéflexions sursur desdes techniquestechniques lapidaireslapidaires isis selectedselected appropriately,appropriately, thethe perfectionperfection andand qualityquality ofof thethe mogholes.mogholes. secondsecond-stag-stage e areare veryvery high.high. TheThe growthgrowth raterate isis smallsmall foforr E.E. GONTHIER.GONTHIER. Revue dede Gemmologie,Gemmologie, 131,131, 19971997,25-7., 25-7. thethe first-stagefirst-stage growthgrowth inin thethe recess,recess, butbut becomes.largerbecomes larger forfor Lapidary work during the Mogul period is described thethe second-stagesecond-stage growth.growth. TheThe diffusiondiffusion fieldfield aroundaround a Lapidary work during the Mogul period is described and some details of settings are also given. M.O'D. growthgrowth crystalcrystal isis numericallynumerically simulated,simulated, satisfactorilysatisfactorily and some details of settings are also given. M.O'D. explainingexplaining thethe growthgrowth nature.nature. IS.I.S. ShortShort informationinformation aboutabout gemmologicalgemmological sciencescience andand practice.practice. TwoTwo syntheticsynthetic phenakitesphenakites andand theirtheir structurestructure V.V.V.V . INDUTNYINDUTNY ANDAND L.r.L.I. VISHNEVSKA.VISHNEVSKA. PreciousPrecious andand analysis.analysis. Decorative Stones,Stones, 1(7),1(7), 1997,1997, 7-14,7-14, illus.illus. inin colour,colour, inin 131 Ukrainian.Ukrainian. 131 S.-c.S.-C. YuYu ANDAND J.-S.J.-S . LEE.LEE. JournalJournal ofof thethe GeologicalGeological SocietySociety of ChinaChina [Taiwan],[Taiwan], 38(4), 38(4) ,1995, 1995 ,383-96. 383-96 . CommentsComments onon thethe establishmentestablishment andand publicationpublication ooff thethe rightsrights ofof jewelleryjewellery manufacturersmanufacturers byby thethe useuse ofof tradetrade TwoTwo flux-grownflux-grown phenakites,phenakites, oneone colourlesscolourless andand theth e andand otherother distinguishingdistinguishing marksmarks onon theirtheir products.products. otherother bluish-green,bluish-green, formedformed asas minorminor accessoriesaccessories inin aann ParticularParticular attentionattention isis paidpaid toto thethe amberamber recoveredrecovered fromfrom emeraldemerald growthgrowth experiment;experiment; bothboth phenakitesphenakites areare closeclose toto thethe depositsdeposits ofof thethe statestate enterpriseenterprise 'Ukrburshtin'.'Ukrburshtin'. M.O'D.M.O'D . thethe idealideal compositioncomposition ofof Be,Si0Be2Si044 butbut thethe colouredcoloured ononee containscontains 0.30.3 wt%wt% ofof VV impurities.impurities. BothBoth areare trigonal,trigonal, spacespace groupgroup R3;R3; thethe colourlesscolourless (bluish-green)(bluish-green) crystalscrystals havehave AA newnew viewview onon thethe mechanismmechanism ofof diamonddiamond aa 12.46612.466 (12.472),(12.472) , cc 8.2448.244 (8.253)(8.253) A;À; structuralstructural refinementsrefinements polishing.polishing. gavegave finalfinal RR factorsfactors ofof 1.811.81 (1.49)%.(1.49)% . InIn thethe bluish-greenbluish-green F.M.F.M . VANVAN BOUWELEN,BOUWELEN, L.M.L.M. BROWNBROWN ANDAND J.E.J.E. FIELD.FIELD . IndustrialIndustrial phenakitephenakite twotwo VV atomatom positionspositions areare recognized;recognized; thesethese areare DiamondDiamond Review, 57(572),57(572), 1/97,1/97, 21-5,21-5, 44 illus.illus. inin blackblack- atat interstitialinterstitial positionspositions ratherrather thanthan substitutingsubstituting forfor BeBe oorr and-white,and-white, 22 tables.tables. Si.Si. ItIt isis inferredinferred thatthat thethe greengreen colourcolour isis duedue toto thethe crystalcrystal fieldfield splittingsplitting ofof thethe dd electronelectron orbitalsorbitals ofof thethe interstitialinterstitial A conceptconcept isis proposedproposed forfor thethe developmentdevelopment ofof a vanadium.vanadium. RA.H.R.A.H. modelmodel toto describedescribe thethe highlyhighly anisotropicanisotropic behaviourbehaviour ooff diamonddiamond duringduring frictionalfrictional contactcontact andand polishing.polishing. ThThee useuse ofof ScanningScanning ProbeProbe MicroscopyMicroscopy techniquestechniques havehave confirmedconfirmed thatthat afterafter polishingpolishing inin thethe hardhard octahedraloctahedral Techniques and ApplicationS' {111){111} planeplane thethe diamond'sdiamond's surfacesurface showsshows thatthat fracturefracture andand chippingchipping mechanismsmechanisms areare involvedinvolved inin materialmaterial removal.removal. However,However, inin thethe softsoft {l00){100} cubiccubic direction,direction, a ApplicationsApplications ofof geophysicsgeophysics inin gemstonegemstone formform ofof nano-groovingnano-grooving appearsappears toto taketake placeplace whichwhich exploration.exploration. producesproduces amorphousamorphous andand graphiticgraphitic debrisdebris (often(often F.A.F.A. COOK.COOK. GemsGems && Gemology,Gemology, 33(1),1997,4-23,1133(1), 1997,4-23,11 illus.illus. inin referredreferred toto asas 'black'black powder').powder'). colour.colour. TheThe removalremoval ofof materialmaterial whilewhile polishingpolishing inin thethe softsoft GeophysicsGeophysics hashas playedplayed aa vitalvital rolerole inin thethe explorationexploration directiondirection maymay bebe causedcaused byby aa mechanicallymechanically inducedinduced ofof mineralsminerals andand hydrocarbonshydrocarbons forfor manymany years,years, butbut thisthis hashas degradationdegradation ofof diamonddiamond byby bondbond bending.bending. InIn thethe hardhard notnot beenbeen thethe casecase forfor gemstones,gemstones, wherewhere explorationexploration direction,direction, thethe distortiondistortion ofof thethe crystalcrystal byby bondbond bendingbending isis techniquestechniques havehave remainedremained relativelyrelatively simple.simple. TheThe mostmost relativelyrelatively small,small, andand doesdoes notnot allowallow forfor aa weakeningweakening ofof thethe commoncommon geophysicalgeophysical techniquestechniques includeinclude thethe useuse ofo f structure.structure. FurtherFurther theoreticaltheoretical workwork isis neededneeded toto studystudy thethe gravity,gravity, magnetism,magnetism, seismicseismic reflectionreflection profiling,profiling, etc.,etc., butbut realisticrealistic valuevalue ofof thisthis concept.concept. P.G.RP.G.R. AbstractsAbstracts -- TechniquesTechniques and and Applications Applications BOOBOOKK REVIEW REVIEWSS DiscoveDiscoverr opalsopals.. possiblpossiblee .iiss availablavailablee ttoo ththee readereaderr whwhoo mamayy finfindd ththee SS.. ARACICARACIC,, 19961996.. ThThee AuthoAuthorr [P.O[P.O.. BoBoxx 143143,, LightninLightningg smallesmallerr localllocallyy publishepublishedd historiehistoriess harhardd ttoo find.. RidgeRidge,, NSNSWW 28342834,, Australia],. pppp 352352,, illusillus.. iinn colourcolour,, SimilaSimilarr treatmenttreatment,, iiff leslesss extensiveextensive,, iiss givegiven ttoo WhitWhitee hardcover.. $A100.00$AI00.00. ISBISBNN 0 959589595833 0101 77.. Cliffs,, TintenbaTintenbarr (onc(oncee mormoree ththee opaopall frofromm thithiss areareaa iiss OOff course,, aann illustrateillustratedd boobookk oonn opaopall cacann hardlhardlyy faifaill statestatedd ttoo be unstablunstablee thougthoughh materiamateriall witwithh a jet-blacjet-blackk ttoo bbee attractivattractivee anandd interestinginteresting.. TherTheree havhavee beebeenn many bodbodyy anandd plaplayy ooff coloucolourr iiss attractive), anandd ttoo otheotherr smallesmallerr bookbookss oonn opaopall iinn ththee laslastt few years years,, mosmostt ooff thethemm mineminess iinn NeNeww SoutSouthh WalesWales.. OpaOpall frofromm otheotherr AustraliaAustraliann publishepublishedd iinn Australia:: as a generagenerall survesurveyy ooff AustraliaAustraliann states iis describedescribedd iinn a similasimilarr wawayy ssoo thathatt thertheree iiss littllittlee leftleft opalopal,, ititss mininminingg anandd geology, ththee presenpresentt boobookk (publishe(publishedd unsaid.. IInn SoutSouthh Australia, CoobeCooberr Pedy anandd AndamookAndamookaa aass a limitelimitedd editioedition ooff 15015000 copiescopies)) iiss ththee besbestt I havhavee seeseenn taktakee pridpridee ooff placplacee anandd thertheree araree extensiveextensive descriptionsdescriptions ooff anandd shoulshouldd persispersistt iinn availabilitavailabilityy (perhap(perhapss aass a generagenerall QueenslanQueenslandd bouldeboulderr anandd nunutt opalopal.. PerhapPerhapss leslesss welwelll known is the opal found in the gold-fields of Western ratheratherr thathann a limitelimitedd print-run), finallfinallyy establishinestablishingg itselitselff known is the opal found in the gold-fields of Western aass aann accepteacceptedd classiclassicc alonalongg witwithh ththee bookbookss ooff WollastoWollastonn Australia:: qualitqualityy iiss reportereportedd ttoo bbee highighh anandd sspecimenpecimenss anandd MurphyMurphy.. havhavee a blacblackk backgrounbackgroundd bubutt depositdepositss werweree nonot beinbeingg workeworkedd aatt ththee timtimee ooff writingwriting.. ThThee textextt dealdealss witwithh ththee majomajorr fieldfieldss ooff NeNeww SouthSouth WalesWales,, SoutSouthh AustraliaAustralia,, QueenslanQueenslandd anandd WesternWestern ThiThiss iiss nonott onlonlyy aann authoritativauthoritativee studstudyy ooff AustraliaAustraliann AustraliAustraliaa anandd manmanyy ooff ththee individuaindividuall mineminess iinn thesethese statesstates opaopall witwithh aann amazinamazingg amounamountt ooff informatioinformationn bubutt a boobookk araree describedescribedd iinn somsomee detaildetail.. BuButt beforbeforee ththee survesurveyy beginbeginss thathatt cacann bbee reareadd aatt ananyy timtimee witwithh ththee greatesgreatestt pleasurepleasure.. II thertheree iiss considerablconsiderablee coveragcoveragee ooff surveyingsurveying foforr likellikelyy aamm nonott sursuree thathatt ththee bindinbindingg wilwilll stanstandd uupp to ververyy heavheavyy depositdepositss ooff opalopal,, diviningdivining,, pegginpeggingg anandd workinworkingg claimsclaims,, usagusagee anandd iitt woulwouldd bbee churlischurlishh ttoo expecexpectt a comprehencomprehensivsivee processinprocessingg ofof ththee recovererecoveredd rougroughh opal: thertheree areare alsoalso pen- lislist ofof referencereferencess - thithiss iiss nonott ththee aimaim ooff ththee author.. IInn ananyy portraitportraitss ofof celebratedcelebrated miners andand charactercharacterss ooff ththee opalopal cascasee thetheyy appearappear inin otherother studiesstudies andand ththereree iiss a boobookk 132132 fields.. TheThe nexnextt 4400 pagepagess dealdeal witwithh opalopal asas a mineralmineral,, ititss devotedevotedd ttoo opaopall bibliographbibliographyy [De[De Boer, 1995].1995]. Aracic's formation,formation, thethe typetypess ofof opaopall andand ththee veryvery largelarge numbernumber ooff beautifulbeautiful boobookk deservesdeserves toto standstand withwith thethe grgreateseatestt ofof opalopal coloucolourr patternpatternss recognizedrecognized bbyy minerminerss andand dealers.dealers. SomeSome studistudieess iiff itit isis nonott thathatt samesame studystudy itself.. M.O'DM.O'D.. famoufamouss stonesstones areare illustrateillustratedd andand describeddescribed andand aann attemptattempt iiss mademade toto equate opalopal typetypess withwith theitheirr fieldsfields ooff TheThe F.F. JohJohnn BarloBarloww mineraminerall collection. origin.origin. MatrixMatrix opalopal isis describeddescribed andand a googoodd accountaccount ooff F.F. JJOHOHNN BARLOW,BARLOW, 1996.1996. SancoSanco PublishingPublishing [PO[PO Box 177177,, treated opal matrix will be most interesting to readers in treated opal matrix will be most interesting to readers in AppletoAppletonn WIWI 54912-0177],54912-0177], Appleton,Appleton, Wisconsin.Wisconsin. Europe and countries outside Australia, where this Europe and countries outside Australia, where this pp408pp 408, ilIusillus. inin colourcolour,, hardcoverhardcover.. US$208.68US$208 .68. interesting, deceptive and beautiful material is less often interesting, deceptive and beautiful material is less often ISBNISBN 0 96535109653510 00 9.9 . encountered.encountered. SyntheticSynthetic opaopal isis alsoalso describeddescribed alongalong withwith ththee probleproblemm ofof cracking, opalopal pseudomorphouspseudomorphous afterafter TheThe F.F. JJohohnn BarlowBarlow mineralmineral collectioncollection hashas beenbeen knownknown fossils, ththee firstfirst discoverydiscovery ofof opal,opal, opalopal cuttingcutting anandd forfor years, nonott only by mineralogistsmineralogists andand collectorscollectors bubutt alsoalso polipolishingshing,, automaticautomatic cutting, sellingselling valuevalue andand investinvest bbyy many whowho hahavve vvisiteisitedd museumsmuseums toto whicwhichh items havehave ment.ment. WorldWorld marketsmarkets andand superstitionssuperstitions areare coveredcovered inin thethe travelledtravelled fromfrom ththee collectioncollection toto findfind theirtheir finalfinal home lastlast partpart ofof thethe generalgeneral sectionsection beforebefore thethe areaarea coveragecoverage through thethe generositygenerosity ofof thethe collectioncollection''ss founder.. ItIt is oneone beginsbegins.. ofof thethe finestfinest cabinetscabinets ofof mineralsminerals everever asassemblesembledd anandd includesincludes manymany gemgem mineralsminerals inin theirtheir mostmost beautifulbeautiful OfOf thethe NewNew SouthSouth WalesWales opalopal fields,fields, LightningLightning RidgeRidge crystalcrystal formsforms andand colours:colours: thethe aimaim hashas beenbeen toto obtainobtain ththee takestakes pridepride ofof placeplace andand aboutabout fiftyfifty pagespages areare devoteddevoted ttoo bestbest specimensspecimens ofof theirtheir kindkind andand nono doubtdoubt frequentfrequent it.it. A mapmap givesgives itsits locationlocation withinwithin thethe statestate andand ththee upgradingupgrading hashas takentaken place.place. coveragecoverage ofof thethe fieldfield wouldwould serveserve asas anan industrialindustrial anandd socialsocial historyhistory asas wellwell asas a surveysurvey ofof thethe economicseconomics ofof opalopal The firstfirst ofof thethe sixsix mainmain sectionssections ofof thee bookbook oopenpenss with a short biography of John Barlow and then miningmining andand itsits effects.effects. AsAs itit happens, colourcolour photographsphotographs with a short biography of John Barlow and then commences the mineral descriptions with the 'classics', of mostmost LightningLightning RidgeRidge opalopal specimensspecimens areare foundfound chieflychiefly commences the mineral descriptions with the 'classics', this section being followed by fifty pages of gem crystal inin thethe precedingpreceding sectionssections wherewhere exceptionalexceptional opalsopals araree this section being followed by fifty pages of gem crystal species: here, tourmaline has a section to itself, followed described. NonethelessNonetheless a veryvery largelarge coveragecoverage ofof thethe opals species: here, tourmaline has a section to itself, followed by a survey of beryl and the gem minerals to be found in is herehere andand a secondsecond andand latlateer mapsmaps give,give, inin closeclose detaildetail by a survey of beryl and the gem minerals to be found in andand toto scale,scale, allall thethe workingworking depositsdeposits thatthat cancan bebe saidsaid ttoo pegmatites.pegmatites. GemstonesGemstones withwith otherother rarerare andand importantimportant bebe inin thethe LightningLightning RidgeRidge aarearea.. UsefulUseful diagramsdiagrams showshow thethe mineralsminerals completecomplete thisthis thirdthird section.section. stratastrata inin whichwhich opalopal cancan bebe ffounoundd andand therethere areare manymany PParartt fourfour describesdescribes a suitesuite ofof nativenative eelementlements whichwhich picturespictures ofof mines,mines, ofof theirtheir dumpsdumps andand ofof claimclaim maps.maps. includinclude gold,gold, platinumplatinum andand goldgold andand silver-bearingsilver-bearing DetailsDetails ofof somesome famousfamous casescases concerningconcerning miners'miners' rightsrights minerals.minerals. PartPart fivefive coverscovers mineralsminerals fromfrom especiallyespecially areare givengiven soso thatthat asas completecomplete aa LightningLightning RidgeRidge historyhistory asas notablenotable locations,locations, includingincluding Africa,Africa, Mexico,Mexico, thethe majormajor redred J.J . Gemm., 1998,26 1998, 26,, 2 2,, 132- 132-134134 beryberyll sitesite inin ththee WahWah WahWah mountainsmountains ofof UtaUtahh andand others.others. inin papers!papers! TheThe authorsauthors andand artistartist (Peter(Peter LI. Russell)Russell) areare toto bebe TheThe collectorcollector givesgives aann outlinoutlinee ofof hishis ownown philosophphilosophyy ooff congratulatedcongratulated onon a finefine andand veryvery reasonablyreasonably pricedpriced workwork mineralmineral collectingcollecting iinn a concludingconcluding chapter.chapter. whichwhich willwill havehave considerableconsiderable relevancerelevance forfor gemmologists.gemmologists. OnceOnce thethe descriptivedescriptive partpart ofof thethe boobookk isis openedopened thethe M.O'D.M.O'D. readerreader findsfinds magnificentmagnificent colourcolour picturespictures onon eacheach opening,opening, with some pages accommodating two or even three with some pages accommodating two or even three A brilliantbrilliant history:history: jeweljewelss atat Sotheby's.Sotheby's. photographsphotographs.. AlAlll areare accompanieaccompaniedd byby fullfull detailsdetails ofof thethe mineralmineral depicted,depicted, notenotess onon thethe size,size, modemode ofof occurrence,occurrence, 1997.1997. Sotheby's,Sotheby's, London.London. Unpaginated,Unpaginated, ilIus.illus. inin colour,colour, chemicalchemical composition,composition, worldworld rankingranking wherwheree applicableapplicable softcover.softcover. andand fullfull crystalcrystal morphology.morphology. ThThee photographphotographss ofof gegemm PresentationPresentation ofof ththee workwork ofof Sotheby'sSotheby's jewelleryjewellery mineralsminerals occupyoccupy quitequite a lotlot ofof thethe bookbook andand intendingintending departmentsdepartments withwith notenotess ofof illustrationsillustrations fromfrom majormajor salessales.. readersreaders shouldshould savesave upup toto buybuy itit -—yes, yes, itit is is expensive expensive but but ShortShort biographiesbiographies areare givengiven andand a sectionsection onon worldworld recordrecord worthworth everyevery cent.cent. I havehave seenseen nono comparablecomparable boobookk iinn pricesprices isis arrangedarranged byby gemstone.gemstone. ThisThis isis a beautifullybeautifully thirtythirty yearsyears'' familiarityfamiliarity withwith thethe world'world'ss mineralogicalmineralogical producedproduced celebrationcelebration bookletbooklet whichwhich willwill becomebecome aa literature.literature. M.O'DM.O'D.. collector'scollector's item.item. M.O'DM.O'D.. EncyclopaediaEncyclopaedia ofof mineralmineral names.names. GoldGold imim HerzenHerzen Europa:Europa: Gewinnung..Gewinnung, W.H.W.H. BLACKBURNBLACKBURN ANANDD w.H.W.H. DENNEN,DENNEN, 1997.1997. MineralogicalMineralogical Bearbeitung..Bearbeitung, VerwendungVerwendung.. AufsatzeAufsätze undund Katalog.Katalog. AssociationAssociation ofof Canada,Canada, Ottawa.Ottawa. [Mineralogical[Mineralogical 1996.1996. Bergbau-undBergbau-und IndustriemuseumIndustriemuseum Ostbayem,Ostbayern, AssociationAssociation ofof Canada,Canada, specialspecial publicatiopublicationn no.no. 1.1.]] Kiimmersbruck.Kümmersbruck. pppp294 294,, illus.illus. inin colour,colour, softcover.softcover. pppp 360,360, artworartworkk iinn black-and-white,black-and-white, hardback.hardback. DM44DM44 includingincluding postagepostage andand packing.packing. US$40.00US$40.00.. ISBNISBN 0 921294921294 4545 XX.. ISBNISBN 33 925690925690 3333 6.6. (The(The MuseumMuseum is is atat Schloss Schloss Theuem, Theuern , NowNow thathatt ththee numbenumberr ofof validvalid mineralmineral speciesspecies PortnerstrassePortnerstrasse 1.1,9224 922455 Kiimmersbruck,Kümmersbruck, Germany.)Germany.) approachesapproaches 38003800 thethe appearancappearancee ofof anan encyclopaediaencyclopaedia iiss AlthoughAlthough thethe bookbook includesincludes a cataloguecatalogue ofof aann timely.timely. UnlikeUnlike previoupreviouss attempts,attempts, allall mormoree oror lessless goodgood forfor exhibitionexhibition ofof goldgold andand gold-mininggold-mining artefactsartefacts inin placeplace aatt theirtheir time,time, thisthis oneone isis notnot overloadedoverloaded withwith discredited,discredited, tradetrade thethe Bergbau-Bergbau- undund IndustriemuseumIndustriemuseum OstbayernOstbayern duringduring andand fancifulfanciful namenamess bubutt isis confinedconfined onlyonly ttoo speciesspecies 1996,1996, thethe cataloguecatalogue itselfitself occupiesoccupies onlyonly a relativelyrelatively smallsmall accreditedaccredited byby publicationpublication inin standardstandard mineralogicalmineralogical portionportion ofof thethe completecomplete text,text, beingbeing placedplaced atat thethe backback ooff journalsjournals,, somesome ofof thethe latestlatest citationscitations beingbeing publishedpublished inin 1997.1997 . thethe book,book, thethe remainderremainder ofof whichwhich givesgives anan authoritativeauthoritative AnnualAnnual listslists ofof additionsadditions areare scheduledscheduled toto bbee carriedcarried inin thethe account,account, currentcurrent andand historical,historical, ofof goldgold andand goldgold miningmining inin 133133 Canadian mineralogist, mineralogist, the thfirste firs oft theseof thes toe appearto appea inr thein the BavariaBavaria andand inin a fewfew neighbouringneighbouring areas.areas. SinceSince manymany AugusAugustt 19981998 issueissue (vol.(vol. 3636 partpart 4).4). InIn thisthis wawayy ththee monomono gemmologistsgemmologists areare alsoalso interestedinterested inin preciousprecious metals,metals, theirtheir graphgraph cancan enjoyenjoy a continuingcontinuing usefulnessusefulness untiuntill thethe numbernumber ofof recoveryrecovery andand application,application, thethe bookbook shouldshould arousearouse additionsadditions makemakess a freshfresh singlesingle volumevolume necessarynecessary.. considerableconsiderable interest.interest. A numbernumber ofof authorsauthors contributecontribute IntroductoryIntroductory mattermatter introducesintroduces thethe readereaderr ttoo thethe chapterschapters onon thethe historhistoryy ofof BavarianBavarian goldgold deposits,deposits, oonn derivationderivation ofof wordswords fromfrom theirtheir roots,roots, whichwhich mamayy lielie inin aa similarsimilar depositsdeposits inin Bohemia,Bohemia, onon goldgold inin historyhistory andand art,art, onon Celtic money found in the Oberpfalz and considerably varietyvariety ofof languages,languages, notnot allall ofof themthem European.European. A shortshort Celtic money found in the Oberpfalz and considerably historyhistory andand summarysummary ofof howhow mineralsminerals areare namednamed explainsexplains more.more. TheThe cataloguecatalogue describesdescribes andand illustratesillustrates goldgold objects,objects, thethe variouvariouss classificationsclassifications ofof mineralsminerals usedused inin thethe past:past: thethe miningmining implementsimplements andand pagespages fromfrom books,books, withwith a highhigh quality of reproduction overall (dimensions are given LinneanLinnean systemsystem ofof groupingsgroupings waswas forfor a timetime attemptedattempted forfor quality of reproduction overall (dimensions are given mineralsminerals bubutt nevernever gogott farfar becausebecause techniquetechniquess ofof chemicalchemical wherewhere appropriate).appropriate). TheThe chapterschapters havehave theirtheir ownown listslists ooff analysisanalysis werewere insufficientlyinsufficiently refinedrefined untiluntil quitequite recentlyrecently.. referencesreferences whichwhich inin somesome casescases areare extensive:extensive: black-andblack-and- whitewhite photographsphotographs scatteredscattered amongamong thethe non-cataloguenon-catalogue TheThe speciesspecies areare listedlisted inin alphabeticalalphabetical orderorder witwithh eacheach portionportion ofof thethe textextt illustrateillustrate thethe diversediverse usesuses ofof goldgold andand entryentry carryingcarrying namename,, chemicalchemical composition,composition, crystalcrystal systemsystem somesome ofof thethe workingworking methodsmethods ofof formerformer times.times. M.O'D.M.O'D. andand spacespace groupgroup - somesome ofof thesethese characteristicscharacteristics areare queriedqueried inin thethe textextt whewhenn ambiguitieambiguitiess oror optionsoptions exist.exist. ThThee etymologyetymology ofof ththee namnamee isis givengiven nextnext withwith transliterationstransliterations MineralienMineralien FundstellenFundstellen inin derder TchechischenTchechischen undund fromfrom ArabicArabic,, Chinese,Chinese, Greek,Greek, Japanese,Japanese, PersianPersian oror CyrillicCyril1ic.. SlowakischenSlowakischen Republik.Republik. SpeciesSpecies entriesentries forfor personspersons (about(about 45%45% ofof thosethose cited)cited) carrycarry P.P. PAULISPAULIS ANDAND R.R . HAAKE,HAAKE, 1997.1997. BodeBode Verlag,Verlag, Haltem.Haltern. briebrieff biographicabiographicall informatioinformationn andand referralsreferrals toto biographicalbiographical [Oerter[Oerter PlittPütt 28,28, 0-45721D-45721 Haltem,Haltern, Germany.]Germany.] pppp 9696,, notesnotes publishepublishedd elsewhere.elsewhere. TheThe sourcesource ofof thethe originaloriginal studystudy illus.illus. iinn colour,colour, softcover.softcover. DM22.80DM22.80 (including(including postpost materiamateriall isis given,given, whenwhen knownknown andand whewhenn nonott alreadyalready andand packing).packing). ISBNISBN 3 925094925094 5151 22.. includedincluded inin thethe etymology.etymology. ReferencesReferences toto majormajor journaljournaJss araree MineralMineral locationslocations inin thethe CzechCzech andand SlovakianSlovakian givengiven forfor allall originaloriginal speciesspecies descriptions.descriptions. RepublicsRepublics areare described.described. OnOn mapsmaps ofof thethe twotwo countriescountries TheThe bookbook,, witwithh attractiveattractive artworkartwork,, isis veryvery easyeasy oonn thethe locationslocations areare marked,marked, carryingcarrying numbersnumbers whichwhich referrefer toto anan eyeeye andand a carefulcareful read-throughread-through failedfailed toto showshow uupp anyany accompanyingaccompanying listlist whichwhich thenthen providesprovides thethe readerreader witwithh a glaringglaring omissionsomissions oror inconsistenciesinconsistencies.. ThereThere isis a shortshort pagepage number.number. AAnn oddodd arrangementarrangement butbut bearingbearing languagelanguage thoughthough usefuusefull bibliographbibliographyy andand a listlist ofof journajournall abbreviaabbrevia difficultiesdifficulties inin mindmind oneone whichwhich worksworks fairlyfairly wellwell inin soso tionstions whichwhich isis handiehandierr thathann iitt maymay seemseem atat first:first: yoyouu cancan smallsmall a book.book. A moremore seriousserious desideratumdesideratum isis thethe absenceabsence nevernever findfind thethe precisprecisee titltitlee ofof a journajournall fromfrom abbreviationsabbreviations ofof a speciesspecies index,index, soso thatthat thethe searchersearcher forfor 'edelopal''edelopal' Book reviews reviews woulwouldd havehave toto knowknow ththee locallocal namnamee forfor thethe depositdeposit oror (as(as followedfollowed bbyy a discussiondiscussion ofof necklacenecklace typetypess anandd claspsclasps,, a I did)did) readread rightright throughthrough thethe texttext inin thethe hopehope ofof findingfinding glossaryglossary andand a bibliography.bibliography. WorkinWorkingg drawingsdrawings accomaccom something.something. panpanyy somesome ofof thethe photographsphotographs - theythey alwaysalways addadd ttoo thethe PreciousPrecious opalopal fromfrom ththee DubniDubnikk deposit,deposit, nownow inin picturpicturee - andand descriptionsdescriptions includeinclude provenancprovenancee wherewhere Slovakia,Slovakia, isis describeddescribed onon pagepage 86:86: a briefbrief sketchsketch ofof thethe appropriateappropriate asas wellwell asas detailsdetails ooff stylestyle,, metametall andand deposidepositt isis givengiven withwith a briefbrief descriptiondescription ofof itsits geology,geology, gemstones.gemstones. M.O'D.M.O'D. mineralogymineralogy andand history.history. ThisThis isis thethe depositdeposit sometimessometimes shownshown asas CervenicaCervenica onon specimenspecimen labelslabels andand littlelittle workwork DieDie MineralienMineralien undund FundstellenFundstellen vovonn Schweden.Schweden. appearappearss ttoo bbee goinggoing onon atat present.present. H.-J.H.-J. WILKE,WILKE, 1997.1997. ChristianChristian WeiseWeise VerlagVerlag,, Miinchen.München, Many'Many otherother importanimportantt mineraminerall sitessites areare describeddescribed andand pppp 200,200, illus.illus. inin colour,colour, hardcover.hardcover. DM80.00DM80.00 (including(including despitedespite thethe smalsmalll sizesize andand thethe lacklack ofof a speciesspecies index,index, thisthis isis postage).postage). ISBNISBN 3 921656921656 4141 9.9. a welcomewelcome bookbook andand includesincludes a goodgood currentcurrent bibliography.bibliography. M.O'D.M.O'D. ThoughThough specimensspecimens ofof gemgem qualityquality araree absentabsent fromfrom thethe mineralogymineralogy ofof Sweden,Sweden, manymany gemmologistsgemmologists araree mineralmineral TheThe beadbead jewellerjewelleryy book.book. collectorscollectors tootoo andand forfor moremore thanthan ononee reasoreasonn thithiss bookbook deservesdeserves a note.note. FourFour chemicalchemical elementelementss derivderivee theirtheir S.S. TOMALIN,TOMALIN, 1997.1997. DaviDavidd & Charles,Charles, NewtonNewton Abbot.Abbot, namesnames fromfrom YtterbyYtterby,, neanearr Stockholm,Stockholm, andand ththee U.ngbanLângban pppp 128,128, illus.illus. inin colour,colour, hardcoverhardcover.. £16.99.£16.99. areaarea isis oneone ofof thethe world'sworld's mostmost productiveproductive ofof individualindividual ISBNISBN 0 71537153 04650465 8.8. species.species. Furthermore,Furthermore, thisthis isis ththee onlyonly boobookk I havhavee seenseen inin WitWithh excellentexcellent photographphotographss byby MaggieMaggie CampbellCampbell whichwhich ththee firstfirst pagespages ofof textextt linklink locationlocation witwithh individualindividual PedersenPedersen andand atat soso reasonablreasonablee a priceprice thisthis bookbook wouldwould makemake mamapp sheetssheets ofof thethe country'scountry's geologicalgeological survey.survey. ThisThis a goodgood presentpresent forfor almostalmost anyone,anyone, letlet alonealone thethe manymany profesprofes featurefeature,, togethertogether withwith a particularlparticularlyy extensiveextensive sionalsional beadbead craftcraft workerworkerss andand ththee increasingincreasing numbernumber whowho bibliography,bibliography, providesprovides anan outstandingoutstanding exampleexample ooff howhow makemake theirtheir ownown jewellerjewelleryy atat homehome.. TheThe pointpoint mademade bbyy thethe suchsuch mineralogymineralogy shouldshould bbee arranged.arranged. TheThe sitessites,, arrangedarranged bookbook isis thathatt youyou cancan inin facfactt dodo thisthis,, andand notesnotes onon materialsmaterials inin fourfour geographicalgeographical sections,sections, areare fullfullyy describedescribedd andand andand techniquestechniques accompanyaccompany descriptionsdescriptions ofof classicclassic jewelleryjewellery eacheach hashas itsits ownown sketch-map.sketch-map. CollectorsCollectors ooff rarraree mineralsminerals forms.forms. ThisThis reviewer,reviewer, allall ofof whosewhose fingersfingers areare thumbs,thumbs, mightmight wilwilll bbee particularlparticularlyy interestedinterested inin thisthis excellentexcellent survesurveyy inin managmanagee oneone oror twtwoo ofof thethe ververyy simplestsimplest designsdesigns bubutt iiff whichwhich manymany speciesspecies areare beautifullybeautifully illustrateillustratedd iinn colour.colour. greategreaterr skillsskills werweree calledcalled for,for, thithiss woulwouldd bebe thethe firstfirst boobookk toto M.O'DM.O'D.. consult.consult. ItIt wouldwould bebe hardhard toto beat.beat. M.O'D.M.O'D. 134134 Zillertal.Zillertal. TheThe necklacenecklace fromfrom antiquityantiquity toto thethe present.present. DasDas TalTal derder GriindeGründe undund Kristalle,Kristalle, 1997.1997. pppp 100,100, illusiI1us.. inin A.A. TRIOSSITRIOSSI ANANDD D.D. MASCETII,MASCETTI, 1997.1997. ThamesThames andand Hudson,Hudson, colour,colour, softcover.softcover. DM48.9DM48.922 (includin(includingg postage).postage). London.London, pppp 224,224, illus.illus. inin colour,colour, hardcover.hardcover. £32.00.£32.00. [SBNISBN 3 921656921656 4040 O.0. [extraLapis nnoo 12.]12.] ISBNISBN 0 599599 0176701767 O.0. TheThe authorsauthors jointljointlyy havehave previouslpreviouslyy addedadded lustrelustre toto TheThe latestlatest monographicmonographic supplementsupplement ttoo ththee GermanGerman ththee literatureliterature ofof jewellerjewelleryy historhistoryy withwith Earrings (1990)(1990) andand journajournall Lapis (costed(costed outsideoutside thethe journajournall subscription)subscription) Bulgari (1996).(1996). TheirTheir accountaccount ofof thethe development,development, dealsdeals withwith anan areaarea ofof considerableconsiderable interesinterestt toto manufacture,manufacture, style,style, ususee andand significancesignificance ofof ththee necklacenecklace isis gemmologistsgemmologists andand mineralmineral collectors.collectors. WhilWhilee ththee ZillertalZillertal a well-producedwell-produced tributetribute ttoo oneone ofof thethe oldestoldest andand mostmost inin thethe AustrianAustrian AlpsAlps providesprovides ornamentalornamental andand sometimessometimes gem-quality dark-red garnet which is often faceted, there adaptableadaptable piecespieces ofof ornament.ornament. YoYouu cancan dodo anythinganything youyou gem-quality dark-red garnet which is often faceted, there are also fine sceptre crystals of rock crystal and amethyst, wanwantt withwith a necklacenecklace - makemake iitt yourself,yourself, givegive itit anyany are also fine sceptre crystals of rock crystal and amethyst, euhedraleuhedral crystalscrystals ofof amethyst,amethyst, citrinecitrine anandd smokysmoky quartz,quartz, magicamagicall oror medicalmedical propertiepropertiess thatthat seemseem appropriateappropriate atat epidote,epidote, greengreen grossular,grossular, orangeorange hessonitehessonite,, greengreen anyoneany one time,time, putput anyany stonesstones yoyouu wanwantt intointo it,it, changechange diopside,diopside, greengreen titanitetitanite (sphene),(sphene), colourlescolourlesss moonstonemoonstone thethemm (with(with oror withoutwithout tellingtelling anyone)anyone) andand upgradeupgrade themthem andand greengreen tourmaline.tourmaline. ChaptersChapters dealdeal witwithh ththee majormajor whenwhen moremore moneymoney isis atat handhand.. NecklacesNecklaces areare easilyeasily mademade mines and collecting areas, their mineralogy and geology, ttoo echoecho stylesstyles ofof dressdress andand withwith nono assistanceassistance fromfrom anyany mines and collecting areas, their mineralogy and geology, with gold and with the finding of garnet and its orna otheotherr ornament,ornament, telltell thosethose whowho looklook atat themthem whenwhen theythey with gold and with the finding of garnet and its orna mental use. There are attractive reproductions of early werewere mademade andand whywhy a particularparticular stylestyle waswas chosen.chosen. mental use. There are attractive reproductions of early mapmapss andand panoramaspanoramas andand sectionssections havhavee theitheirr owownn listlistss ooff ToTo covercover thisthis greatgreat rangrangee ofof topicstopics meansmeans thatthat referencesreferences,, thougthoughh thesethese areare shortshort andand thertheree iiss nnoo generalgeneral considerableconsiderable selectionselection hahass hadhad ttoo bbee exercisedexercised andand thethe bookbook bibliographybibliography.. AsAs alwaysalways withwith thisthis series,series, ththee printing,printing, succeedssucceeds inin keepingkeeping a balancebalance betweebetweenn ages,ages, methodsmethods ooff photographyphotography andand generalgeneral layoutlayout isis beyonbeyondd reproach.reproach. manufacturemanufacture,, stylesstyles andand gemstones.gemstones. WhileWhile thethe jewelleryjewellery ReadersReaders areare warnedwarned thatthat atat thethe timetime ofof writinwritingg fivfivee issuesissues historian will welcome the conjunction of so many necklace historian will welcome the conjunction of so many necklace outout ofof thethe firstfirst eleveneleven areare alreadyalready outout ofof printprint:: reprintingreprinting examples,examples, ththee gemmologistgemmologist willwill alsoalso learnlearn somethingsomething aboutabout maymay notnot alwaysalways bebe anan optionoption andand thethe second-handsecond-hand marketmarket whwhyy particularparticular stonesstones areare well-suitedwell-suited toto thisthis formform ofof display:display: shouldshould bebe contactedcontacted beforebefore thesthesee magnificentmagnificent surveyssurveys ooff thethe generalgeneral reader,reader, comingcoming acrossacross a bookbook soso reasonablyreasonably speciesspecies andand areasareas becomebecome unavailableunavailable.. SoSo fafarr emerald,emerald, priced,priced, wilwilll dipdip intointo itit andand decidedecide toto buybuy it.it. rockrock crystal,crystal, fluorite,fluorite, tourmaline,tourmaline, opaopall anandd garnegarnett havehave TheThe materialmaterial isis arrangedarranged chronologically,chronologically, thusthus placingplacing beenbeen published,published, amongamong othersothers aimedaimed aatt ororee mineralmineral thethe necklacesnecklaces ofof antiquityantiquity firstfirst andand present-daypresent-day onesones last.last. collectorscollectors butbut notnot withouwithoutt significancsignificancee ttoo thethe ThiThiss surveysurvey isis completedcompleted inin fivefive chapters,chapters, whichwhich areare gemmologist.gemmologist. M.O'D.M.O'D. ].J. Gemm., 1998,1998,26,2, 26, 2, 132-134132-134 Proceedings of the Gemmological Association and Gem Testing Laboratory of Great Britain and Notices OBITUARY Mr John B. Taylor, FGA (D. 1979), Brisbane, GIFTS TO THE ASSOCIATION Queensland, Australia, died on 22 June 1997. The Association is most grateful to the Mr Philip G. Wyer, FGA, DGA (FGA 1964, following for their gifts for research and DGA 1965), Edgbaston, Birmingham, died on 3 teaching purposes: November 1997. Argyle Diamonds, West Perth, WA, Australia, for the videos The brilliant light of Australia and The diamond pipe line. NEWS OF FELLOWS Mr John R. Führbach, Amarillo, Texas, At the invitation of Dr Frank Placido of the USA, for 8 cut peridots. Physics Department, Paisley University, Alan 135 Miss Frances Garrett, Crawley, West Hodgkinson set up the Hodgkinson method of visual Sussex, for a cellulose bracelet and a sphere of optics to demonstrate a series of hands-on quartz. experiments at a two-week open campus for secondary school pupils interested in working for Mrs Sonia Glaser, Galle, Sri Lanka, for 194 a degree in physics. Demonstrations included the rough and cut stones. measurement of refraction, birefringence, Mr Robert Hsu, Taipei, Taiwan, for a dispersion and the use of a thermal probe and financial donation. Hanneman Diamond Eye for the distinction of diamonds. Alan Hodgkinson has also been invited Mr David Pratt, Bradford, West Yorkshire, to lecture on Visual optics at Rhode Island for 7 pieces of ivory and 26 assorted cut University, New York State. The University has stones. incorporated the Hodgkinson Method in its Physics Department gemmology course as L.M. Van Moppes & Son Ltd, London, for standard syllabus for the last three years. 50 boart diamonds. In addition to his involvement on the courses mentioned above, Alan Hodgkinson has had a very busy lecture programme including 1967, has been appointed Lecturer in charge of all presentations to the National Trust for Scotland gemmological work at the University. and the East Kilbride Historical Society in autumn Peter Read gave a talk on the identification of 1997, to the American Gem Society at Anaheim, synthetic gem-quality diamonds and the new California, and, together with Richard Hughes, diamond simulant, synthetic moissanite, to the E. Alan Jobbins, Stephen Kennedy and Wessex branch of the National Association of Colin Winter, at the American Gemological Goldsmiths on 28 January 1998. He concluded his Assocation Symposium held at the Tucson talk with an illustrated review of his development Gem Show. work on the Brewster-angle meter. A prototype Michael O'Donoghue, Lecturer in meter was then used by NAG members to identify Gemmology at London Guildhall University since a selection of gemstones. © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355^4565 MEMBERS'MEMBERS' MEETINGSMEETINGS OnOn 2222 FebruaryFebruary inin thethe GeologyGeology DepartmenDepartmentt ooff thethe NationalNational MuseumMuseumss ofof Scotland,Scotland, Edinburgh,Edinburgh, TripTripss andand TourTourss CliveClive BurchBurch andand JohnJohn HarrisHarris rarann a practicapracticall dayday entitledentitled Photographing gemstones and theirtheir A fieldfield triptrip toto Whitby,Whitby, Yorkshire,Yorkshire, waswas heldheld overover inclusions. thethe weekendweekend 6 toto 8 March.March. AAss wellwell asas huntinghunting forfor jejett onon thethe beachesbeaches,, visitsvisits ttoo a workshoworkshopp andand a locallocal museumuseumm werewere arranged.arranged. A reportreport ofof thethe triptrip willwill bbee publishedpublished inin ththee JuneJune issueissue ofof Gem and and Jewellery Jewellery GEGEMM DIAMONDDIAMOND News. EXAMINATIONEXAMINATIONSS InIn JanuaryJanuary 1998,1998, 4343 candidatescandidates sasatt ththee GeGemm London DiamondDiamond ExaminationExamination worldwideworldwide ooff whomwhom London 3535 qualified,qualified, 5 withwith Distinction.Distinction. TheThe names ooff thethe OnOn 1414 JanuaryJanuary 19981998 atat thethe GemGem TutorialTutorial Centre,Centre, successfulsuccessful candidatescandidates areare listedlisted belowbelow:: 2727 GrevilleGreville Street,Street, LondonLondon EClNEC1N 8SU,8SU, ClareClare LawrencLawrencee gavegave anan illustratedillustrated talktalk entitledentitled Chinese snuff bottles: the the use use of ofstone stone in Chinesein Chinese art. art. Qualified with with Distinction Distinction OnOn 1818 FebruaryFebruary atat thethe GemGem TutorialTutorial Centre,Centre, AoAo Yan,Yan, Beijing,Beijing, P.RPR. ChinaChina BriaBriann Jackson,Jackson, ChairmanChairman ofof ththee ScottishScottish BranchBranch ooff HuHu Chin-Ching,Chin-Ching, Taipei,Taipei, Taiwan,Taiwan, R.ORO.. ChinaChina ththee GAGTL,GAGTL, gavegave a taltalkk onon collectingcollecting gemstonesgemstones inin LiLi Jian,Jian, Beijing,Beijing, P.RPR. ChinaChina Scotland.Scotland. LiuLiu AyAy Hwa,Hwa, Taipei,Taipei, Taiwan,Taiwan, R.O.R.O. ChinaChina OnOn 1818 MarchMarch atat thethe GemGem TutorialTutorial Centre,Centre, LiuLiu Jian,Jian, Beijing,Beijing, P.RPR. ChinaChina DrDr JackJack Ogden,Ogden, ChiefChief ExecutivExecutivee ofof thethe NationalNational AssociatioAssociationn ofof GoldsmithsGoldsmiths andand SecretarySecretary GeneralGeneral Qualified ofof CIBJO,CIBJO, gavegave a talktalk entitledentitled Fired with with enthusiasm: enthusiasm: the earlyearly history history of ofenamel. enamel. Balzan,Balzan, CortneyCortney G.,G., SanSan Francisco,Francisco, Calif.,Calif., USUSAA ChaChann KwongKwong Chi,Chi, HongHong KongKong 136136 ChenChen Lili,Lili, Wuhan,Wuhan, Hubei,Hubei, P.RPR. ChinaChina MidlandsMidlands BrancBranchh Gandhi,Gandhi, AmarAmar A.A.,A.A., Stanmore,Stanmore, MiddlesexMiddlesex GaoGao Bin,Bin, Wuhan,Wuhan, Hubei,Hubei, P.RPR. ChinaChina OnOn 3300 JanuaryJanuary 19981998 atat ththee DiscoveryDiscovery Centre,Centre, HuangHuang YichunYichun,, BeijingBeijing,, P.RPR. ChinaChina 77 VyseVyse Street,Street, Birmingham,Birmingham, aa BringBring andand BuyBuy SaleSale HuangHuang Yizhi,Yizhi, Wuhan,Wuhan, Hubei,Hubei, P.RPR. ChinaChina andand PracticalPractical GemmologyGemmology QuizQuiz werewere held.held. Iannicelli,Iannicelli, Marco,Marco, Salerno,Salerno, ItalyItaly OnOn 2727 FebruaryFebruary atat thethe DiscoveryDiscovery Centre,Centre, Kabangi,Kabangi, Nsapu,Nsapu, LeyLeyton ton,, LondonLondon MichaeMichaell HoughtonHoughton ofof PhoenixPhoenix FarFar EastEast PearlsPearls LtdLtd Karim,Karim, Zapherali,Zapherali, LeicesterLeicester gavgavee a talktalk onon ChineseChinese andand JapaneseJapanese pearls.pearls. Kemp,Kemp, MargaretMargaret A.,A., Backwell,Backwell, SomersetSomerset LiLi Hongjun,Hongjun, Wuhan,Wuhan, HubeiHubei,, P.RPR. ChinaChina OnOn 2222 March,March, ProfessorProfessor R.ARA.. Howie,Howie, PresidentPresident LiLi Li,Li, Beijing,Beijing, P.RPR. ChinaChina ofof thethe GAGTL,GAGTL, gavegave a lecturelecture onon gemstones,gemstones, LiLi Li,Li, Wuhan,Wuhan, Hubei,Hubei, P.RPR. ChinaChina illustratedillustrated byby slidesslides andand specimens.specimens. LuLu Xin,Xin, Wuhan,Wuhan, Hubei,Hubei, P.R.PR. ChinaChina OnOn 2277 MarchMarch atat thethe DiscoveryDiscovery CentreCentre a talktalk waswas LuLu YungYung Ching,Ching, Taipei,Taipei, Taiwan,Taiwan, RO.R.O. ChinaChina givengiven bbyy DrDr JackJack Ogden.Ogden. Liile,Liile, <;:igdem,Çigdem, Ankara,Ankara, TurkeyTurkey Maralla,Marolla, Marianna,Marianna, Athens,Athens, GreeceGreece Mitchell,Mitchell, Susannah,Susannah, NewtonNewton bbyy Tattenhall,Tattenhall, NorthNorth WesWestt BrancBranchh CheshireCheshire Panagopoulou,Panagopoulou, Anastasia,Anastasia, Athens,Athens, GreeceGreece OnOn 1818 MarchMarch atat ChurchChurch House,House, HanoverHanover Street,Street, QuQu Li,Li, Beijing,Beijing, P.R.PR. ChinaChina LiverpoolLiverpool 1,1, DavidDavid J.J. CallaghanCallaghan gavegave an an illustratedillustrated Renard-Richard,Renard-Richard, JoelleJoëlle M.,M., Ruislip,Ruislip, MiddlesexMiddlesex talktalk entitledentitled The beauty beauty of of opal. opal. Seligman,Seligman, Dominic,Dominic, Southfields,Southfields, LondonLondon Slater,Slater, RichardRichard M.,M., Radstock,Radstock, Bath,Bath, AvoAvonn ScottishScottish BranchBranch SunSun Jingyu,Jingyu, Wuhan,Wuhan, Hubei,Hubei, P.R.PR. ChinaChina TangTang YunYun Hing,Hing, Frances,Frances, HonHongg KongKong OnOn 2525 JanuaryJanuary 1998,1998, membersmembers joined joined thethe EastEast of of WebsterWebster,, PaulPaul T.,T., Greenford,Greenford, MiddlesexMiddlesex ScotlandScotland JewellersJewellers AssociatioAssociationn atat theirtheir Burns'Burns' WongWong TiTi Yin,Yin, Heather,Heather, HongHong KongKong SupperSupper inin thethe WitcheryWitchery Restaurant,Restaurant, SecretSecret Garden,Garden, YanYangg Hong,Hong, Beijing,Beijing, P.R.PR. ChinaChina EdinburghEdinburgh.. ZhuZhu Ling,Ling, Wuhan,Wuhan, Hubei,Hubei, P.RPR. ChinaChina J./. Gemm., 1998,1998,26,2,135-141 26, 2,135-141 FORTHCOMING EVENTS FORTHCOMING EVENTS 22 April London. Pearls - a Fashion Opportunity. Christianne Douglas. 22 April London. Pearls - a Fashion Opportunity. Christirume Douglas. 24 April Midlands Branch. AGM followed by A Mosaic of Gemmological 24 April Midlands Branch. AGM followed by A Mosaic of Gemmological TesseraTessera.. 2266 ApriAprill MidlandMidlandss Branch.. DiplomDiplomaa pre-examinatiopre-examinationn seminar.seminar. 3 MaMayy MidlandMidlandss Branch.. PreliminarPreliminaryy pre-examinatiopre-examinationn seminar. 8-18-100 MaMayy ScottisScottishh BranchBranch.. AnnuaAnnuall ConferencConferencee anandd AGMAGM,, PeeblesPeebles.. SpeakersSpeakers will include Gail Levine and Howard Rubin from America. will include Gail Levine and Howard Rubin from America. 1133 MaMayy LondonLondon.. ThThee GemstonGemstonee CollectionsCollections ooff ththee GAGTLGAGTL.. DrDr RogerRoger Harding.. 2200 MaMayy NortNorthh WesWestt BranchBranch.. Time-bombTime-bomb oorr funfun?? BriaBriann Dunn.Dunn. 29-329-311 MaMayy GeGemm tritripp ttoo Scotland.Scotland. TheThe weekenweekendd wilwilll includincludee a fieldfield triptrip ttoo thethe CampsiCampsiee FellsFells,, a visivisitt ttoo ththee NationaNationall MuseumsMuseums ofof ScotlandScotland andand a lecturlecturee oonn ththee gemstonesgemstones ofof ScotlandScotland bbyy BriaBriann Jackson.Jackson. 2299 JuneJune London.London. AGMAGM (GAGTL(GAGTL membersmembers only)only) followedfollowed byby thethe ReunionReunion ofof MemberMemberss anandd a BrinBringg andand BuyBuy SaleSale.. 8 JulyJuly London.London. TheThe EvolutionEvolution ofof GeorgianGeorgian andand VictorianVictorian Jewellery.Jewellery. John Benjamin. 137 John Benjamin. 137 16 September North West Branch. Gem collection with a11ecdotes. John Pyke, Snr. 16 September North West Branch. Gem collection with anecdotes. John Pyke, Snr. 3 October Trade Dinner. To be held at the Cafe Royal, Regent Street, London. 3 October GuestTrade speaker:Dinner. TGeoffreyo be hel dC. aMunnt the Caf. é Royal, Regent Street, London. Guest speaker: Geoffrey C. Munn. 2211 OctobeOctoberr NorthNorth WesWestt BranchBranch.. SilversmithSilversmith ofof WilliamsburWilliamsburgg 1780.1780. MartinMartin Connard. 1 NovemberNovember AnnualAnnual Conference.Conference. GemsGems inin Jewellery.Jewellery. ToTo bebe heldheld inin thethe BarbicanBarbican Centre,Centre, London.London. 1818 NovembeNovemberr NortNorthh WesWestt BranchBranch.. AnnuaAnnuall GeneralGeneral Meeting.Meeting. ForFor furtherfurther informatioinformationn oonn ththee abovabovee eventeventss contact:contact: LondoLondonn anandd Trips:Trips: MarMaryy BurlandBurland onon 01714040171 404 33343334 MidlandMidlandss BranchBranch:: GwynGwyn GreenGreen onon 01210121 4455359445 5359 NortNorthh WesWestt Branch:Branch: DeannaDeanna BradyBrady onon 01510151 648648 42664266 ScottishScottish BranchBranch:: JorumaJoanna ThomsonThomson onon 0172101721 722936722936 GAGTLGAGTL WEBWEB SITSITEE ForFor up-to-the-minutup-to-the-minutee informationinformation onon GAGTLGAGTL eventsevents andand workshopsworkshops visit our web site on www.gagtl.ac.uklgagtl visit our web site on www.gagtl.ac.uk/gagtl ProcProceedingseedings and and Notices Notices EXAMINATIONSEXAMINATIONS ININ Rowntree,Rowntree, Josephine,Josephine, Knaresborough,Knaresborough, NorthNorth GEMMOLOGY YorkshirYorkshiree GEMMOLOGY SandarSandar Win,Win, Yangon,Yangon, MyanmarMyanmar InIn thethe ExaminationsExaminations inin Gemmology,Gemmology, heldheld Song,Song, Ruohan,Ruohan, Shanghai,Shanghai, P.R. ChinaChina worldwideworldwide inin JanuaryJanuary 1998,1998, 127127 candidatescandidates satsat forfor Tinnyunt,Tinnyunt, EmmaEmma J.,J., KensalKensal Green,Green, LondonLondon ththee PreliminaryPreliminary ExaminationExamination ofof whomwhom 9393 TongTong Tao,Tao, Guilin,Guilin, Guangxi,Guangxi, P.R. ChinaChina qualified.qualified. InIn ththee DiplomaDiploma ExaminationExamination 113113 sat,sat, ooff Tupper,Tupper, MichaelMichael I.,I., SouthSouth Holmwood,Holmwood, SurreySurrey whowhomm 5353 qualfiiedqualfiied,, threthreee witwithh Distinction.Distinction. TheThe WangWang Chao,Chao, GuilinGuilin Guangxi,Guangxi, P.R. ChinaChina namenamess ofof thethe successfulsuccessful candidatescandidates areare asas follows:follows: WanWangg Cun,Cun, Wuhan,Wuhan, Hubei,Hubei, P.R.P.R. ChinaChina WangWang Mingxun,Mingxun, Wuhan,Wuhan, Hubei,Hubei, P.R. ChinaChina WWuu Shizhou,Shizhou, Guilin,Guilin, Guangxi,Guangxi, P.R. ChinaChina Xiang Xiaodan, Wuhan, Hubei, P.R. China DiplomaDiploma Xiang Xiaodan, Wuhan, Hubei, P.R China XiXiee Bing,Bing, Wuhan,Wuhan, Hubei,Hubei, P.R. ChinaChina Qualified with with Distinction Distinction ZhangZhang Caixia,Caixia, Shanghai,Shanghai, P.R. ChinaChina ZhaZhaoo Yanzeng,Yanzeng, Guilin,Guilin, Guangxi,Guangxi, P.R. ChinaChina Liu Huai, Wuhan, Hubei, P.R. China Liu Huai, Wuhan, Hubei, P.R China ZhengZheng Kaiwen,Kaiwen, Wuhan,Wuhan, HubeiHubei,, P.R. ChinaChina Park,Park, ChanChan Won,Won, Taegu,Taegu, RO.R.O. KoreaKorea ZiziZizi Zheng,Zheng, Guilin,Guilin, Guangxi,Guangxi, P.R. ChinaChina PreliminaryPreliminary Aster, Flora, London Qualified Aster, Flora, London Blatherwick,Blatherwick, Clare,Clare, LondonLondon AndaluAndaluzz Sanchez,Sanchez, Maria,Maria, Peckham,Peckham, LondonLondon Brown,Brown, Vanessa,Vanessa, Sittingbourne,Sittingbourne, KentKent AndersonAnderson,, ElizabethElizabeth A.,A., Peacehaven,Peacehaven, EastEast SussexSussex Browne,Browne, Dione,Dione, Battersea,Battersea, LondonLondon BanksBanks,, Michelle,Michelle, Leicester.Leicester. ChanChan KamKam Wai,Wai, Carolyn,Carolyn, HongHong KongKong Boccard,Boccard, Jean-Marie,Jean-Marie, Geneva,Geneva, SwitzerlandSwitzerland ChenChen Pai-Rong,Pai-Rong, Taipei,Taipei, Taiwan,Taiwan, RO.R.O. ChinaChina BrittonBritton,, AndreaAndrea L.,L., Woking,Woking, SurreySurrey Cheong-LyCheong-Ly KarineKarine,, LondonLondon ChanChan SauSau King,King, NewNew Territories,Territories, HongHong KongKong Cho,Cho, Chang-Bae,Chang-Bae, Taejon,Taejon, RO.R.O. KoreaKorea ChenChen XiataoXiatao,, Wuhan,Wuhan, Hubei,Hubei, P.RPR. ChinaChina Cropp,Cropp, AlastairAlastair ER,F.R., Lewes,Lewes, EastEast SussexSussex 138 138 Davidge,Davidge, ElizabethElizabeth A.A.,, Pimlico,Pimlico, LondonLondon Curran,Curran, Rose,Rose, Ealing,Ealing, LondonLondon DraperDraper,, ZoeZoe S.,S., UpperUpper Abbeywood,Abbeywood, LondonLondon dede Vries,Vries, Marius,Marius, SouthSouth Kensington,Kensington, LondonLondon HaHann Lirong,Lirong, Wuhan,Wuhan, Hubei,Hubei, P.R. ChinaChina DunDun YeeYee Man,Man, Stella,Stella, Chaiwan,Chaiwan, HongHong KongKong HoHo Chuan-Hsiang,Chuan-Hsiang, TaipeiTaipei,, TaiwanTaiwan,, R.O.R.O. ChinaChina Eggerbratt,Eggerbratt, Pauline,Pauline, Sundbyberg,Sundbyberg, SwedenSweden Holt,Holt, JudithJudith A.,A., Darwen,Darwen, LancashireLancashire FanFan Liying,Liying, Shanghai,Shanghai, P.R. ChinaChina HsieHsiehh PaoPao Lien,Lien, HongHong KongKong Fris,Fris, Arnold,Arnold, Goedereede,Goedereede, TheThe NetherlandsNetherlands HtuHtunn Han,Han, Yangon,Yangon, MyanmarMyanmar Fujinara,Fujinara, Motoko,Motoko, LondonLondon HuHu Chin-Ching,Chin-Ching, Taipei,Taipei, Taiwan,Taiwan, RO.R.O. ChinaChina FungFung WaiWai Man,Man, Winnie,Winnie, Shaukeiwan,Shaukeiwan, HonHongg KongKong IannicelliIannicelli,, Marco,Marco, Salerno,Salerno, ItalyItaly Garrett,Garrett, FrancesFrances S.J.,S.J., Crawley,Crawley, WestWest SussexSussex JacquatJacquat,, Stephane,Stephane, Geneva,Geneva, SwitzerlandSwitzerland Grech,Grech, Carrieann,Carrieann, Richmond,Richmond, SurreySurrey JiJi Tianxi,Tianxi, Shanghai,Shanghai, P.R. ChinaChina Greenfield,Greenfield, DawnDawn M.,M., Eynsford,Eynsford, KentKent JohnJohn,, VictoriaVictoria A.,A., AgaAgarr Grove,Grove, LondonLondon Gudmundson,Gudmundson, IngerInger M.,M., Lannavaara,Lannavaara, SwedenSweden Kiefert,Kiefert, Lore,Lore, Basel,Basel, SwitzerlandSwitzerland Gwati,Gwati, Martha,Martha, Harare,Harare, ZimbabweZimbabwe Krzemnicki,Krzemnicki, MichaelMichael S.,S., BaselBasel,, SwitzerlandSwitzerland HanHan Xiao,Xiao, Guilin,Guilin, Guangxi,Guangxi, P.R. ChinaChina LianLiangg Weizhang,Weizhang, Guangzhou,Guangzhou, P.R. ChinaChina Harrison,Harrison, TarnTarn J.,J., LeamingtonLeamington Spa,Spa, WarwickshireWarwickshire LinLin,, ChiefChief R,R., Kaohsiung,Kaohsiung, Taiwan,Taiwan, RO.R.O. ChinaChina Henry-StogdonHenry-Stogdon,, SarahSarah A.,A., SuttonSutton CommonCommon,, SurreySurrey LinLin YiYi Hwa,Hwa, Yangon,Yangon, MyanmarMyanmar Hong,Hong, AngelaAngela SweeSwee Leng,Leng, LondonLondon LingLing Li,Li, Shanghai,Shanghai, P.R. ChinaChina Hunter,Hunter, PaulinePauline A.,A., Caversfield,Caversfield, OxfordshireOxfordshire LiLiuu Yujun,Yujun, Wuhan,Wuhan, Hubei,Hubei, P.R. ChinaChina Ikebe,Ikebe, Emi,Emi, LondonLondon Lodge,Lodge, Tim,Tim, MuswellMuswell HillHill,, LondonLondon IpIp KitKit Ling,Ling, NewNew Territories,Territories, HongHong KongKong MillardMillard,, SimonSimon R,R., Corsham,Corsham, WiltshireWiltshire Jain,Jain, ReenaReena,, Jaipur,Jaipur, IndiaIndia MuttonMutton,, Valerie,Valerie, Langley,Langley, BuckinghamshireBuckinghamshire Kang,Kang, Sung-Oong,Sung-Oong, Taegu,Taegu, RO.R.O. KoreaKorea Nazos,Nazos, KonstantinosKonstantinos I.,I., AthensAthens,, GreeceGreece Kassas,Kassas, Demetrios,Demetrios, Larissa,Larissa, GreeceGreece 00,Oo, TheinThein Lwin,Lwin, Yangon,Yangon, MyanmarMyanmar Kellerson,Kellerson, LaurentLaurent P.,P., LondonLondon PancratzPancratz,, Mark,Mark, Weybridge,Weybridge, SurreySurrey Kerkhof,Kerkhof, PeterPeter A.M.,A.M., Eindhoven,Eindhoven, TheThe NetherlandsNetherlands ParkPark,, SungSung Ok,Ok, Taegu,Taegu, RO.R.O. KoreaKorea Koh,Koh, HockHock Heng,Heng, SingaporeSingapore QianQiangg Yin,Yin, Shanghai,Shanghai, P.R. ChinaChina Konstandopoulou,Konstandopoulou, Garoufallia,Garoufallia, LondonLondon RommensRommens,, CatharinaCatharina M.C.M.e.,, Eindhoven,Eindhoven, TheThe LaiLai HoiHoi Shan,Shan, Kowloon,Kowloon, HongHong KongKong NetherlandNetherlandss LanzLanz,, Ernst,Ernst, Veytaux,Veytaux, SwitzerlandSwitzerland J.J. Gemm., 1998, 26, 2, 135-141135-141 GEMGEM TUTORIALTUTORIAL CENTRECENTRE 2727 GrevilleGreville Street,Street, LondonLondon ECINEC1N 8SU8SU SYNTHETICSSYNTHETICS ANDAND ENHANCEMENTSENHANCEMENTS TODAYTODAY 2828 andand 2929 AprilApril AreAre youyou awareaware ofof thethe variousvarious treatedtreated andand syntheticsynthetic materialsmaterials thatthat areare likelylikely toto bebe masqueradingmasquerading amongstamongst thethe stostoneness youyou areare bubuyinyingg andand selling?selling? WhetherWhether youyou areare valuingvaluing,, repairingrepairing oror dealing,dealing, cancan youyou affordafford toto missmiss thesethese twotwo daysdays ofof investigation?investigation? Price £198 £198 + +VAT VAT (£232.65) (£232.65) - includes - includes sandwich sandwich lunches lunches STUDENTSTUDENT WORKSHOPSWORKSHOPS PreliminaryPreliminary TheoryTheory ReviewReview 18May18 May Three-dayThree-day PreliminaryPreliminary WorkshopWorkshop 18-2018-20 MayMay DiplomaDiploma TheoryTheory ReviewReview 11 Jun Junee Four-dayFour-day DiplomaDiploma WorkshopWorkshop 1-41-4 JuneJune Two-dayTwo-day DiplomaDiploma PracticalPractical WorkshopWorkshop 6-76-7 June June WeekendWeekend DiamondDiamond GradingGrading RevisionRevision 6-76-7 JuneJune ForFor furtherfurther detailsdetails contactcontact thethe GAGTLGAGTL EducationEducation DepartmentDepartment Tel:Tel : +44+44 (0)171(0)171 4043334404 3334 Fax:Fax : +44+44 (0)171(0)171 404404 88438843 139 139 LeeLee ChunChun ManMan,, HongHong KongKong Roberts,Roberts, JustiJustinn J.,J., Wembley,Wembley, MiddlesexMiddlesex LeeLee KwaKwann SuiSui Ying,Ying, YelineYeline,, Kowloon,Kowloon, HongHong KongKong Said,Said, MohammadMohammad Ali,Ali, LannavaaraLannavaara,, SwedenSweden LeeLee SiuSiu YingYing KwanKwan,, FannyFanny,, HongHong KongKong Savla,Savla, RajveRajveee B.,B., Bangalore,Bangalore, IndiaIndia LiLi YaYatt Choi,Choi, Kowloon,Kowloon, HonHongg KongKong Schmocker,Schmocker, KarinKarin,, Fribourg,Fribourg, SwitzerlandSwitzerland LiuLiu Pei-Chin,Pei-Chin, Taipei,Taipei, Taiwan,Taiwan, RO.R.O. ChinaChina Shin,Shin, Hyun-Sook,Hyun-Sook, Daejon,Daejon, R.ORO.. KoreaKorea LoeLoe ShueShue Mon,Mon, Taipei,Taipei, Taiwan,Taiwan, RO.R.O. ChinaChina Smith,Smith, PeggPeggyy E.J.,E.J., Rochester,Rochester, KentKent LongLong Chu,Chu, Guilin,Guilin, Guangxi,Guangxi, RRP.R. ChinaChina Smith,Smith, WaynWaynee M.,M., Harrogate,Harrogate, YorkshireYorkshire Liile,Lüle, <;igdem,Çigdem, Ankara,Ankara, TurkeyTurkey SoeSoe MoMoee NaingNaing,, Yangon,Yangon, MyanmarMyanmar McFarlin,McFarlin, Michael,Michael, Amarillo,Amarillo, Texas,Texas, USAUSA Srithai,Srithai, Boontarika,Boontarika, LondonLondon Mafara,Mafara, EzekielEzekiel M.,M., Harare,Harare, ZimbabweZimbabwe SuSu ChoCho Win,Win, Yangon,Yangon, MyanmarMyanmar Martin,Martin, Edward,Edward, St.St. Ouen,Ouen, Jersey,Jersey, ChannelChannel IslandsIslands Suda,Suda, JunkoJunko,, LondonLondon MaungMaung AunAungg MinMin,, Yangon,Yangon, MyanmarMyanmar SunSun PinghongPinghong,, Shanghai,Shanghai, RRP.R. ChinaChina MyoMyo ThawThaw LinLin,, YangonYangon,, MyanmarMyanmar Sung,Sung, Jae-BumJae-Bum,, Daejon,Daejon, R.ORO.. KoreaKorea NangNang LattLatt LattLatt Htun,Htun, YangonYangon,, MyanmarMyanmar Suwichakornpong,Suwichakornpong, Sirima,Sirima, KensingtonKensington,, LondonLondon Notaro,Notaro, TinaTina M.M.,, Kandy,Kandy, SrSrii LankaLanka TangTang SukSuk YeeYee,, NewNew TerritoriesTerritories,, HonHongg KongKong O'Byrne,O'Byrne, Rose-Marie,Rose-Marie, BicesterBicester,, OxfordshireOxfordshire TangTang TiandeTiande,, Wuhan,Wuhan, HubeiHubei,, RRP.R. ChinaChina Okamoto,Okamoto, Chizuko,Chizuko, LondonLondon TharnTharn Htite,Htite, Yangon,Yangon, MyanmarMyanmar Ono,Ono, Shiho,Shiho, LondonLondon Thompson,Thompson, IanIan,, WoodWood GreenGreen,, LondonLondon PangPang ChiChi KeungKeung,, Shatin,Shatin, HongHong KongKong ToTo MaMann FangFang,, HongHong KongKong Panoutsopoulou,Panoutsopoulou, DolomidouDolomidou G.,G., AthensAthens,, GreeceGreece Tsakanika,Tsakanika, Christina,Christina, AthensAthens,, GreeceGreece Paphitis,Paphitis, ConstantinConstantinos os,, BayswaterBayswater,, LondonLondon Tulo,Tulo, KarenKaren,, LondonLondon Park,Park, ChanChan Won,Won, Taegu,Taegu, R.ORO.. KoreaKorea VanVan Spaendonck,Spaendonck, AnoukAnouk D.D.,, ThThee HagueHague,, TheThe Parker,Parker, SarahSarah J.J.,, EastEast DulwichDulwich,, LondonLondon NetherlandNetherlandss Patel,Patel, Nita,Nita, Newbury,Newbury, BerkshireBerkshire Vasilevskaya,Vasilevskaya, Polina,Polina, SanSan Francisco,Francisco, Calif.,Calif., USAUSA Pavlou,Pavlou, Tasos,Tasos, Nicosia,Nicosia, CyprusCyprus WangWang Ming-chiMing-chi,, Taipei,Taipei, TaiwanTaiwan,, RO.R.O. ChinaChina Pedersen,Pedersen, Gunnar,Gunnar, Lannavaara,Lannavaara, SwedenSweden YinYin ShengSheng Shen,Shen, Shanghai,Shanghai, P.RRR. ChinaChina QiangQiang YinYin,, Shanghai,Shanghai, P.RRR. ChinaChina Zagana,Zagana, Aphrodite,Aphrodite, AthensAthens,, GreeceGreece Rambukkange,Rambukkange, TimothyTimothy RP.,, Kandy,Kandy, SriSri LankaLanka ZhouZhou WeWenn Hao,Hao, Guilin,Guilin, GuangxiGuangxi,, P.RRR. ChinaChina Proceedings andand NoticesNotices MEETINGMEETINGSS OOFF THTHEE COUNCILCOUNCIL Morris,Morris, DavidDavid John,John, Stoke,Stoke, Plymouth,Plymouth, DevoDevonn OFOF MANAGEMENTMANAGEMENT MuratsuMuratsu,, Hirotoshi,Hirotoshi, NeyagawaNeyagawa CityCity,, Osaka,Osaka, JapanJapan NemotoNemoto,, Kyoko,Kyoko, Kyou-TanabeKyou-Tanabe CityCity,, KyotoKyoto,, JapanJapan AtAt a meetingmeeting ofof thethe CouncilCouncil ofof ManagementManagement NicholNichol,, Douglas,Douglas, Wrexham,Wrexham, NorthNorth WaleWaless helheldd atat 2727 GrevilleGreville Street,Street, LondonLondon EClNEC1N 8SU,8SU, onon 2828 Nilsson,Nilsson, PaulPaul Graham,Graham, Auckland,Auckland, NeNeww ZealandZealand JanuaryJanuary 19981998 thethe businesbusinesss transactedtransacted includedincluded ththee Nishimura,Nishimura, Yoko,Yoko, NabariNabari City,City, MieMie Pref.,Pref., JapanJapan electionelection ofof thethe following:following: Nishioka,Nishioka, Kimie,Kimie, OsakaOsaka City,City, Osaka,Osaka, JapanJapan Okamoto,Okamoto, Mayumi,Mayumi, Higashi-OsakaHigashi-Osaka CityCity,, Osaka,Osaka, JapanJapan DiamondDiamond MembershipMembership anandd Onohara,Onohara, Miwa,Miwa, KobeKobe City,City, Hyogo,Hyogo, JapanJapan FellowshipFellowship (FGAIDGA)(FGA/DGA) Oya,Oya, Kenichi,Kenichi, NiigatNiigataa City,City, NiigatNiigataa Pref.Pre£.,, JapanJapan Plant,Plant, Monika,Monika, Altrincham,Altrincham, CheshireCheshire PatelPatel,, Pankaj,Pankaj, SudburySudbury HillHill,, MiddxMiddx.. 1991,19921991,1992 Sakai,Sakai, Junko,Junko, OtsuOtsu City,City, ShigaShiga Pre£.,Pref., JapanJapan TaylorTaylor,, Roger,Roger, Birmingham,Birmingham, Warwicks.Warwicks. 1986,1986,199 19944 Sanui,Sanui, Atsuko,Atsuko, KawanishiKawanishi City,City, HyogoHyogo Pref.Pref.,, JapanJapan Smith,Smith, Christopher,Christopher, Lucerne,Lucerne, SwitzerlandSwitzerland Takayama,Takayama, Rie,Rie, KyotoKyoto City,City, Kyoto,Kyoto, JapanJapan FellowshipFellowship (FGA(FGA)) Tanimura,Tanimura, Hiromi,Hiromi, OsakaOsaka City,City, OsakaOsaka,, JapanJapan Taylor,Taylor, DuncanDuncan Lawrence,Lawrence, StowtingStowting,, NearNear Campbell,Campbell, RobertRobert Desmond,Desmond, Wallington,Wallington, Sutton,Sutton, Ashford,Ashford, KentKent Surrey.Surrey. 19951995 Thoresen,Thoresen, Lisbet,Lisbet, SantaSanta Monica,Monica, Calif.Calif.,, USUSAA KanKan WingWing Lok,Lok, Singapore.Singapore. 19951995 Tsutsumi,Tsutsumi, Masao,Masao, Higashi-HiroshimaHigashi-Hiroshima CityCity,, Karandikar,Karandikar, SurendraSurendra NarayanNarayan,, Maharashtra,Maharashtra, HiroshimaHiroshima Pref.,Pref., JapanJapan India.India. 19971997 YamamotoYamamoto,, HirokaHiroka,, OsakaOsaka City,City, Osaka,Osaka, JapanJapan KeiKei,, 00Oo 00Oo Tracy,Tracy, HongHong Kong.Kong. 19961996 YanagisawaYanagisawa,, Nobuko,Nobuko, IbarakiIbaraki City,City, OsakaOsaka,, JapanJapan LauLau JoyceJoyce PaoPao Ching,Ching, HongHong Kong.Kong. 19971997 Yawata,Yawata, Keiko,Keiko, AyaseAyase City,City, KanagawaKanagawa Pref.Pref.,, JapanJapan LeeLee YowYow Hon,Hon, HongHong Kong.Kong. 19971997 PaniPani,, Tonu,Tönu, Tartu,Tartu, Estonia.Estonia. 19961996 LaboratoryLaboratory MembershipMembership 140 PethiyagodaPethiyagoda,, UpaliUpali,, Manama,Manama, Bahrain.Bahrain. 19781978 140 Winiski,Winiski, Ken,Ken, Vancouver,Vancouver, BCBC,, Canada.Canada. 19951995 GuyGuy SteelSteel Jewellers,Jewellers, LondonLondon W1YW1Y OB20B2 RennieRennie & Co.Co . Ltd,Ltd, LondonLondon EClNEC1N 8SU8SU OrdinaryOrdinary MembershipMembership AtAt a meetinmeetingg ofof thethe CouncilCouncil ooff ManagementManagement Asanuma,Asanuma, Yukiko,Yukiko, KyotoKyoto City,City, Kyoto,Kyoto, JapanJapan helheldd atat 2727 GrevilleGreville Street,Street, LondonLondon EC1NEC1N 8SU,8SU, onon 2525 Atarashi,Atarashi, Yoshie,Yoshie, OsakaOsaka City,City, Osaka,Osaka, JapanJapan FebruaryFebruary 19981998 thethe businessbusiness transactedtransacted includedincluded Blatherwick,Blatherwick, Clare,Clare, LondonLondon thethe electionelection ofof thethe following:following: Castoro,Castoro, Loretta,Loretta, NewNew YorkYork,, N.Y.,N.Y, USUSAA FinlayFinlay;, LoudenLouden B.,B., LondonLondon FellowshipFellowship (FGA(FGA)) Gupta,Gupta, AshwaniAshwani Kumar,Kumar, WindsorWindsor,, BerkshireBerkshire Hasegawa, Takako,Takako, ToyonakaToyonaka City,City, Osaka,Osaka, JapanJapan Kjendlie,Kjendlie, Ole-Richard,Ole-Richard, Larvik,Larvik, NorwayNorway.. 19971997 HashiguchiHashiguchi,, Naoko,Naoko, SendaiSendai City,City, KagoshimaKagoshima Pref.,Pref., McCarthy,McCarthy, KieranKieran Martin,Martin, London.London. 19971997 JapanJapan VanVan derder Molen,Molen, WouterWouter NicolaasNicolaas,, ZwolleZwolle,, ThThee Higashi,Higashi, Moritomi,Moritomi, YaYaoo City,City, Osaka,Osaka, JapanJapan Netherlands.Netherlands. 19961996 Higo,Higo, Chizuyo,Chizuyo, Uda-gunUda-gun,, NaraNara Pref.,Pref., JapanJapan HoshinoHoshino,, Tomiko,Tomiko, AmagasakAmagasakii City,City, HyogoHyogo Pre£.,Pref., OrdinaryOrdinary MembershipMembership JapanJapan IkedaIkeda,, YumiYumi,, OsakaOsaka City,City, Osaka,Osaka, JapanJapan Bell-Burrow,Bell-Burrow, Briony,Briony, LondonLondon Inoue,Inoue, Kazuko,Kazuko, Tokyo,Tokyo, JapanJapan dede Vries,Vries, MariusMarius Leonardus,Leonardus, SouthSouth Kensington,Kensington, Ishibashi,Ishibashi, Shigeru,Shigeru, KishiwadaKishiwada City,City, Osaka,Osaka, JapanJapan LondonLondon JinsenjiJinsenji,, Osamu,Osamu, TodaToda City,City, SaitamaSaitama Pref.,Pref., JapanJapan Dube,Dube, Nokuthula,Nokuthula, Cambridge,Cambridge, CambsCambs KawaharaKawahara,, Miki,Miki, Enuma-gun,Enuma-gun, IshikawaIshikawa Pref.,Pref., Flynn,Flynn, Matthew,Matthew, Amersham,Amersham, BucksBucks JapanJapan Gillary,Gillary, AdamAdam Jason,Jason, Woodley,Woodley, ReadinReadingg BerksBerks.. Kishikawa,Kishikawa, Toshio,Toshio, OsakaOsaka City,City, Osaka,Osaka, JapanJapan Huddlestone,Huddlestone, JonathanJonathan David,David, LondonLondon KoukouKoukou,, Katerina,Katerina, Athens,Athens, GreeceGreece Kendall,Kendall, DavidDavid Carl,Carl, AddiscombeAddiscombe,, Croydon,Croydon, KubotaKubota,, Mie,Mie, Higashi-Chikuma-gun,Higashi-Chikuma-gun, NaganoNagano SurreySurrey Pref.,Pref., JapanJapan Kneip,Kneip, JohnJohn Richard,Richard, LondonLondon Lallerstedt,Lallerstedt, Anna,Anna, Barnes,Barnes, LondonLondon Massera,Massera, Dezith-Baka,Dezith-Baka, Stratford,Stratford, LondonLondon MomosakiMomosaki,, NobukoNobuko,, HirakataHirakata City,City, Osaka,Osaka, JapanJapan Michael,Michael, Marios,Marios, Stockwell,Stockwell, LondonLondon J.J. Gemm., 1998, 26, 2,2,135-141 135-141 Morrison, Maxine, Cold Ash, Berks. Okutu, Yula, London O'Neill, Vince, Dorchester, Dorset ADVERTISING IN Orsak, Jane, Wassenaar, The Netherlands THE JOURNAL OF Pat el, Purnima, Kintbury, Berks. Pinter, Max, London GEMMOLOGY Roth, Joan Martin, London Taylor, G. Russell, Gorseinon, Wales The Editors of the Journal invite Tete, Nair Cristina, London Van Dievoet, Daniel, Antwerp, Belgium advertisements from gemstone Yuka, Fujiwara, London and mineral dealers, publishers and others with interests in the gemmological, mineralogical, Transfers from Ordinary lapidary and jewellery fields. Membership to Fellowship (FGA) Rates per insertion, excluding VAT, Roper, Bebs, Rokeby, Tasmania, Australia, 1997 are as follows: Whole page Half page Quarter page £180 £100 £60 CORRIGENDA Enquiries to Mary Burland On p.48 above, first column, second line, for Advertising Manager 'Single-chain silicates' read 'Double-chain silicates' Gemmological Association and On the back cover of Vol. 26 (1), under Gem Testing Laboratory of Great Britain Contents, fifth item, for 'Colour in tapazes ...' read 27 Greville Street, London EC1N 8SU Colour in topazes ../ 141 Pearls Coral Amber Bead Necklaces Carvings Cameos Mineral Specimens I The World of Gemstones 1 I § i I 3. -H 3 Ruppenthal (U.K.) Limited fe; 2I* £I a. f Gemstones of every kind, cultured pearls, coral, amber, ^ 3 bead necklaces, hardstone carvings, objets d'art, ii I to 18 ct gold gemstone jewellery and antique jewellery f J We offer a first-class lapidary service. i £ £ I By appointment only J la Wickham Court Road, West Wickham, Kent BR4 9LQ Tel: 0181-777 4443, Fax: 0181-777 2321 I Antique Jewellery Modern 18 ct and 9 ct Gem-set Jewellery Proceedings and Notices 142142 WWee looklook afteafterr allall youryour insurancinsurancee PROBLEMSPROBLEMS ForFor nearlynearly a centurycentury T.H.T.H. 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Precious stone merchants also representi ng: Morris Goldman Gems Ltd 0 Chapel House, Hatton Place, ....) Hatton Garden . r\ London ECl N 8RX, England. O~ \.J' Tel: 0171-242 3181 ;.. Telex: 27726 THOMCO-G .$ oI\t Fax: 0171-831 1776 ~ Ss OF ~~ 144144 " Museums,Museums, EducationalEducational Establishments,Establishments, CollectorsCollectors & StudentsStudents I havehave whatwhat isis probablyprobably thethe largestlargest rangerange ofof genuinelygenuinely rarraree stonesstones inin thethe UK,UK, fromfrom AnalcimeAnalcime ttoo Wulfenite.Wulfenite. AlsoAlso rarraree anandd modermodernn synthetics,synthetics, andand inexpensiveinexpensive crystalscrystals andand stonesstones forfor students.students. NewNew MAGGIEMAGGIE CAMPBELLCAMPBELL PEDERSENPEDERSEN computerisedcomputerised listslists availableavailable withwith eveevenn ABIPP,ABIPP, FGFGAA moremore detail.detail. PleasePlease sendsend £2£2 inin 11sst t classclass stampstampss refundablrefundablee oonn firstfirst ordeorderr (overseas(overseas free).free). JEWELLERYJEWELLERY & GEMSTONGEMSTONEE TwoTwo specialspecial offersoffers forfor studentsstudents:: PHOTOGRAPHYPHOTOGRAPHY NeNeww TeachlBuyTeach/Buy serviceservice andand freefree stonesstones onon anan orderorder.. A.I.A J. French,French, FGAFGA 8282 BrookleyBrookley Road,Road, Brockenhurst,Brockenhurst, Tel:Tel: 0181-9940181-994 83483411 HantsHants S042S042 7R7RAA Fax:Fax:0181-72 0181-7233 42664266 L Telephone:Telephone: 0159062321401590 623214 Guide to the preparation of typescripts for publication in The Journal of Gemmology The Editor is glad to consider original articles Illustrations Either transparencies or shedding new light on subjects of gemmological photographs of good quality can be submitted interest for publication in The Journal. Articles for both coloured and black-and-white are not normally accepted which have already illustrations. It is recommended that authors been published elsewhere in English, and an retain copies of all illustrations because of the article is accepted only on the understanding risk of loss or damage either during the printing that (1) full information as to any previous process or in transit. publication (whether in English or another Diagrams must be of a professional quality language) has been given, (2) it is not under and prepared in dense black ink on a good consideration for publication elsewhere and (3) quality surface. Original illustrations will not be it will not be published elsewhere without the returned unless specifically requested. consent of the Editor. All illustrations (maps, diagrams and Typescripts Two copies of all papers should be pictures) are numbered consecutively with submitted on A4 paper (or USA equivalent) to Arabic numerals and labelled Figure 1, Figure the Editor. Typescripts should be double spaced 2, etc. All illustrations are referred to as with margins of at least 25 mm. They should be 'Figures'. set out in the manner of recent issues of The Tables Must be typed double spaced, using Journal and in conformity with the information few horizontal rules and no vertical rules. They set out below. Papers may be of any length, but are numbered consecutively with Roman long papers of more than 10 000 words (unless numerals (Table IV, etc.). Titles should be capable of division into parts or of exceptional concise, but as independently informative as importance) are unlikely to be acceptable, possible. The approximate position of the Table whereas a short paper of 400-500 words may in the text should be marked in the margin of the achieve early publication. typescript. The abstract, references, notes, captions and Notes and References Authors may choose tables should be typed double spaced on one of two systems: separate sheets. (1) The Harvard system in which authors' On matters of style and rendering, please names (no initials) and dates (and specific consult The Oxford dictionary for writers and pages, only in the case of quotations) are given editors (Oxford University Press, 1981). in the main body of the text, e.g. (Giibelin and Koivula, 1986, 29). References are listed Title page The title should be as brief as is alphabetically at the end of the paper under the consistent with clear indication of the content of heading References. the paper. It should be followed by the names (2) The system in which superscript numbers (with initials) of the authors and by their are inserted in the text (e.g .... to which Giibelin addresses. refers.3) and referred to in numerical order at the Abstract A short abstract of 50-100 words is end of the paper under the heading Notes. required. Informational notes must be restricted to the minimum; usually the material can be Key Words Up to six key words indicating the incorporated in the text. If absolutely necessary subject matter of the article should be supplied. both systems may be used. Headings In all headings only the first letter References in both systems should be set out and proper names are capitalized. as follows, with double spacing for all lines. A This is a first level heading Papers Hurwit, K., 1991. Gem Trade Lab notes. Gems & Gemology, 27, 2, 110-11 First level headings are in bold and are flush left on a separate line. The first text line Books Hughes, R.W., 1990. Corundum. following is flush left. Butterworth-Heinemann, London. p. 162 Abbreviations for titles of periodicals are B This is a second level heading those sanctioned by the World List of scientific Second level headings are in italics and are periodicals 4th edn. The place of publication flush left on a separate line. The first text line should always be given when books are following is flush left. referred to. Volume 26 No. 2 April 1998 Contents ^ J0umal of Gemmology Distinctive gem corundum suites from discrete 65 basalt fields: a comparative study of Barrington, Australia, and West Pailin, Cambodia, gemfields EL. Sutherland, D. Schwarz, E.A. Jobbins, R.R. Coenraads and G. Webb Peridot from the Black Rock Summit lava flow, 86 Nye County, Nevada, USA J.R. Fiihrbach Rubies and pink sapphires from the Pamir 103 Mountain Range in Tajikistan, former USSR C.P. Smith Gemstone deposits of the former Soviet Union 111 E.M. Spiridonov Abstracts 126 Book Reviews 132 Proceedings of the Gemmological Association and 135 Cover Picture Gem Testing Laboratory of Great Britain and Ladies' bracelet Notices A magnificent 105.57 ct peridot from Myanmar set with 35.45 ct and 35.74 ct citrines from Brazil, on ten strands of black nephrite beads (5.0-5.2 mm diameter) from Wyoming, USA. Bracelet the property of Georgia and Quentin Isaacs, Texas, USA. Photo courtesy of Copyright © 1998 J.R. Fiihrbach The Gemmological Association and (see Peridot from Gem Testing Laboratory of Great Britain Black Rock Summit Registered Office: Palladium House, 1-4 Argyll Street, London W1V 2LD lava flow, Nye County, "Nevada, USA. p. 86) ISSN: 1355-4565 Printecf'by Quadrant Offs^^uiiite^ilHBif&rd, England^