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Volume 23 No. 2. April 1992 '"* Journal of Gemmology

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Members' Council A. J. Allnutt, M.Se., G.H. Jones, B.Se., Ph.D., FGA P. G. Read, C.Eng., Ph.D., FGA H. Levy, M.Se., BA, FGA MIEE, MIERE, FGA P. J. E. Daly, B.Se., FGA J. Kessler 1. Roberts, FGA T. Davidson, FGA G. Monnickendam E.A. Thomson, R Fuller, FGA L. Music Hon. FGA D. Inkersole, FGA J.B. Nelson, Ph.D., FGS, R Velden B. Jackson, FGA F. Inst. P., C.Phys., FGA D. Warren C.H. Winter, FGA

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Examiners: A J. Allnutt, M.Se., Ph.D., FGA G. H. Jones, B.Se., Ph.D., FGA L. Bartlett, B.Se., M.Phil., FGA D. G. Kent, FGA E. M. Bruton, FGA R D. Ross, B.Se., FGA C. R Cavey, FGA P. Sadler, B.Se., FGS, FGA S. Coelho, B.Se., FGA E. Stern, FGA AT. Collins, B.Se., Ph.D Prof. LSunagawa,D.Se. A E. Farn, FGA M. Virkkunen, M.Phil., FGA B. Jackson, FGA C. Woodward, B.Se., FGA E. A Jobbins, B.Se., C. Eng., FIMM, FGA

Editor: E. A Jobbins, B.Se., C.Eng., FIMM, FGA Editorial Assistant: Mary A Burland Curator: C. R Cavey, FGA

The Genunologica1 Association and Gent Testing Laboratory of Great Britain 27 Greville Street, London EClN 8SU Telephone: 071-4043334 Fax: 071-4048843 The Journal of Gemmology

VOLUME 23 NUMBER TWO APRIL 1992

Cover Picture The photograph represents a vase carved from nephrite jade during the late Ming period (circa 1580). The original colour of the stone was probably a cream/white with a few veins and mineral inclusions. Unlike jadeite, nephrite will usually sustain heat ing to considerable temperatures, and many carvings were burnt by accident in fires, and survived the ordeal. The item illustrated is quite striking as it must have been heated in close association with other domestic objects, as metallic oxides from these have coloured some areas of its surface (if the stone is re-polished the surface colour is usually only skin deep). During the 19th century these jades were very popular in China 3nd were manufactured and burnt intentionally in furnaces, to supply the demand for this extraordinary material. The vase stands 8.5cm tall, and varies in thickness from 1.5mm to 2.5mm. Photograph C.R. Cavey

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Vanadian grossular garnet (tsavorite) from Pakistan Brian Jackson, FGA

National Museums of Scotland, Chambers Street, Edinburgh EH1 1JF

Abstract Colour and chemistry Faceted vanadian grossular garnets from Swat, The overall colour to the eye is one of rich vivid Pakistan make exquisite gems. Though small they have greens with no apparent yellow component. Even a strong 'emerald green' colour attributed to vanadium. the smallest stones, 0.02ct, display a strong depth The physical properties and chemistry are similar to of colour. vanadian grossular garnets from East Africa: n 1.743, D The analyses presented in Table 1 were carried 3.640; SiO2 38.17, TiO2 0.44, A12O3 18.33, Fe2O3 out on a Microscan V electron probe microanal- 0.04, V2O3 4.60, MnO 0.29, Cr2O3 0.00, MgO 0.10, yser operating at an accelerating potential of 20kV CaO 36.52, Na2O 0.00, Total 98.05 (goldmanite with a probe current of 30 nanoamps. Standards 12.83%, grossular 86.08%, others minor). Inclusions used in calibration were as follows:- wollastonite include graphite, wollastonite, mica, zircon negative for silicon and calcium, jadeite for sodium, corun inclusions. dum for aluminium, periclase for magnesium, and rutile for titanium; other elements (vanadium, Preamble chromium, manganese and iron) were calibrated Tsavorite is the name given to the green to against pure metals. slightly yellowish-green variety of grossular garnet Surprisingly, even given the difficulty in esti (Stockton et al., 1985). 'Emerald green' tsavorite, mating chromium because of VKß and CrKoc from African sources, have been known since the overlap, chromium is believed to be absent or in late 1960's. The cause of colour in these garnets quantities below the resolution of peak overlap. has been variously assigned to chromium and/or Cr203 concentration based on the calculated lim vanadium: the colouring agents being locality spe its of detection has a maximum value of 0.05% cific. Green vanadium-rich grossular garnets from though any Cr203 presence is likely to be even less Kenya engendered a great deal of interest and than this. Studies of the effect of weight %Cr203 much has been written about them. In contrast on the % of green coloration trends (Manson et the vanadian 'emerald' green tsavorites from al. 1982) indicated that Cr203, despite two excep Pakistan, even though equally attractive, have tions, in amounts of less than 0.05% contributed receive little gemmological attention presumably to no more than 35% of the green coloration. On because they are less abundant and generally the other hand V203 concentrations above 2% smaller. contribute over 80% to the green coloration trend. Anderson (1966) described transparent green With V203 concentrations averaging 4.52% the grossular sent from Pakistan in the hope that they major, if not sole, influence on colour is therefore might be emerald. These, he states, were similar clearly vanadium. The fact that no colour change to a specimen he had examined a year before and was observed through the Chelsea Colour Filter all specimens showed a chromium absorption reinforces this view. spectrum. Tsavorite, from the Swat area of north No significant chemical zonation was detected ern Pakistan, has been recorded, though not in in either sample though the relationship between detail* (O'Donoghue pers comm.). the proportions of V203 and A1203 indicated that This study is based on a parcel of 25 cut stones, vanadium was replacing aluminium in the ideal weighing 2.5ct, from the Swat area. grossular formula Ca3Al2(Si04)3 giving the gen eral formula Ca3(Al,V,Fe)2(Si04)3 : Table l.

*Green grossular has been found in graphitic schists in Jambil area of Swat, near Koy in Malakand Agency and near Targhao in Bajaur Agency. Physical properties The Jambil garnets are of excellent green colour though very small. The optical and specific gravity properties of

68 '-< Q. ... 1:1 1'1 1:1 .... III III III ~ ., CT '" 1'1 ..., III :-: III Table - 1: Analyse- s of green vanadian ~ ~: IIlIJll rlJQ ? 9 ... III :;>'" ... "'1'1 ~ Q Q e..1'1 '" '" 1'1 "',<: ... 5 ~ ~ grossular garnetIJll s from Swat, Pakistan.

^ (S^-^ootNrooot^-or^ 15 4.27 0.00 0.32 0.09 0.05 odöooÖTroöövdöo0.00 d 18.66 38.21 36.71 ro i—i co ON98.75

_„ (^VÇC^V0

Q ft TT -H p H

r^^ï (NvOrH^Ol^OQOmOiO § ON S> 1975)

tQ Ü 12 ^^rûOOXMOHooooo w i-H g 0.46 0.30 0.10 0.06 0.00 3.87 Taveta 18.81 38.42 36.83 ON CO -H C<)ON 98.85 -* 1J ^ W (9-15)

O?Pakistan -Û 5 2

ja ?? '£Wiebel, H (Taita 11

S S OO^FvOOrf(NOrHVOOri- S ^& 0.00 0.00 4.41 0.46 0.11 0.05 0.00 Valley, 18.67 36.61 37.81 98.41

^CO-Sample H COON > _g J "S3 "c5 13 Lualenyi Swat (Gubelin 10 0.00 0.30 0.29 4.38 0.43 0.10 0.04 ooöodÖTfööövööo0.00 o o -, o 18.71 36.44 38.41 98.81 from CO -H CO ON C from ^ C

(U (Ü (D ."S K> .tS «3 u * Kenya u -- (Ncor-ioo-HOONOoo^o o - o y 4.60 0.05 0.00 0.31 0.00 0.43 OOÖOOOTt-'ÖOÖMDOO0.09 O 5 fi $ Ë 18.47 tsavorite tsavorite 36.28 38.22 fO-H f ^ -->-. fi molecular ^r^^-ooor^roo-Hvooo o <£ ^ as

or-r-r-ror-o-Hvoooc 4.93 0.11 oôdoodt0.07 ' dddvoo'o0.00 ô _ 36.66 38.00 98.68 c) ( (a) (b) ^ ^ ^ ^ S S 2 _>^^____>} } } ^}

°? »O5 ^t^(NOO(NOOOOO 6 7 N 4.69 0.29 0.27 0.04 0.00 0.00 0.00 0.45 0.47 0.09 (1-8)

-H oodoöd^ddd*ddo18.29 18.17 d 38.42 98.99 ^-^ r

£- ONCOTtuosoooooNioooN w ( ^.^^^^pr^tOrHp-H p(N^oqwnpON 1.70 1.53 1.81 0.74 0.02 0.00 0.43 0.50 0.10 CT+ -HTt^-OlO

vo^tcoinroi-ioovoooc ^ OLooinooNunooo-^ »o o -H —1 > 10 H H 00 10 o w 00 10 H o 1.55 1.82 4.53 0.19 0.31 0.25 0.50 0.44 0.05 0.00 0.10 0.00 0.00 3.30 0.75 0.10 9.68

hdood^'dddodoo ^ oööööcnöööioöo"0.05 N d o vo H H d o\ 18.63 20.90 38.70 37.96 38.19 36.56 98.58 00.55 00.00 35.10 99.84 86.31 00.10 m-H m ON CO (N * CO ON O O 00 O

r-rOTfiooONOON-Hort 2 0.29 4.56 ooooooTtocoooo0.43 0.05 0.00 0.09 0.00 o ^ rHT^-ioo'ooco-H'oor^ o-nomvoooo (a)

00 18.54 38.17 36.61 98.74 4.52 0.44 0.05 0.30 0.10 0.00 ^ ^ °^ oôdoodt'dddvodo000 o d o o d o o IN' 18.51 12.83 00.13 38.17 36.62 98.71 00.00 00.60 00.00 00.35 m 1—1 m ON OOOOOOO-86.08 H

m^m^tooNOOcNoio ^H r^ri-mo^O(NOrHiooo 4.60 0.29 r»' dMOTtddood0.44 0.04 0.00 0.10 «0.00 flS 18.33 37.73 36.52 m ri fO ON9B.05 O (U W (U (U u C fi 'fi •ti •'— J3 '5 ^ S > "g 's o J3 12 g - ^ O" O" n' OcOnO« ^ ^ O O n' o" O O Q 0,13 £ -£ | o- $ g 2 pessartine Uvarovite Fe,O, MnO Fe,O, Na,O Nap V,O, V,O, MgO MnO MgO Pyrope Cr,O, CaO Cr,O, CaO SiO, Al,O, Andradite Total Total TiO, TiO, Grossular Goldmanite SiO, S Almandine Alp, J.J. Gemm.,Gemm., 1992,1992, 23,23, 22 69

TableTable 22

nn DD nn (calc)(calc) DD (calc)(calc)

GrossularGrossular 1.7341.734 3.5943.594 GoldmaniteGoldmanite 1.8321.832 3.7653.765 TsavoriteTsavorite (Swat(Swat Valley)Valley) 1.7431.743 3.6403.640 1.7351.735 3.623.62 TsavoriteTsavorite (Lualenyi)(Lualenyi) 1.7431.743 3.6103.610 grossulargrossular varyvary considerablyconsiderably asas thethe nonnon grossulargrossular withwith secondarysecondary ironiron staining.staining. ThereThere areare occasionoccasion components,components, particularlyparticularly andradite,andradite, increase.increase. TheThe allyally veryvery smallsmall platy,platy, irregularirregular toto crudelycrudely hexagohexago aboveabove analysesanalyses (Table(Table 1)1) indicateindicate thatthat thethe tsavoritetsavorite nal,nal, negativenegative gasgas filledfilled inclusions.inclusions. These,These, alongalong fromfrom SwatSwat ValleyValley hashas aa highhigh goldmanitegoldmanite withwith tinytiny dropletsdroplets whichwhich oftenoften showshow neckingnecking downdown (Ca3V2(Si04)3)(Ca3V2(Si04)3) component.component. TableTable 22 presentspresents thethe features,features, areare characteristicallycharacteristically arrangedarranged inin wispywispy calculatedcalculated valuesvalues ofof refractiverefractive indexindex andand specificspecific veils.veils. ThereThere areare alsoalso aa considerableconsiderable numbernumber ofof veryvery gravitygravity forfor endend membermember grossulargrossular (Deer(Deer etet smallsmall mineralmineral particlesparticles includedincluded inin mostmost stones;stones; al.,1982)a/.,1982) andand goldmanitegoldmanite (Strens,R.G.J.,(Strens,R.G.J., 1965)1965) thosethose anisotropicanisotropic crystallitescrystallites withwith highhigh reliefrelief andand togethertogether withwith thethe observedobserved andand calculatedcalculated meanmean surroundedsurrounded byby tensiontension haloeshaloes areare thoughtthought toto bebe valuesvalues forfor SwatSwat ValleyValley andand observedobserved valuesvalues forfor zircons,zircons, thethe remainder,remainder, asas yetyet unidentified,unidentified, oftenoften Lualenyi,Lualenyi, KenyaKenya (O'Donoghue,(O'Donoghue, M.,M.,1988 1988)) tsatsa formingforming darkdark spottedspotted wispywispy trails.trails. TheThe latterlatter maymay vorite.vorite. bebe duedue toto smallsmall negativenegative inclusions,inclusions, thethe wallswalls ofof whichwhich havehave beenbeen coatedcoated withwith secondarysecondary material.material. AbsorptionAbsorption spectrumspectrum SlightlySlightly roundedrounded hexagonalhexagonal platyplaty inclusionsinclusions of,of, TheThe absorptionabsorption spectraspectra ofof tsavoritestsavorites varyvary withwith presumably,presumably, graphitegraphite areare common.common. TheseThese occuroccur asas thethe colouringcolouring agent.agent. ThoseThose tsavoritestsavorites colouredcoloured byby blackblack opaqueopaque crystalscrystals andand aggregatedaggregated crystalcrystal chromiumchromium cancan showshow aa doubletdoublet atat 697mn697mn withwith massesmasses andand tendtend toto occuroccur inin swathesswathes withwith aa highhigh weakerweaker lineslines atat 660nm660nm andand 630nm630nm andand diffusediffuse degreedegree ofof preferentialpreferential alignmentalignment thoughthough isolatedisolated bandsbands nearnear 605nm605nm andand 505nm:505nm: thesethese areare oftenoften crystalscrystals areare notnot uncommonuncommon (Figure(Figure 1).1). MinorMinor difficultdifficult toto observe.observe. leachingleaching ofof thethe graphitegraphite andand subsequentsubsequent replacereplace VanadianVanadian tsavoritestsavorites onon thethe otherother handhand rarelyrarely mentment withwith secondarysecondary ironiron oxidesoxides givesgives riserise toto showshow anythinganything otherother thanthan generalgeneral absorptionabsorption ofof brownbrown andand reddish-brownreddish-brown roundedrounded hexagonalhexagonal thethe farfar blueblue andand violetviolet beginningbeginning atat aboutabout 460nm.460nm. patches.patches. InIn additionaddition toto thisthis somesome veryvery faintfaint diffusediffuse absorpabsorp HexagonalHexagonal andand rectangularrectangular columnarcolumnar inclusionsinclusions tiontion ofof thethe red/orangered/orange andand yellowyellow waswas observedobserved inin withwith lowlow reliefrelief andand nono evidenceevidence ofof extinctionextinction areare thethe SwatSwat ValleyValley material.material. thoughtthought toto bebe negativenegative crystalscrystals formedformed byby thethe leachingleaching ofof thethe originaloriginal materialmaterial andand subsequentsubsequent InclusionsInclusions coatingcoating ofof thethe cavitycavity wallswalls withwith secondarysecondary stainingstaining MostMost stonesstones showshow fracturingfracturing toto varyingvarying degreesdegrees (Figure(Figure 2).2). TheseThese areare similarsimilar toto thethe soso calledcalled corcor somesome ofof whichwhich hashas beenbeen partiallypartially healedhealed oror filledfilled rosionrosion tubestubes foundfound inin EastEast AfricanAfrican greengreen vanadianvanadian

Fig.Fig. 1 1 AlignedAligned roundedrounded platesplates ofof graphitegraphite withwith ironiron stainingstaining andand minorminor Fig.2Fig.2 ElongatedElongated negativenegative inclusionsinclusions (gemstone(gemstone isis immersedimmersed inin didi- mica.mica. iodomethane)iodomèthane) 70 J. Gemm., 1992, 23, 2

grossular garnets. Occasionally small thin plates of gneiss in East Africa and graphitic schist in mica are seen. During microprobe analysis an Pakistan. inclusion was encountered that gave the following analysis (Table 3). Summary Faceted vanadian grossular garnets from Table 3: Microprobe analysis of an Pakistan make exquisite gems. Though small they inclusion in vanadian grossular garnet from have a strong 'emerald green' colour attributed to Swat, Pakistan, compared with wollastonite the high vanadium content (4.60%). The proper polymorphs. ties and inclusions are similar to vanadian grossu lar garnets from East Africa. mineral wollastonite inclusion -IT -7T -2M Acknowledgements I am most grateful to P.G. Hill, Geology Dept., SiO2 51.46 50.57 51.73 50.42 Edinburgh University, for undertaking the micro- TiO2 00.00 00.16 00.00 00.01 probe analyses. A12O3 00.08 00.33 00.00 00.00 Fe2O3 00.00 03.09 00.00 00.00 References Anderson, B. W., 1966. Transparent green grossular - a new gem variety; V2O3 00.00 00.00 00.00 00.00 Cr O 00.00 00.00 00.00 00.00 together with observations on translucent grossular and idocrase. 2 3 Journal of Gemmology, X, 4, 113-9 MnO 00.10 01.94 00.00 00.16 Deer, W. A., Howie, R. A., Zussman, J., 1982. Rock-forming Minerals. - MgO 00.06 00.42 00.00 00.02 2nd ed., Vol. 1A: Orthosilicates. Longman Group Ltd, England. CaO 48.27 43.65 48.30 48.65 Gubelin, E. J., Weibel, M., 1975. Green vanadium grossular garnet from Lualenyi, near Voi, Kenya. Lapidary Journal, May. 29, 2, 402-26. Na2O 00.00 00.14 00.00 00.01 Key, R. M., Hill, P. G., 1989. Further evidence for the controls on the Total 99.97 100.25 100.03 99.29 growth of vanadium grossular garnets in Kenya. Journal of Gemmology, XXI, 7, 412-22. Manson, D. V., Stockton, C. M., 1982. Gem -quality grossular garnets. Gems and Gemology, XVIII, Winter, 204-13. On the basis of the analysis and a subsequent O'Donoghue, M., 1988. Gemstones. Chapman and Hall, London, England. match using Minident-PC (A computer program Stockton, C. M., Manson, D. V., 1985. A proposed new classification for mineral identification) the inclusion is thought for gem quality garnets. Gems and Gemology, XXI, Winter, 205-18. to be one of the wollastonite polymorphs. Strens, R. G. J., 1965. Synthesis and properties of calcium vanadium The inclusions in tsavorite from Swat Valley are garnet (goldmanite). Amer. Mineral. 50, 260. very similar to the inclusions seen in tsavorite from East Africa. This reflects the comparable geologi cal environment in which they occur: graphitic [Manuscript received 3 October 1991.] J. Gemm., 1992, 23,2 71

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AnAn examinationexamination ofof 'Aqua'Aqua Aura'Aura' enhancedenhanced fashionedfashioned gemsgems Robert C.C. Kammerling and John 1.I. KoivulaKoivula GemologicalGemological InstitutInstitutee ofof AmericaAmerica,, SantaSanta MonicaMonica,, CaliforniCaliforniaa 90404,90404, USAUSA

AbstracAbstractt This article reports on the background and gemmogemmological logical propertiesproperties ooff facetedfaceted quartzquartz andand topatopazz gemsgems enhancedenhanced bbyy ththee 'Aqua'Aqua AuraAura'' processprocess.. ThisThis treatmenttreatment involveinvolvess thethe depositiodepositionn ofof a fine surfacesurface layelayerr ooff goldgold oonn the fashioned stones.stones.

IntroductionIntroduction TheThe authorsauthors havehave reportedreported previouslypreviously iinn thethe gemmologicalgemmological literatureliterature onon 'Aqua'Aqua Aura'Aura' quartz,quartz, singlesingle crystalscrystals andand crystalcrystal clustersclusters ofof colourlesscolourless quartquartzz whichwhich hahadd a thinthin filmfilm ofof golgoldd appliedapplied toto theirtheir external,external, naturalnatural surfaces.surfaces. TheseThese treatedtreated Fig.Fig. 1.1. TwTwoo facetedfaceted rocrockk crystalcrystal quartzquartz gemsgems priopriorr ttoo treatmentreatmentt bbyy thethe specimensspecimens displayeddisplayed botbothh ththee blueblue toto greenishgreenish- 'Aqua'Aqua Aura'Aura' process.process. Photo by Robert Weldon, Gemological InstituteInstitute blubluee transmissiontransmission coloucolourr ofof thethe golgoldd asas wellwell aass a ofa/America. America. thin-filmthin-film,, superficialsuperficial iridescenciridescencee (Koivula(Koivula andand Kammerling,Kammerling, 1988;1988; KammerlingKammerling andand Koivula,Koivula, FigFig.. 22.. ThesThesee foufourr facetedfaceted gemgemss havehave alalll beenbeen treatetreatedd byby thethe 'Aqua'Aqua Aura'Aura' 1989).1989). process.process. TheThe twtwoo inin thethe centrecentre areare quanz,quartz, shownshown iinn theitheirr prepre- treatmenttreatment statstatee inin FigurFiguree 11;; ththee twtwoo outeouterr specimenspecimenss areare topaz.topaz. SubsequentSubsequent toto thethe publicatiopublicationn ofof thosthosee reports,reports, Photo by Robert Weldon, Gemological InstituteInstitute ofofAmerica. America. ththee authorauthorss contactedcontacted ththee vendor,vendor, MrMr BobBob JacksonJackson

Fig. 3. The two faceted 'prisms' and pear-shape brilliant are all quartz gems treated by the 'Aqua Aura' process. Photo by Maha Smith, Gemological Institute of America. of Renton, Washington, who agreed to attempt treatment of some faceted stones for us on an experimental basis. Submitted for this purpose were two each colourless quartz (Figure 1), beryl, synthetic cubic zirconia and topaz. Mr Jackson later returned the successfully treated faceted quartz gems which had taken the treatment (Figure 2); also returned were the unsuccessfully treated cubic zirconia and topaz, plus fragments of the beryls. According to Mr Jackson, at that time only the quartz gems had taken the treatment and the beryls had 'exploded' (the latter, we surmise, may have been due to fluid inclusions which rup tured during treatment). Mr Jackson indicated, Fig. 4. Note the large colourless area on this treated quartz gem where however, that these were some of the first faceted there is no surface treatment Magnified 4x. Diffused transmitted light. Photomicrograph by John I. Koivula, Gemological Institute of stones they had attempted to have treated with America. this process (B. Jackson, pers. comm.). Thus, suc cessful treatment of gems other than quartz was Fig. 5.The apparent body colour and superficial iridescence are both noticeable in these three faceted 'Aqua Aura'-treated topazes. not ruled out. Photo by Maha Smith, Gemological Institute of America. In the spring of 1989 a report in a US lapidary hobbyist magazine shed further light on this enhancement method (Hadley, 1989a). According to the report, the process was devel oped by Messrs. Bill McKnight and Tom Stecher of Vision Industries, Lynnwood, Washington. A second report appearing four months later in the same publication indicated that faceted gems were also being treated (Hadley, 1989b). This treating of faceted stones is now taking place on a commercial basis. In the autumn of 1989 we obtained two fashioned pieces at a gem show in Santa Monica from International Crystal 74 J. Gemm., 1992, 23, 2

Company, Inc., of Seattle, Washington. These was contacted for further information. In were quartz that had been fashioned into hexago response, Mr Johnathan J. Parentice of TransGem nal 'prisms' with pyramidal terminations (Figure informed us that they were soon to begin market 3). Then, at a Los Angeles gem show in ing this material nationwide and that some 10,000 November 1989 we first saw 'Aqua Aura' treated carats were being submitted for enhancement in faceted topaz set in silver pendants. The vendor, December. Mr Parentice also kindly provided us TransGem Corporation of West Bend, Wisconsin, with several samples for our examination.

Gemmological Properties

Quartz:The quartz gems examined Topaz: The treated topaz gems examined gem gemmologically consisted of a 0.70 ct pear-shape mologically consisted of eleven faceted stones sup brilliant cut supplied by TransGem and the two plied by TransGem. These included two oval bril faceted 'prisms' (16.63 and 18.18 ct) obtained liants of 2.12 and 2.21 ct and nine pear-shape from International Crystal Company (again, see brilliants ranging from 0.71 to 2.19 ct (again, see Figure 3). Figure 2; also, Figure 5).

Table 1: Gemmological proporties of'Aqua Aura' treated gemstones.

Quartz Topaz

Colour Ranging from medium light to Ranging from medium light to medium dark slightly greenish-blue medium dark blue to greenish-blue; with weak to strong superficial irides in all cases the stones faced up a very cence. The pear-shape brilliant and uniform colour. They exhibited an smaller of the two 'prisms' appeared overlying weak to moderately strong quite uniform in colour; the larger iridescence that was most noticeable 'prism' displayed one large colourless on the larger stones. area (Figure 4).

Diaphaneity Transparent Transparent

Refractive Indices Readings obtained on the two 'prisms' Alpha = 1.610, +/- 0.001; beta were somewhat vague at 1.542-1.550 = 1.614, - 0.001; gamma= 1.620, - while the pear-shape stone gave simi 0.001; birefringence 0.009-0.010 . larly somewhat ill-defined readings at 1.543-1.551. Birefringence on all three specimens was 0.008. All read ings taken with a Duplex II refractometer and near-sodium equivalent light source.

Optic Character All three specimens displayed 'bull's- Biaxial optical interference figures eye' uniaxial optical interference fig were resolved on nine of the eleven ures between crossed polaroids and stones; all eleven plotted biaxial pos plotted uniaxial positive on the refrac- itive on the refractometer. tometer.

Pleochroism None noted when examined with a None noted when examined with a calcite dichroscope. calcite dichroscope. J. Gemm., 1992, 23, 2 75

Quartz Topaz

Ultraviolet All three specimens were inert to both All eleven stones were inert to both Fluorescence long- and short- wave radiation; there long- and short- wave radiation; was no phosphorescence. there was no phosphorescence.

Chelsea Filter Inert (appeared brownish-green). Inert (appeared brownish-green to Reaction green).

Absorption Spectra No distinct features noted when No distinct features noted when examined with either a Beck prism examined with either a prism or spectroscope or a DIS CAN digital- diffraction grating unit. readout diffraction grating unit.

Specific Gravity All three stones sank very slowly when The specific gravity was determined immersed in a solution of methylene on two of the larger stones using the iodide and benzyl benzoate calibrated hydrostatic weighing method. This to S G 2.67. The S G was thus esti produced values of 3.58 for both mated to be approximately 2.70. stones.

Magnification tip of a thermal reaction tester, this produced no Examination using a stereoscopic binocular noticeable effect on the treatment later even when microscope revealed diagnostic features of the the tip was a bright reddish orange. Furthermore 'Aqua Aura' enhancement of faceted gems. When a number 6 Mohs hardness point failed to scratch examined with diffused, direct transmitted light, an 'Aqua Aura' faceted quartz gem and a number all of the faceted specimens— both topaz and 7 Mohs hardness point similarly had no apparent quartz exhibited one or more of the following fea effect on one of the enhanced topazes. However, tures: (1) diffused, dark outlining of some facet subsequent testing with a buffing wheel and jew junctions (Figure 6); (2) white-appearing facet eller's rouge—the kind of abrasive action a stone junctions where either the treatment did not 'take' might face when prongs are buffed—resulted in the or where it had been abraded away (Figure 7); (3) removal of some of the gold coating from stones a combination of fine white-appearing facet junc where they came in contact with the polishing tions immediately bordered on either side by wheel. The fact that normal polishing in the slightly dark blue outlining; (4) irregular, minute, course of jewellery manufacture or repair will random white-appearing abrasions on facet junc remove some of the coating should be taken into tions and/or surface pits, scratches and areas consideration by anyone working with 'Aqua where the treatment did not take on facet surfaces Aura'-treated gems. Stone repolishing or recutting (Figure 8); (5) irregular blue coloration on some also would be expected to remove the treatment facets and slight iridescence visible even in dif layer (Koivula and Kammerling, 1991). fused transmitted light (Figure 9); areas of no colour on some facets (again, see Figure 8). One Discussion and Conclusions of the pearshape topazes exhibited an area of The more greenish-blue specimens of 'Aqua exceptionally heavy deposition near its point. Aura' treated quartz or topaz could be visually When examined in surface-reflected light under mistaken for heat-treated zircon, especially those magnification, the iridescence became very notice displaying fairly prominent iridescence, as this able on all specimens and the surface irregularities might at first glance be mistaken for dispersion. were easy to detect (Figure 10). Refractive index, birefringence and specific grav ity readings, however, would quickly help to iden Durability tify the gem materials as topaz or quartz respec Additional testing was carried out to determine tively. some of the durability characteristics of this sur While there is no natural blue single-crystal face enhancement. Both quartz and topaz speci quartz with which the 'Aqua Aura' quartz could mens were first exposed to the electrically heated be confused, it does bear a resemblance to some 76 J. Gemm., 1992, 23, 2

Fig. 6. Dark, diffused outlining of facet junctions, as exemplified by this Fig. 7. The diagnostic white-appearing facet junctions on this treated topaz, is a key feature of 'Aqua Aura' treatment of faceted gems. topaz represent areas where either the treatment did not 'take' or Magnified 6x. Diffused transmitted light. Photomicrograph by where it has been abraded away. Magnified lOx. Diffused John I. Koivula, Gemological Institute of America. transmitted light. Photomicrograph by John I. Koivula, Gemological Institute of America.

Fig. 8. This 'Aqua Aura' treated topaz exhibits characteristic irregular, minute, random white-appearing abrasions on facet junctions and surface pits and scratches on facet surfaces. Note also the colourless area at the top of the photo. Magnified 4x. Diffused transmitted light. Photomicrograph by John I. Koivula, Gemological Institute of America.

Fig. 10. When examined in surface-reflected light under magnification, Fig. 9. Several of the facets on this treated topaz display irregular blue the iridescence on this 'Aqua Aura' treated topaz becomes very coloration. Magnified 6x. Diffused transmitted light. noticeable and the surface irregularities are easy to detect. Photomicrograph by John I. Koivula, Gemological Institute of Magnified 12x. Photomicrograph by John I. Koivula, Gemological America. Institute of America. J. Gemm., 1992, 23, 2 77

cobalt-doped blue synthetic quartz. In this Acknowledgements instance Chelsea filter reaction and absorption The authors would like to thank Mr Bob spectrum would make the separation, as the syn Jackson of Renton, Washington, for treating and thetic quartz appears pinkish through the filter and providing materials; and Mr Johnathan J. exhibits cobalt absorption (Liddicoat, 1989). The Parentice of TransGem Corporation, West Bend, 'Aqua Aura' topaz might easily be mistaken ini Wisconsin, for providing treated gems and infor tially for the irradiated blue topaz which is so mation. prevalent in today's gem market; Mr Parentice did in fact acknowledge that TransGem's product References could be used as an alternative Q. Parentice, pers. Hadley, W., 1989a. 'Aqua Aura': A revolutionary enhancing process turns quartz into a rainbow! Rock & Gem, 19, 5, 48-50. comm.). In all cases, however, with both the topaz Hadley, W., 1989b. 'Aqua Aura' Chess Set. Rock & Gem, 19, 9, 68-9. and quartz gems the superficial iridescence is a Kammerling, R.C., Koivula, J.I., 1989. 'Aqua Aura' enhanced quartz strong indicator and magnification would quickly specimens. Journal of Gemmology, 21, 6, 364-7 . Kane, R.E., Kammerling, R.C., Koivula, J.I., Shigley, J.E.,Fritsch, E., reveal the 'Aqua Aura' treatment. The total 1990. The identification of blue diffusion-treated sapphires. Gems absence of pleochroism might also draw suspicion. & Gemology, 26, 2, 115-33. One final point worth noting relates to two of Koivula, J.I., Kammerling, R.C., 1988. Gem News: 'Aqua Aura' quartz. Gems & Gemology, 24, 4, 251. the features seen under magnification. It struck the Koivula, J.I., Kammerling, R.C. 1991. Gem News: Faceted 'Aqua Aura' authors that both the dark concentrations of update. Gems & Gemology, 27, 2, 122. colour along facet junctions and the uneven col Liddicoat, R.T., 1989. Handbook of Gem Identification, 12 edn, 2nd oration were similar to features we have noted on revised printing, Gemological Institute of America, Santa Monica. blue diffusion-treated sapphires which are being seen with more regularity in the gem trade (Kane [Manuscript received 8 October 1990] etaU 1990). 78 J. Gemm., 1992, 23, 2

A Book Anniversary R. Keith Mitchell, FGA

Orpington, Kent

For gemmologists this is the fiftieth year of one of ruby and emerald from African locations were dealt our best and most enduring textbooks. I refer of with. The newly discovered radio-active mineral course to the late B. W Anderson's Gem Testing, first ekanite from Ceylon (Sri Lanka) was included for published by Heywood & Company under the the first time, while flesh-nucleated fresh-water slightly more limiting title Gem Testing for Jewellers cultured pearls from Japan, and other non- in 1942. nucleated ones from the coastal waters of Australia Anderson had at that time headed the London and Burma, were also discussed. Chamber of Commerce Pearl and Precious Stone The 8th edition (1971) (French and Italian 1973; Laboratory for some seventeen years and was the Spanish 1977) introduced the 'rare-earth garnets', foremost gemmologist in this country and already man-made products of laser research many of which renowned world-wide. It would have been difficult were cuttable as gems; more new synthetic emeralds to find a more suitable author for such a book, or and new jade-like massive natural garnets and one more capable of conveying his very consider chalcedonies. The most important new gem in able knowledge in an eminently readable form to cluded in this edition was the violet-blue form of the the comparatively unscientific reader. mineral zoisite which was named tanzanite after its That first modest hard-cover edition ran to 194 country of origin. pages with 43 illustrations, and retailed for the now The 9th edition (1980) (Japanese and Russian astonishingly low price of 7/6 in old coinage, 37.5p 1983, Italian 1984) described more innovative gems today. 2nd and 3rd editions appeared in 1943 and than any previous edition. These included synthetic '44 which were in truth simply reprints of the first turquoise, alexandrites and opals; cubic zirconia, owing to war-time restrictions on paper and other by far the most successful simulant of diamond; materials. Slocum imitation opals; new opal doublets; various 1947 saw the re-written 4th edition which ran to synthetics by processes more akin to those of 224 pages and 53 illustrations, plus a coloured nature; colour improvement by oiling, impregnat frontispiece of absorption spectra drawings as seen ing, staining and irradiation; fine green grossular through a diffraction grating instrument, which had garnets; garnets with a colour change; new sources been recommended in the earlier editions, although of fine rubies, emeralds and other gems in Africa. the text now came down firmly in favour of the Beck The Dialdex refractometer by Rayner, and the 2458 prism instrument. RIPlus which reads to 2.26, and other instruments A 5th edition in 1951 (German version in 1955) involving the reflection of infrared light were de was augmented to 246 pages and 62 illustrations, scribed. And in this edition prism type spectra were and included synthetic rutile, synthetic star rubies illustrated in black and white both in the European and sapphires and added some 20 of the rarer gems 'red on the left' version, and the American 'red on to the appendix list of stones. the right' version. The 6th edition (1958) brought in synthetic That, very regrettably, was to be the last edition strontium titanate, new emerald synthetics and a prepared by Basil Anderson himself, for he died sintered spinel imitation of lapis lazuli. New identi suddenly and peacefully aged 82 in January 1984. fication techniques included immersion contrast But such a valuable and popular textbook could not photography and the crossed filter fluorescence be allowed to die with its author, and several years test, both introduced to gemmology by Anderson later Mr E.A. Jobbins, formerly Curator of Gems some years earlier. and Minerals at the Geological Museum, was asked Further types of synthetic emerald were included to produce another edition. in the 7th edition (1964), and new sources of fine The 10th and current edition (1990) ran to 389

larger pages, with 160 illustrations in black and (new colours in garnets); Pakistan (fine emeralds white (a few of which span the half century), plus and natural pink topaz); Afghanistan (kunzite) and seventy excellent colour plates which were largely a very promising range of gems from China, are the very skilled work of Mr Jobbins himself. described. It still contains a great deal of Anderson's original Over the years various of the earlier editions have and explicit text from the earlier editions, but has been translated into many languages. In view of the been skilfully and compatibly updated and ex vastly enhanced compilation of valuable gemmolo- panded to give new chapters on the manufacture of gical facts now within the covers of this tenth synthetics and imitations, and on gemstone en edition, I feel there is a good case for further hancement, while the existing chapter on the detec translations into those and other languages to bring tion of synthetics, imitations and composite stones students in foreign countries up to date in the has been rearranged, and in part re-written. gemmological scene. Faceted yellow synthetic diamonds are dealt with Basil Anderson, the enthusiast and pioneer of so and new reflectivity and conductivity meters to much of our trade science, has passed on in the combat diamond simulants are described. The fullness of time, but this splendid textbook remains artificial production of fancy colours in diamond by as a best-selling tribute to his remarkable genius various types of irradiation is discussed and ways to and life-long love of gems, and may well do so for identify such treatment are given. many more editions and years to come. Many new sources of gems from such widely differing places as Brazil (fine alexandrites); Niger ia (sapphire and aquamarine); Kenya/Tanzania [Manuscript received January 1992.] 8080 J.J. Gemm.,Gemm., 1992,23,21992, 23, 2

RadioactiveRadioactive glassglass imitationimitation emeraldsemeralds andand anan unusualunusual VerneuilVerneuil syntheticsynthetic rubrubyy ].J. M.M. Duroc-Danner, FGA, FGA, GG GG

Geneva,Geneva, SwitzerlandSwitzerland

AbstractAbstract TheirTheir specificspecific gravitygravity wawass obtainedobtained byby hydrostahydrosta RadioactivitRadioactivityy inin glassglass substitutessubstitutes hashas beenbeen reportedreported tictic weighingweighing ofof thethe stonesstones inin distilleddistilled waterwater usingusing a recently C'(1,2 2).). InducedInduced fingerprintsfingerprints inin Verneuil synthesynthetics MettlerMettler electronicelectronic PPLL 300C300C caratcarat scale,scale, andand thethe ticsare are not not unknown, unknown, but but in in a a lamellar-twinned lamellar-twinned synthesynthetic stonesstones werewere foundfound toto havehave a specificspecific gravitygravity ofof 3.3.75 7544 tic theythey cancan bebe eveneven moremore deceiving.deceiving. ThisThis articlearticle reportsreports andand 3.767.3.767. onon thethe useuse ofof treatmentstreatments.t too alteralter thethe appearanceappearance anandd TheThe fluorescencefluorescence waswas examinedexamined withwith a MultispecMultispec consequentlyconsequently toto makemake a straightforwardstraightforward identificationidentification combinedcombined LW/SWLW/SW unit,unit, andand bothboth stonesstones showedshowed more difficult.difficult. underunder long-waveslong-waves chalkychalky orange;orange; andand underunder shortshort- RadioactiveRadioactive glassglass imitationimitation emeraldsemeralds waveswaves chalkychalky green.green. A pairpair ofof emerald-cutemerald-cut greengreen stonesstones thatthat TheThe absorptionabsorption spectrumspectrum seenseen throughthrough a GemGem approachedapproached thethe finestfinest emeraldemerald coloucolourr werewere receivedreceived BeckBeck SpectroscopeSpectroscope UnitUnit showedshowed a strongstrong absorpabsorp recentlyrecently byby thethe authorauthor forfor identification.identification. tiontion 400-440400-440 nm,nm, a setset ofof twotwo lineslines centredcentred atat 460460,, Approx.Approx. measurementsmeasurements andand weightweight 470470 nm,nm, andand a strongstrong absorptionabsorption 600-700600-700 nm.nm. 14.6914.69 x 1l.9711.97 x 7.60mm,7.60mm, 12.4612.46 caratscarats TheThe twotwo stonesstones werewere identifiedidentified asas glass,glass, andand 14.9914.99 x 1l.9411.94 x 6.81mm,6.81mm, 1l.0711.07 caratscarats accordingaccording toto Bannister'sBannister's graphgraph couldcould bbee eithereither leadlead 3 UndeUnderr a BauschBausch & LombLomb MarkMark V GemoliteGemolite glassesglasses oror bariubariumm glasseglassess e).( ). binoculabinocularr microscopmicroscopee usingusing dardarkk field illumination,illumination, A routineroutine testtest performeperformedd byby thethe authorauthor isis toto thethe stonesstones werweree foundfound toto containcontain skeinsskeins ofof largelarge andand submitsubmit allall stonesstones hehe receivesreceives toto a GeigerGeiger counter.counter. TToo smallsmall gasgas bubbles,bubbles, whichwhich withwith a lOx10 x lenslens couldcould hishis greatgreat surprise,surprise, whenwhen thethe glassglass imitationimitation emeraldsemeralds easilyeasily havehave beenbeen mistakemistakenn forfor naturalnatural fluidfluid incluinclu werewere submittedsubmitted toto a SolarSolar ElectronicsElectronics RadiationRadiation sionssions (Figures(Figures 1 andand 2).2) . AlertAlert MonitorMonitor 4,4, theythey werewere foundfound toto bebe radioactiveradioactive TheThe refractiverefractive indexindex determinationdetermination carriedcarried outout (Figure(Figure 3)3).. usingusing a RaynerRayner DialdexDialdex refractometerrefractometer andand AlthoughAlthough thethe radioactivityradioactivity recordedrecorded showedshowed 0.080.08 monochromaticmonochromatic sodiumsodium lightlight gavegave l.635.1.635. UnderUnder thethe mR/hmR/h ifif onlyonly oneone glassglass resterestedd onon thethe countercounter windowwindow polariscope,polariscope, thethe stonesstones confirmedconfirmed theirtheir opticoptic charchar ofof thethe MonitorMonitor 4,4, itit recordsrecords 0.120.12 mR/hmR/h whenwhen thethe twotwo acteracter toto bbee isotropic.isotropic. glassesglasses werewere testedtested togethertogether underunder thethe samesame condi-condi-

Fig.Fig. 11.. SkeinsSkeins ofof largelarge andand smallsmall gasgas bubblesbubbles foundfound asas FigFig.. 2.2. A similarsimilar typtypee ofof inclusioninclusion showingshowing a largelarge andand wellwell inclusioninclusionss inin thethe radioactiveradioactive glassglass imitationimitation emerald.emerald. formedformed gasgas bubble.bubble.

tions (Figure 4). It should be noted here that background levels indicate 0.00 mR/h to 0.02 mR/h. This means that these two glasses when tested together were registering up to twelve times back ground levels.

Discussion Unfortunately, the author was unable to perform a qualitative chemical analysis to determine the heavy elements contained in these glasses (lead, iron, uranium, etc.), so the question remains open as to their composition. According to the gemmological data, the author believes that these glasses could be lead glasses containing uranium and iron. This would be an answer both for the radioactivity observed and for the iron absorption spectrum recorded. Anyway, this is purely of an academic interest only. The important point is to be aware that since many gemstones are irradiated, it is wise to check these routinely with a Geiger counter for radioactivity. It is also important to realize that as shown in Figure 3, the radioactivity increases with quantity. In other words, if a sole 'weakly' radioactive stone presents 'little' danger, a set composed of these would

Fig. 3. The radioactivity of 0.08 mR/h recorded by Solar Electronics Radiation Alert Monitor 4, for a single glass imitation emerald.

Fig. 4. The radioactivity of 0.12 mR/h recorded under the same conditions, but for the pair of glass imitation emeralds. certainly be of 'some' risk. Lastly, considering these glasses formed a pair, what would be the consequences if these were set as ear-clips, worn daily near the lymphatic glands. The question as to why simulate emeralds with radioactive glass finds no positive answer, for there exist very good imitations with colouring agents other than uranium.

A Verneuil synthetic ruby showing polysynthetic twin lamellae and induced fingerprints Among the interesting stones held by a private collector was a 6.84 ct cushion-shaped red stone that was bought some 15-20 years ago as a ruby. Although the owner had some doubts concerning the authenticity of the stone, it is only recently that he decided to have it tested. Routine gemmological tests: refractive indices, absorption spectrum and specific gravity, con firmed the stone to be corundum, variety ruby. The next step was to tell whether the ruby was natural or synthetic. The stone measured approx. 11.15 x 9.76 x 6.20mm, was surprisingly well proportioned with a symmetrical pavilion. 82 J. Gemm., 1992, 23, 2

Fig. 5. Fractures and fingerprints as they appeared under the Fig. 6. Induced fingerprints showing a dendritic-like pattern, microscope, in the Verneuil synthetic ruby. observed under the microscope in the Verneuil ruby.

The visual appearance revealed many internal Straight and parallel twinning lines were also fractures, with some breaking the surface. Under a present in this stone (Figures 8 and 9). 10 x lens, numerous 'feathers', some with healed It should be noted here that with crystal inclu 'fingerprint' patterns could be seen. Since 'finger sions, healing planes filled with liquid drops and prints' are also encountered in many modern soph zonal effects in straight lines, polysynthetic twin isticated synthetics (Chatham, Kashan, Knischka, lamellae are regarded as one of the characteristics of Ramaura, etc.), and can be induced in Verneuil genuine corundum. If this twinning occurs fre synthetics (4), these had to be closely examined to quently in rubies (Thai, East Africa), it is less so in see if they contained liquid and gas-filled voids, like sapphires (Pailin, East Africa). In synthetic Ver the genuine corundums, or were filled with solid neuil corundum, and due to the fact that a 'boule' flux, like the synthetics. consists in general of a monocrystal, this type of Observed under the microscope, the fractures twinning is encountered rather exceptionally. To and the 'fingerprints' were immediately seen this day, out of hundreds of synthetic Verneuil (Figure 5). With higher magnification, the filled corundums observed by the author, only two 5 healed fractures showed a dendritic-like pattern, showed this type of twinning ( ). probably due to the crystallization of the low Prominent tightly curved structure lines, similar temperature melt (?) induced in them (Figure 6). to the grooves seen on a gramophone record, were Another deceiving inclusion observed under high present as could be expected in a flame-fusion magnification consisted of a small dense 'nest' of synthetic ruby (Figure 10). very fine gas bubbles (Figure 7). These found lying Although it was evident that this was a synthetic between internal strain fractures could incorrectly flame-fusion Verneuil ruby, it was decided for have been taken for exsolved rutile needles. effectiveness to perform an ultimate test.

Fig. 7. Small dense 'nest' of very fine gas bubbles lying Fig. 8. Straight and parallel twinning striations as they between internal strain fractures. Observed under the appeared under the microscope, in the synthetic Ver microscope in dark-field illumination, in the synthetic neuil ruby. Verneuil ruby. J.J. Gemm.,Gemm., 1992,1992, 23,23, 2 8383

Fig.Fig. 9.9. DetailedDetailed viewview ofof a polysyntheticpolysynthetic twintwin lamellae,lamellae, Fig.Fig. 10.10. CurvedCurved growtgrowthh lineslines andand ththee fractures,fractures, observedobserved underunder observedobserved underunder thethe microscope.microscope. NoticNOlicee thethe fracturefracture thethe microscopemicroscope inin thethe syntheticsynthetic VerneuilVerneuil ruby.ruby. breakingbreaking thethe surfacesurface ofof thethe syntheticsynthetic yerneuilVerneuil ruby.ruby. Crowningshield,Crowningshield, R.,R., 1990.1990. GemGem TradTradee LabLab NotesNotes.. RadioactiveRadioactive glassglass egg.egg. Gems&Gems & Gemology, XXVI,XXVI, 2,155.2, 155. TheThe stonestone waswas immerseimmersedd inin methylenemethylene iodide,iodide, Webster, R.,R., 1987. 1987. Gems, Gems, Their Their Sources, Sources, Description Description and and Identification, Identi betweenbetween crossedcrossed polarspolars setset toto theirtheir darkdark position;position; 4thfication, edn. 443. 4th edn. 443. onceonce thethe opticoptic axisaxis waswas located,located, a 'PlatoTlato striation'striatum' KoivulaKoivula,, J.I.,J.I., 1983.1983. InducedInduced fingerprints.fingerprints. Gems & Gemalogy,Gemology, effect,effect, whicwhichh betraysbetrays VerneuilVerneuil syntheticssynthetics waswas XIX,XIX, 4,4, 220-7220-7.. Duroc-DannerDuroc-Danner,, J.M.,J.M., 1985.1985. PolysynthetiPolysyntheticc twintwin lamellaelamellae inin obtainedobtained (Figur(Figuree 11)11).. syntheticsynthetic VerneuiVerneuill sapphire.sapphire. Journal of Gemmology, XIX,XIX, 6,6, 479-83.479-83. DiscussionDiscussion TheThe unnaturalunnatural appearanceappearance ofof syntheticsynthetic VerneuilVerneuil [Manuscript[Manuscript receivedreceived 4 4 January January 1991.]1991. ] stonesstones thatthat areare devoiddevoid ofof inclusionsinclusions cancan bebe considerconsider Fig.Fig. 11II.. 'Plato'Plato striation'striation' obtainedobtained parallelparallel toto ththee c-axisc-axis whilewhile thethe ablyably improvedimproved bbyy thethe actact ofof 'quench-crackling~'quench-crackling', andand stonestone waswas immersedimmersed inin methylenemethylene iodideiodide betweenbetween lettinlettingg a chemicalchemical substancesubstance suchsuch asas boraxborax crystalcrystal crossedcrossed polaroidspolaroids inin theirtheir darkdark position.position. ObservedObserved inin lizelize intointo thethe crackscracks toto formform 'fingerprint-like''fingerprint-like' patpat thethe syntheticsynthetic VerneuilVerneuil ruby.ruby. ternsterns.. IfIf ththee formerformer isis anan earlyearly syntheticsynthetic VerneuilVerneuil,, likelike thethe oneone describeddescribed here,here, thenthen thethe existingexisting smallsmall groupsgroups ofof gasgas bubblesbubbles itit contains,contains, inin conjunctionconjunction withwith ththee newlynewly createdcreated environment,environment, cacann bbee misinmisin terpreted,terpreted, andand addadd toto thethe confusion.confusion. HadHad thisthis stonestone beenbeen cutcut byby anan innocentinnocent lapidary,lapidary, withwith a 'native''native' cutcut insteadinstead ofof thethe mechanicalmechanical symsym metricalmetrical cutcut thisthis stonestone showed,showed, thisthis surelysurely wouldwould havehave increasedincreased thethe possiblepossible confusion.confusion. EspeciallyEspecially iiff a jewellerjeweller camecame acrossacross thisthis stonestone onon a buyingbuying triptrip inin gemgem localities,localities, wherewhere hehe wouldwould normallynormally expectexpect toto seesee genuinegenuine stones,stones, withwith a 1010 xx lenslens asas hishis solesole equipment.equipment.

ConcludingConcluding thoughtsthoughts ForFor ththee author,author, radioactiveradioactive glassglass imitations,imitations, andand inducedinduced fingerprintsfingerprints inin synthetics,synthetics, cannotcannot bebe rere gardedgarded asas innocentinnocent imitations,imitations, oror ordinaryordinary synthesynthe tics.tics. TheyThey areare intentionallyintentionally mademade ttoo deceive,deceive, cancan bebe a threatthreat toto thethe health,health, shouldshould bebe consideredconsidered forgerforger ies,ies, andand forfor thesethese reasons,reasons, thesethese treatmentstreatments mustmust bebe disclosed.disclosed.

ReferencesReferences Nassau,Nassau, K.,K., Lewand,Lewand, E.A.,E.A., 1989.1989. MildlyMildly radioactiveradioactive rhinestonesrhinestones andand syntheticsynthetic spinel-and-glassspinel-and-glass triplets.triplets. Gems && Gemology, XXV,XXV, 4,4, 232-5232-5.. 84 J. Gemm., 1992, 23, 2

The French Connection A.E. Farn, FGA

Seaford, East Sussex

The cordial understanding engendered by Ed museum of Hove' close to Brighton and relates, ward VII's visit to Paris in 1903 was a valuable 'L'Aventure d'une aventurine'. precursor towards the Anglo-French Entente of A rough, bronze-coloured block entered trium 1904. The term 'Entente Cordiale'may equally well phantly through the main entrance. It was large and be used to describe the gemmological ties between heavy, 70cms in length, 50cms wide and of a similar the laboratories of London and Paris. Long long height. Placed in the centre of a gallery it was before CIBJO there was a strong bond of mutual mounted on a low pedestal supported on four feet assistance between these two pearl trade centres. and enclosed by wooden rails. Thus visitors could However it is not my intention to write of the see without touching and at the same time admire early days of pearl testing. Rather it is to write of one the bright spangled reflections from its uneven particular member of the Paris laboratory. I have surface. been brought to this historic pitch through leafing Alas one day some gemmologists recognized among some of the writings of Mile Dina Level. what it was. A block of sub-translucent glass with Each time I read Dina's writings I marvel afresh at inclusions of triangular copper spangles. Uncere her effervescent enthusiasm. moniously it was relegated to a position at street She served under both Georges Gôbel the first level at the entrance and labelled, 'Aventurine Glass'. director and Jean-Paul Poirot the second (present) In this account written in 1970, Dina says that it was director of the Paris laboratory. Details of her years some 15 years ago, which places it at about 1955. 'In of service, awards and presentations appear in the my early days at the laboratory I remember Basil July 1988 Journal of Gemmology (21, 3,140-1). Anderson speaking of his encounter with a local If I could liken her to any other gemmologist it museum where a large block of aventurine glass was would be Robert Webster. Both were of small imposingly displayed. Basil Anderson was living at stature, both were giants in their sphere. Dina Level that time in the nearby Sussex village of Ditchling. was an important petite person who could wax Dina's final comment on this little episode was to enthusiastic with the merest frond of moss agate, a write philosophically; 'If it is still in the same place fugitive fluorescence, a nuage of gas bubbles or the the inclement weather will tarnish it. Unfortunately watered silk reflection from a pale pink pearl. after its brilliant but ephemeral success it has to be Vivid, vivacious, volatile, Dina was truly Gallic like any other stone.' (Regrettably, from recent yet was nevertheless an anglophile. It is impossible enquiries, there no longer seems to be a display of in English to convey the personal approach she took gemmological interest.) I was informed that when describing colour, size, weight or any charac changes had taken place in the museum. This teristic of a gem. She had a sympathy and concern observation must have a familiar sound to some of for the mis-shapen, the lop-sided, the baroque and us? the broken. She talked to her gems (pierre tu vas me In an earlier article by Dina Level in the June dire quelque chose). 1970 Revue de Gemmologie she writes in retrospec Being Dina Level, 'Grande amoureuse des gem tive mood of 'Quarante ans derrière la Binoculaire', mes' she employed the intimate 'tu' rather than the 'Quarante ans d'enthousiasme', literally 40 years usual 'vous'. In the 'Revue du Gemmologie,' afg, 24, behind the binocular microscope and in italics 40 Sept 1970, pp4-6, Dina Level wrote of her 'Aven years of enthusiasm. tures dans les Musées d'Angleterre'. . She remembers her first sight of No 18 Rue de* She often conducted parties of students on tours Provence in April 1930. In the office of La Chambre of selected museums in the south east of England Syndicale des Négociants en Diamants, Perles using Newhaven as the arrival port. In a brief Fines, Pierres Précieuses et des Lapidaires there description she describes a visit to 'the charming was a wall chart. One half was printed in red

showing the rutile needles in natural rubies and hundreds of calibré sapphires using the binocular curved structures of synthetic rubies. The other microscope as: 'A diver amazed and wonderstruck half, printed in blue, depicted the straight line in these hermetically sealed waters. Fish following hexagons and chevrons of natural sapphires with each other, liquid drops in flight, waving fronds of the soft curves and bubble clouds of synthetic seaweed, phantom vessels stranded amongst the sapphires. mountains of the sea bed'. Memories and images follow in succession some Dina describes how she spent one night alone in times overlapping. She recalls the great fly-wheel the laboratory taking photo-micrographs of inclu structure looking like a ship's steering wheel of the sions and external features of some rough industrial X-ray generating set. This like London's early X-ray diamonds. Many were clean and had good crystal set only produced lauegrams. The memory of black shapes; she was entranced by the Egyptian beauty cloth-covered trays full of pearls, the subtle nuances of these 'double' pyramids, looking like the reflec and éclat completely escaping her novice's eye. tions of the pyramids in the Nile at Giza. One in The tiny hollow needle of the endoscope (shades particular captivated her; she describes one of its of Arsène Lupin), whose minute point sheltered faces as a hollow triangular engraving like a stair two mirrors thanks to which one could see a fleeting case becoming narrower and narrower as it pene ray of 'sunshine' lifting in succession the theatre trated towards the centre of the octahedron. curtains of the golden layers (conchiolin?) of natural Plunged into a new ecstasy she wanted to make pearls or the uniform snowy centres of cultured them re-live in her photo-micrographs - 'To which pearls. sleeping Pharaoh did the steps of the hollow There was another image which, whilst agreeable pyramid lead?' All equal intersections, luminous, to the eye, tortured her for a week; she vowed she'd transparent, perfect. What divine chisel cut them in never stay a week in this laboratory. It was the this adamantine block? How should they be illu density balance of gilded copper gleaming in its minated in order to transfer to a flat film the cage of glass, its pans suspended by chains and the dimensional relief seen in the lens of the micro diabolical beam of such sensitivity that to take a scope? density for her was as difficult as it was for a camel to After a long session of photography, placing film, pass through the eye of a needle. Dina repeats siting the diamonds for maximum result and aware 'When I say take a density, I wish to say attempt of the war-time shortage of good quality film she once, twice, ten times to measure the density of the was ready. The portable lamps had been placed in a same stone and to get the same result. At last I circle surrounding the camera and microscope, the succeeded and the cyclopic eye of the balance out of diamond being literally the cynosure of all. Dina its glass cage ceased to wither me every morning'. switched off the lights, but in the centre a blue- She was able at last to verify the true identity of a mauve glow was being emitted - the diamond was variety of gemstones used in tests for 'eye spotting'. phosphorescent. It seemed about 15 seconds before (In the old lab we used well established specimens the glow finally died. such as slices of innocuous indeterminate coloured She says, 'That moment was the most intense of gem material for early practice in establishing my life. Imagine the silence of the night, undetected densities by hydrostatic method.) behind the black-out curtains, impossible to go out, She pays tribute to the untiring patience of the seclusion imposed by the curfew, and the Georges Gôbel who showed her how to take photo solitude of the deserted laboratory. To wonder in graphs of inclusions and how to develop and fix her that desperate war-time atmosphere, what made negatives. Whether it is the development of a this message of hope come not from outside but negative for a print, or an enlargement, she confes from inside this solid substance, this materialization ses that she never fails to see the image appear in the of the eternity of this immaculate carbon. This gem developing dish without emotion. The action in the made from a unique element, omnipresent in every developing dish she describes 'As if it is coming thing which lives and breathes. I can at will re-live back from a vanished world and is reborn dancing in this dazzling tête à tête but I do not dwell on this the liquid depths'. memory, I lift up my eyes towards that staircase This magic fluid has a name which is fully divine to the steps to the Light'. justified (sensible); it is the révélateur (revealer) and Dina Level ends her long reminiscence saying, can be allied to the unrolling of the wrappings of 'Ah, if it was to be done again I would re-do it'. mummies. Finally the fixer which will, as the She died on 17 July 1988 at Nimes in the south of hardening element, preserve the portrait of the France - she was 85. With Basil Anderson and inclusion long after the host gem has rejoined its Robert Webster she leaves her mark in the annals of owner. Gemmology. We shall never see her like again. She describes the examination of hundreds and [Manuscript received 12 December 1991.] 86 J. Gemm, 1992, 23, 2

On the properties of meteoritic gem olivine from a pallasite from Esquel, Patagonia, Argentina Dr Ulrich Henn 1 and Andreas F. A. Becker 2

1 German Foundation for Gemstone Research, Idar-Oberstein,Germany 2 Friedrich August Becker, Idar-Oberstein, Germany

Fig.1. Pallasite plate from Esquel5 Patagonia, Argentina, and three faceted meteoritic gem olivines (largest 1.6 ct).

1. Abstract bers forsterite Mg2Si04 and fayalite Fe2Si04; The properties of faceted gem olivines (peridot) from another diadochy is present between fayalite and a stony-iron meteorite (pallasite) found at Esquel, tephroite Mn2Si04. In magnesium-rich olivines Patagonia, Argentina, are described. nickel is commonly present. The green colour is due to Fe2+ of the fayalite component. 2. Introduction Olivine as a constituent of meteorites is well Olivine is one of the common rock-forming known, and Webster (1983) mentioned speci minerals in the earth's crust with an average con mens said to be of a sufficient size and quality to tent of about 3.5%. Transparent green crystals of be suitable for cutting into gemstones. One of the gem quality olivine are generally called peridot. authors has now separated transparent green frag The most important occurrence was on the island ments from a meteorite plate from Esquel in of Zeberget (Egypt) in the Red Sea; today's com Patagonia, Argentia, and cut these into faceted mercial production is from the Mogok District of stones up to 1.60 cts (Figure 1). Upper Burma and Arizona, USA. Meteorites are fragments of celestial bodies of The minerals of the olivine group form a com the asteroid belt between Mars and Jupiter and are plete series of mixed crystals with the end-mem divided into three types: (1) iron meteorites, (2)

iron-stone meteorites and (3) stony meteorites. wt.% (= 81%forsterite) (Bank, 1986). The gem quality olivines described here originate The meteoritic olivine of the pallasite from from a type of stony-iron call pallasite, which con Esquel in Argentina has refractive indices, bire sists of a network of nickeliferous iron (iron mete fringence and density of nx=1.658-1.660, orite) with crystals of olivine about 1 square cen n y=1.671-1.673, nz=1.693-1.696, ~n=0.034 timetre in size. The meteoritic olivines are 0.037, D=3.34-3.37 g/cm', which are in the distinctly fractured, but clean cuttable parts are known range of gem olivines. present up to 5 square millimetres in size. Gemmological investigations of the physical, 3.2 Absorption spectrum chemical and microscopical properties have been The unpolarized absorption spectrum in the carried out to compare the meteoritic olivines with 300-2000 nm (33,333-5,000 cm') range (Figure sublunary gem olivines. 2) shows absorption bands ofFe 2+, which are typ ical for olivine (Runciman et al., 1973; Smith & 3. Physical properties Langer, 1982). The maxima are at 9,350, 11,490, 15,770,19,120,20,280,22,120 and 24,810 em:' 3.1. Refractive indices, birefringenceand density (1070,870,634,523,493,452 and 403 nm). Within the olivine group the values of refractive indices, birefringence and density increase linearly 4. Chemical properties with the chemical composition from forsterite to fayalite, between which there is continuous varia The results of semi-quantitative EDS-analyses tion: n,,=1.635-1.827, ny =1.651-1.869, nz=1.670 of three samples of the meteoritic olivines are 1.879, &1=0.035-0.052, D=3.22-4.39 g/cm' (Deer, listed in Table 1. The calculated composition Howie & Zussman, 1983). The values of gem characterizes the material as mixed crystals with quality olivines hitherto published in literature vary dominant contents of forsterite and distinct fay between n,,=1.640, ny =1.657, ~=1.675, &1=0.035, alite distributions. The tephroite contents are rel D=3.20 g/cm' for a nearly colourless stone from Sri atively low. These olivine compositions corre Lanka with a forsterite content of 95% (Bank, spond to the values of refractive indices, 1984) and n x= 1.670, ny= 1.688, n z= 1.706, birefringence and density given in the known cor &1=0.036, D=3.43 glcm' for a green specimen from relation diagrams for the minerals of the olivine the Eifel, Germany, with a FeD content of 16.79 group (e.g. Deer, Howie & Zussman, 1983).

Fig. 2. Unpolarized absorption spectrum of a meteoritic gem olivine in the 300-2000 nm range.

1070 I c o +'" 0. ~ o VI .0 oct:

400 600 800 1000 1200 1400 1600 1800 2000

Wavelength (nm) 8888 J.J. Gemm.Gemm.,, 1992,1992, 23,23, 2

TableTable 1.1. ChemicalChemical compositioncomposition ofof meteoriticmeteoritic olivinesolivines fromfrom Esquel,Esquel, ArgentinaArgentina

1 2 3

wt.wt.%%

Si0SiO2 40.6940.69 40.7540.75 41.0941.09 MgOMgO 43.1343.13 43.2843.28 43.4943.49 FeOFeO 14.2114.21 14.0214.02 13.5713.57 MnOMnO 0.340.34 0.380.38 0.320.32

numbenumberr ooff cationscations oonn ththee basbasee 0=0=44

SiSi 1.031.03 1.031.03 1.041.04 MgMg 1.631.63 1.631.63 1.631.63 FFee 0.300.30 0.300.30 0.20.299 MMnn 0.00.011 0.010.01 0.00.011

percentagepercentage distributiondistribution

forsteriteforsterite 84.0284.02 84.0284.02 84.4684.46 fayalitfayalitee 15.415.466 15.4615.46 15.0315.03 tephroitetephroite 0.50.522 0.520.52 0.510.51

S.5. MicroscopicaMicroscopicall featuresfeatures AAtt ththee crossingcrossing pointpointss blackblack opaqueopaque shapelessshapeless inclusioninclusionss (probably(probably residueresiduess ofof thethe nickeliferousnickeliferous StudiesStudies witwithh anan immersionimmersion microscopemicroscope yieldedyielded ironiron ofof thethe meteoriticmeteoritic matrix)matrix) areare embedded.embedded. ververyy interestininterestingg internalinternal features.features. AlAlll samplessamples investigateinvestigatedd showshow needle-likeneedle-like inclusionsinclusions (probably(probably 6.6. ConclusionsConclusions holloholloww tubestubes)) runninrunningg througthroughh ththee wholewhole stonestone andand crossingcrossing atat angleangless ofof 90°90° duedue toto ththee ThThee cutcut meteoritimeteoriticc olivinesolivines ofof ththee pallapallasit sitee orthorhombicorthorhombic crystalcrystal systemsystem ofof olivinolivinee (Figure(Figure 3)3).. stony-ironstony-iron fromfrom EsqueEsquell iinn Patagonia,Patagonia, Argentina,Argentina, possesspossess physicaphysicall andand chemicalchemical propertiesproperties typicatypicall ooff

FigFig.. 33.. Needle-likNeedle-likee inclusionsinclusions (probably(probably holloholloww tubes)tubes) crossingcrossing aatt anglesangles sublunarysublunary olivinesolivines.. ThThee microscopicamicroscopicall features,features, ooff 90°90°.. AtAt thethe crossincrossingg pointpointss opaquopaquee shapelesshapelesss inclusionsinclusions however,however, araree unusuaunusuall andand notnot typicatypicall forfor sublusublu (probably(probably residueresiduess ooff thethe nickliferousnickliferous iroironn ofof thethe meteoriticmeteoritic narynary gemgem olivines.olivines. matrix)matrix) araree embeddedembedded.. ImmersionImmersion.. x25x25.. ReferenceReferencess BankBank,, H.H.,, 1984.1984. FasFastt farbloserfarbloser OliviOlivinn ausaus SriSri LankaLanka.. Z. Dt. Gemmaz.Gemmol. -4. Ges., 33, 139-40.139-40. ^-^:^m:^T^' Bank,Bank, H.,H., 1986.1986. HochlichtbrechendeHochlichtbrechende OlivinOlivinee auauss defder EifelEifel.. Z. Dt. Gemmol. Ges"Ges., 35,35, 185-6.185-6. Deer, W.A.,W.A., Howie, Howie, R.A., R.A., Zussman, Zussman, J., 1983. J. , 1983. An Introduction An Introduction to the to Rock-Forming the Rock Forming Minerals. 14th14th edn.edn. Longman.Longman. Runciman, W.A., W.A., Sengupta, Sengupta, D., Courley, D., Courley, J.T., 1973. J.T., The 1973. polarized The polarized spectraspectra ofof iroironn iinn silicates.silicates. IIII OlivineOlivine.. American Mineralogist, 5858,, 451-6.451-6. Smith,Smith, H.G.H.G.,, LangerLanger,, K.,K., 1982.1982. SingleSingle crystacrystall spectrspectraa ooff olivineoliviness inin ththee rangrangee 40,000-5,0040,000-5,0000 cmcm 1 aatt pressurespressures uupp ttoo 202000 kbarkbar.. Amen'canAmerican m^, ' îf-Ai*^^-*! Mineralogist, 67,343-8.67, 343-8. Webster,Webster, R.R. (revise(revisedd byby Anderson,Anderson, B.W.),B.W.), 1983.1983. Gems, Their Sources, DescriptionsDescnptions andand Identification.Identification. 4th4th edn.edn . Butterwonhs,Butterworths, London.London . [Manuscript[Manuscript receivedreceived 11 November 1991)1991] J. Gemm., 1992, 23, 2 89

The Museum of Ouro Preto, Minas Gérais, Brazil Dr Francisco Müller Bastos, FGA, GG

Belo Horizonte, Minas Gerais, Brazil

In early times, the establishment of many small city of Belo Horizonte was inaugurated and the villages in the State of Minas Gérais and also in capital of the State of Minas Gérais was transferred other parts of Brazil, was a consequence of the from Ouro Preto to this new location. search for gold, diamonds and precious stones. The Ouro Preto, one of the oldest cities in Brazil, city of Ouro Preto followed this rule. By the year located at an altitude of 1150 metres, can be reached 1696, a man known as Duarte Nunes, also known as by two fairly good paved roads 97 kilometres distant 'The Mulato', first discovered gold in Ouro Preto - from Belo Horizonte; approximately 33 kilometres small nuggets with a steel colour. Thus, the first by the BR-040 and 64 kilometres along another name given to this place was Vila Rica do Ouro state road. Companies which work iron ore are Preto (Rich Village of Black Gold). Later this name located along the road. The famous Pico de Itabira was changed to Vila Rica, and finally to Ouro Preto. (69% pure hematite) which as a landmark for the Until 1729, only gold was found by the 'mineiros' in 'bandeirantes', scouts in search of gold, who de the soil of Minas Gérais, but later diamonds of the parted from the coast in Rio de Janeiro and headed Tejuco, in the village of Serro do Frio (later known into the interior, can be seen on the right. Ten as Diamantina) were also discovered. kilometres from Ouro Preto, a large aluminium Historic episodes of the 'Inconfidencia Mineira', factory in the Saramenha district, exploits the large a movement which resulted in national independ resources of bauxite which exist in the region. ence, occurred during the gold cycle. From the Finally, we arrive in Ouro Preto, where the Itacolo- years 1721 to 1897, Ouro Preto was the capital of mi Peak (the stone and the daughter in Indian Minas Gérais State. On 12 December 1897, the new language), 1752 metres high, can be seen as a

Fig. 1. The exterior of the Museum at Ouro Preto.

(Photo: the author)

background to the city. Ouro Preto was nominated by the United Na tions as a World Historical Monument. The city and the small villages which surround it are also known as the best topaz producers in the world, including yellow, red, orange and pink colours. Claude Henry Gorceix, born in France in Saint Denis des Murs (Haute Vienne) on 19 October 1842, arrived in Brazil on 17 October 1876 and at the age of 34 years founded the Ouro Preto School of Mines in a building which was formerly the Palace of the Government of the State of Minas Gerais. Gorceix brought with him several samples of minerals, and continued to collect samples in the Ouro Preto region, creating a collection which is presently one of the most important in the world. From 1881 to 1885, Gorceix also wrote many articles about Brazilian minerals. These articles and archives are preserved in the Ouro Preto School of Mines Museum. The museum is an old, two storey building located on Praça Tiradentes N° 20 (Tiradentes Fig. 2. A very large quartz crystal weighing some 6000kg and Square) in the centre of town (Figure 1). The measuring Im x lm, in the entrance hall of the Museum. museum was restored in 1974 and exhibits are open (Photo: R.Mendes) to the public from 12 noon to 5.00pm. A 50 cents huge quartz crystal weighing 6000 kilograms, (American) admission fee is charged and the money which measures one metre high by one metre wide is used to buy new specimens and for the conserva (Figure 2). It should be noted that the floors of the tion of the museum. In the entrance hall we see a great hall on the ground level are made of a perfectly

Fig. 3. A view of the exhibition in the great hall of the Museum; note the floor of beautifully polished quartzite. (Photo: R. Mendes) J. Gemm., 1992, 23, 2 91

euclase crystals - blue, light blue and pale yellow in colour; a beautiful round morganite 10cm in dia meter; a transparent yellowish-green baryte; a group of magnesite crystals, each crystal measuring approximately 7cm and a tabular pyrrhotite crystal about 12cm long. Many varieties of beryl can be seen, including goshenite, morganite, heliodor, aquamarine and emerald. The tourmaline group is represented by the species elbaite, dravite, uvite, liddicoatite, schorl, buergerite and ferri dravite. Special exhibitions include a collection of iron minerals, which are abundant in this region includ ing hematite, martite, magnetite, limonite, pyrolu- site and also a glass case with calcium carbonate minerals enrich the museum, as well as tektites, platinum, gold, silver and the reproduction of the largest diamonds in the world which ensures that all the minerals found in Brazil are displayed in the museum collections. On the second floor of the museum, besides the five rooms with the minerals, there is a chapel with old images of saints and another room with paleon- tological specimens, fossils, shells and skeletons of birds and wild animals. Finally, a room is dedicated to Gorceix, the Fig. 4. A fine terminated crystal of orange topaz 13cm in founder, showing some old instruments used to test height in the Museum. (Photo: R. Mendes) stones and also some early mineralogical literature

polished, beautiful white and grey quartzite (Figure Fig. 5. A spectacular specimen of hematite measuring 21 x 17cm in the Museum. (Photo: R. Mendes) 3). About 98% of the specimens displayed in the museum are from Brazil. However, a lovely vivianite from France is shown in one of the glass cases on the first floor. There are two distinct mineral collections. The first, more technical and started by Gorceix, which presently comprises over 24,000 items, occupies a large room on the first floor of the museum. The best minerals belong to this first collection, which is displayed in ten glass island cases and in seven wall cases around the room. Four spots of special lighting are placed over each glass case, giving perfect illumination. The second collection, not as rich as the first, has approximately 2000 minerals occupying five rooms on the second floor of the museum. These minerals are distributed in some forty glass cases in various rooms. All minerals are classified according to name, place of origin and chemical formulae. Some outstanding specimens of the collection include a perfectly terminated yellowish-red topaz measuring 13cm in height (Figure 4), considered one of the best specimens of the museum; a spectacular spéculante 21 x 17cm (Figure 5) considered one of the world's best; a dark green flawless crystal of the rare mineral euclase, shown together with other 92 J. Gemm., 1992, 23, 2

Fig. 6. The author (right) and Mr Cesar Mendonça in front of a bust of Claude Henry Gorceix, the founder of the Museum. (Photo: the author)

and historical documents. Eugene Hussack, the and display of the minerals in the museum. famous German mineralogist, discovered a mineral which he named gorceixite in his honour. Hussack Acknowledgements also wrote many papers which are housed in the The author expresses his thanks to Mr Jorge museum archives. Geraldo Brito dos Santos who made the arrange In addition to the Mineralogy Museum, Ouro ments xto visit the museum, and to Mr Cesar Preto has the most important School of Engineering Mendonça for all his advice and co-operation in Brazil. A committee composed of Mr Geraldo during this visit. Cardoso, Mr Osmar Alves de Oliveira Jr, and Mr Cesar Mendonça, is responsible for the acquisition [Manuscript received 5 July 1991.] JJ.. Gemm.Gemm.,, 19921992,, 2323,, 2 9933

LamellaLamellarr inclusioninclusionss iinn spinelspinelss frofromm MorogorMorogoroo areaarea,, TanzaniTanzaniaa Dr Karl SchmetzerSchmelzer! 1 andand DrDr AxelAxel Berger Berger 2 2

1IMarbacherMarbadier Str.Str. 22b,22b, D-8067D-8067 Petershausen,Petershausen, GermanyGermany 22InstitutInstitut füfurr MineralogiMineralogiee dederr TechnischeTechnischenn HochschuleHochschule,, SchnittspahnstrSchnittspahnstr.. 99,, D-610D-61000 DarmstadtDarmstadt,, GermanGermanyy

AbstracAbstractt LamellaLamellarr doubldoublee refractivrefractivee inclusioninclusionss iinn spinelspinelss fromfrom ttoo 0.10.155 wt.wt.%% V anandd uupp ttoo 0.0.22 wt.wt.%% TTii werweree Morogoro area, Tanzania,Tanzania, were were identified identified by by transmis transmission sion electroelectronn microscopimicroscopicc techniquetechniquess aass iron-freeiron-free,, highighh determinedeterminedd bbyy electroelectronn microprobmicroprobee (cobal(cobaltt concon titanium-bearintitanium-bearingg högbomitehiigbomite.. ThThee inclusioninclusionss occuoccurr aass tenttentss werweree belobeloww ththee detectiodetectionn limilimitt ooff ththee micropmicrop foufourr setsetss ooff thithinn lamellalamellaee paralleparallell ttoo ththee octahedraoctahedrall facefacess robrobee bubutt werweree proveprovenn bbyy X-raX-rayy fluorescencfluorescencee analyanaly of the spinelspinel hosthost crystals. crystals. ses)ses),, anandd ththee absorptioabsorptionn bandbandss iinn ththee spectrspectraa ooff spinespinell crystalcrystalss witwithh differendifferentt coloratiocolorationn werweree conseconse IInn JunJunee 1987,1987, ononee oofthef the presenpresentt authorauthorss receivedreceived quentlquentlyy assigneassignedd ttoo chromiumchromium,, vanadiumvanadium,, iroironn (i(inn ththee firsfirstt samplesampless ooff aann apparentlapparentlyy neneww sourcsourcee ooff differendifferentt valencvalencee statesstates)) anandd cobalcobaltt (Schmetze(Schmetzerr et naturanaturall gegemm qualitqualityy spinelsspinels.. ThThee redred,, pinkpink,, orangeorange,, al., 1989)1989).. IInn contrascontrastt ttoo thesthesee non-spectacularnon-spectacular reddish-purplereddish-purple,, purplish-blupurplish-bluee anandd blubluee crystalscrystals resultsresults,, microscopimicroscopicc investigationinvestigationss indicateindicatedd thatthat forminformingg octahedroctahedraa uupp ttoo abouaboutt 1clcmm iinn sizsizee supsup abouaboutt 7070%% ooff ththee spinespinell samplesampless frofromm ththee neneww posedlposedlyy originateoriginatedd frofromm ththee MorogorMorogoroo areaarea,, whichwhich sourcsourcee iinn TanzaniTanzaniaa showeshowedd lamellalamellarr inclusioninclusionss aass a iiss situatesituatedd abouaboutt intermediatintermediatee betweebetweenn DodomaDodoma characteristicharacteristicc featurefeature,, whicwhichh wawass neitheneitherr observedobserved anandd DaDarr eess SalaaSalaamm iinn centracentrall TanzaniTanzaniaa (se(seee alsalsoo bbyy ththee authorauthorss iinn gegemm qualitqualityy spinelspinelss beforbeforee nonorr wawass HännHiinnii anandd SchmetzerSchmetzer,, 1991)1991).. MeanwhileMeanwhile,, ththee auau describedescribedd anandd identifieidentifiedd iinn specifispecificc mineralogicamineralogicall oorr thorthorss obtaineobtainedd severaseverall parcelparcelss ooff facetefacetedd anandd roughrough gemmologicagemmologicall paperspapers.. ThThee firsfirstt hinhintt towardtowardss thesethese gegemm qualitqualityy spinelspinelss frofromm ththee neneww TanzaniaTanzaniann source,source, characteristicharacteristicc lamellalamellaee iiss founfoundd iinn ththee publicatiopublicationn ooff whicwhichh werewere submittedsubmitted bbyy differentdifferent personpersonss inin thethe BanBankk et al. (1989),(1989), whowho mentionedmentioned 'irregular'irregular growthgrowth tradetrade toto ththee authorsauthors oror ttoo colleagues.colleagues. AlAlll thosethose structures'structures' iinn theitheirr TanzaniaTanzaniann spinels.spinels. InIn addition,addition, dealers,dealers, witwithh oneone single exception,exception, independentlyindependently KanKanee (1990)(1990) mentionementionedd 'numerous'numerous sheetssheets ooff namenamedd ththee MorogoroMorogoro areaarea inin TanzaniaTanzania asas thethe originorigin polpolysyntheticy synthetic twinnintwinningg planesplanes'' iinn spinespinell frofromm TanTan ofof ththee gemstonesgemstones.. AccordinAccordingg toto ththee factfact thathatt mosmostt ooff zama.zania. ththee samplessamples fromfrom allall differentdifferent parcelsparcels,, whichwhich werewere TheThe lamellarlamellar structuresstructures ttoo bebe describeddescribed werewere examinedexamined byby thethe presentpresent authorsauthors containedcontained doublydoubly observeobservedd iinn foufourr differendifferentt orientationorientationss paralleparallell toto refractive,refractive, lamellarlamellar inclusionsinclusions ttoo bbee describeddescribed later,later, ththee octahedraoctahedrall {Ill}{111} facesfaces ofof thethe spinelspinel hosthost itit isis almosalmostt certaincertain thathatt allall thesthesee parcelsparcels ofof gemgem crystals.crystals. InIn eacheach viewview parallelparallel ttoo oneone ooff ththee <<110 11 0>> spinelsspinels camecame fromfrom oneone singlesingle localitylocality only.only. ConseConse axesaxes ooff ththee spinelspinel hosthostss (Figure(Figure 1),1), twtwoo setssets ofof thinthin quently,quently, ththee UmbaUmba valley,valley, inin northernorthernn Tanzania,Tanzania, lamellalamellaee werewere observedobserved paralleparallell ttoo ththee octahedraloctahedral closeclose toto ththee KenyaKenyann borderborder,, whichwhich iiss quotedquoted bbyy spinelspinel faces,faces, formingforming characteristiccharacteristic anglesangles ooff BankBank et al. (1989)(1989) asas sourcesource ofof thethe newnew EastEast AfricanAfrican 109.47°109.47° andand 70.53°,70.53°, respectively.respectively. UnderUnder crossedcrossed gemgem spinels,spinels, mostmost probablyprobably isis invalidinvalid asas a localitylocality polarizerspolarizers inin thethe gemmologicalgemmological microscopemicroscope usingusing forfor thesethese newnew gemgem materials.materials. methylenemethylene iodideiodide asas immersionimmersion liquidliquid (Figure(Figure 2),2), PhysicalPhysical andand chemicalchemical propertiesproperties ofof thethe spinelsspinels thethe inclusionsinclusions werewere foundfound toto consistconsist ofof doublydoubly werewere foundfound toto bebe inin thethe rangerange ofof naturalnatural gemgem qualityquality refractiverefractive lamellae.lamellae. BecauseBecause ofof thethe smallsmall thicknessthickness spinels,spinels, e.g.e.g. fromfrom SriSri LankaLanka andand Burma.Burma. TraceTrace ofof thethe lamellae,lamellae, characterizationcharacterization andand identificationidentification elementelement analysesanalyses asas wellwell asas spectroscopicspectroscopic investigainvestiga ofof thethe mineralmineral inclusionsinclusions byby electronelectron microprobemicroprobe tionstions (d.(cf. SchmetzerSchmetzer et al., 1989)1989) revealedrevealed results,results, waswas notnot successful.successful. whichwhich indicatedindicated nono differencesdifferences worthworth mentioningmentioning However,However, byby thethe applicationapplication ofof transmissiontransmission betweenbetween samplessamples ofof thisthis newnew sourcesource andand gemgem spinelsspinels electronelectron microscopicmicroscopic techniquestechniques usingusing ion-beamion-beam fromfrom thethe longlong knownknown localitieslocalities inin SriSri LankaLanka andand thinnedthinned petrographicpétrographie thinthin sections,sections, thethe presentpresent Burma.Burma. DependentDependent onon thethe colourcolour ofof thethe individualindividual authorsauthors werewere ableable toto characterizecharacterize andand identifyidentify thethe samples,samples, tracetrace elementelement contentscontents inin thethe rangerange ofof 0.050.05 inclusionsinclusions (Schmetzer(Schmetzer andand BergerBerger 1990).1990). TheThe exactexact wt. % toto 0.550.55 wt.wt. % Cr,Cr, 0.250.25 wt.wt. %% toto 1.251.25 wt.wt. %% Fe,Fe , upup thicknessthickness ofof differentdifferent lamellaelamellae waswas determineddetermined toto bebe

FigFig.. 1.1. PlanePlane polarizepolarizedd light,light, 40x.40x. FigFig.. 22.. CrossedCrossed polarizers,polarizers, 40x.40x.

FigsFigs.. 1I,, 2.Doubl2.Doublee refractivrefractivee lamellaelamellae ooff hOghögbomit bornitee inin pinpinkk spinespinell (Fig(Fig.. 1I)) frofromm TanzaniaTanzania.. TheThe lamellaelamellae areare orientatedorientated parallelparallel toto twotwo octahedraoctahedrall {III}{111} facesfaces ofof thethe hosthost.. ViewView parallelparallel ttoano an < 110>110> axisaxis ofof ththee spinelspinel crystalcrystal,, usingusing aann immersionimmersion microscopmicroscopee withwith methylenmethylenee iodidiodidee aass immersioimmersionn liquid.liquid. variablevariable betweebetweenn 0.010.01 /m/-LIDi anandd 0.10.1 /mm./-LID. UsingUsing AcknowledgementsAcknowledgements electronelectron diffraction,diffraction, ththee lamellaelamellae werewere foundfound toto havehave ThThee authorsauthors areare gratefugratefull ttoo DDrr H.A.H.A. HännHannii ooff trigonatrigonall (rhombohedral)(rhombohedral) symmetrysymmetry withwith uniunitt cellcell Basel, Switzerland,Switzerland, anandd ttoo thethe companiescompanies ooff GebGeb dimensionsdimensions ooff aoa0 = 5.75.7 AÀ anandd cCo0 ""~ 1212 x 44.. 6565 AÂ = rüderuderr LeyserLeyser,, JuliuJuliuss PetschPetsch JJrr anandd KarlKarl EgonEgon Wild,Wild, 55.855.8 ÂA.. QuantitativQuantitativee EDX-analyseEDX-analysess witwithh a 15nm15nm allall oofIdarf Idar ObersteinOberstein,, GermanyGermany,, whwhoo kindlykindly submitsubmit diameterdiameter electronelectron spotspot characterizedcharacterized thethe lamellaelamellae aass tedted thethe majomajorr parcelparcelss ooff spinelsspinels frofromm TanzaniTanzaniaa forfor Mg-Al-TMg-AI-Tii oxidesoxides.. IInn summary,summary, ththee lamellaelamellae werewere ththee presenpresentt investigation.investigation. identifiedidentified aass anan iron-free,iron-free, highhigh titanium-bearingtitanium-bearing membermember ooff thethe chemicallchemicallyy varyinvaryingg hogbomitehögbomite ReferencesReferences senes.series. Bank,Bank, H.,H., Henn,Henn, U.,U., Petsch,Petsch, E.,E., 1989.1989. SpinelleSpinelle auauss demdem HögbomitHogbomitese s araree hexagonahexagonall oorr trigonatrigonall (rhom(rhom Umba-TalUmba-Tal,, TanzaniaTanzania.. Z.Z. Dt. Gemmol. Ges., 3838,166-8., 166-8. bohedral) Fe-Mg-Al-Ti oxides with complex che Coolen,Coolen, J.J.M.M.M.J.J.M.M.M.,, 1981.1981. HiigbomiteHögbomite andand aluminiualuminiumm spinelspinel bohedral) Fe-Mg-Al-Ti oxides with complex che frofromm somesome metamorphicmetamorphic rockrockss andand Fe-TFe-Tii ores.ores. micalmical compositiocompositionn (Petersen(Petersen et al. 1989).1989). StructurStructur N.Jb.Miner.Mh., 1981,374-84.1981, 374-84. ally,ally, hogbomitehögbomite iiss closelyclosely relatedrelated ttoo spinelspinel iinn thathatt thethe Gatehouse,Gatehouse, B.M.B.M.,, GreyGrey,, I.E.I.E.,, 1982.1982. ThThee crystacrystall structurstructuree ooff hogbomitehögbomite structurestructure isis derivederivedd frofromm a spinelspinel strucstruc högbomite-8Hhiigbomite-8H.. Amer. Mineral., 6767,, 373-80.373-80. ture through partial replacement of magnesium HänniHanni,, H.A.H.A.,, Schmetzer,Schmetzer, K.K.,, 1991.1991. NeNeww rubierubiess fromfrom thethe ture through partial replacement of magnesium MorogoroMorogoro AreaArea,, Tanzania.Tanzania. Gems&Gems & Gemology, 27,156-67.27, 156-67. atomsatoms byby titaniumtitanium (Gatehouse(Gatehouse & GreyGrey,, 1982)1982) KaneKane,, R.E.,R.E., 1990.1990. SpinelSpinel frofromm Tanzania.Tanzania. Gems& Gemology, 2626,, 4 accordingaccording toto thethe formulaformula 2 Mgz+Mg2+ --->—> TiTi4++ (Coolen,(Coolen , 156-7.156-7. 1981).1981). SimilarSimilar structuresstructures araree alsoalso knowknownn forfor thethe NuberNuber,, B.,B., Schmetzer,Schmetzer, K.K.,, 1983.1983. CrystaCrystall structurestructure ooff ternaryternary Be-Mg-AIBe-Mg-Al oxides:oxides: taaffeitetaaffeite,, BeMg AI,O'6'Al O , anandd musgravite,musgravite, Be-Mg-ABe-Mg-AIl oxideoxidess taaffeittaaffeitee anandd musgravitemusgravite (Nuber(Nuber 3 8 16 BeMgBeMg,AI2Al60O1212.. N.Jb.Miner.Mh., 1983,393-402.1983, 393-402. & Schmetzer,Schmetzer, 1983).1983). Petersen,Petersen, E.E.U. U.,, EsseneEssene,, E.J.,E.J., PeacorPeacor,, D.R.D.R.,, Marcotty,Marcotty, L.A.,L.A., IInn practicalpractical gemmologygemmology,, thethe observationobservation ofof diffediffe 1989. The occurrenceoccurrence of ofhiigbomite högbomite in in high-grade high-grade metamorphic metamor renrentt setssets ofof doubldoublyy refractivrefractivee lamellalamellarr inclusioninclusionss iinn a rocks.phic rocks. Contr. Contr. Mineral. Mineral. Petrol., Petrol., 101, 350-60. 101, 350-60. spinel of unknown origin is able to characterize the Schmetzer, K., K., Berger, Berger, A., A., 1990. 1990. Lamellar Lamellar iron-free iron-free högbomite-24R hiigbomite- spinel of unknown origin is able to characterize the from24R Tanzania. from Tanzania. N.Jb.Miner., N.Jb.Miner., 1990, 401-12. 1990,401-12. samplesample aass naturalnatural spinelspinel originatinoriginatingg fromfrom Tanzania.Tanzania. Schmetzer,Schmetzer, K.,K., Haxel,Haxel, c.,C., AmthauerAmthauer,, G.,G., 1989.1989. ColouColourr ooff naturalnatural AccordinAccordingg ttoo ththee facfactt thathatt flux-grownflux-grown syntheticsynthetic spinels,spinels, gahnospinelsgahnospinels anandd gahnitesgahnites.. N.Jb.Miner.Abh., 160160,, spinelsspinels araree nownow appearinappearingg iinn increasinincreasingg quantitiesquantities 159-80.159-80. iinn thethe trade,trade, ththee diagnosticdiagnostic featurefeature describeddescribed inin thisthis papepaperr mamayy bbee helpfuhelpfull occasionally.occasionally. [[ManuscriptManuscript receivedreceived 23 23 MayMay 1991.1991 .J] J.J. Gemm.Gemm.,, 1992,1992, 23,23, 2 9595

DeterminatioDeterminationn ofof dispersiodispersionn usingusing a refractometerrefractometer W. Wm. Wm. Hanneman, Hanneman, Ph.D. Ph.D.

PPOO BoBoxx 24532453,, CastrCastroo Valley,Valley, CACA 94546,94546, USAUSA

WheWhenn usingusing whitwhitee lighlightt witwithh a refractometerrefractometer,, thethe index)index).. AnAnyy 'index'index ofof refractionrefraction'' valuesvalues obtainedobtained rainborainboww effecteffect onon thethe shadowshadow edgeedge resultingresulting fromfrom fromfrom ththee refractometerefractometerr scalescale whenwhen usingusing otherother dispersiondispersion isis readilreadilyy apparent.apparent. SinceSince thethe refractorefracto wavelengthwavelengthss ofof lighlightt havehave nnoo realreal meaning.meaning. metemeterr isis alreadyalready usedused toto determinedetermine refractiverefractive index,index, NeverthelessNevertheless,, ththee numericanumericall scalescale onon a refractorefracto birefringencebirefringence andand opticoptic character,character, itit seemsseems reasonreason metemeterr cancan bbee useusedd forfor indicatingindicating ththee effectseffects ooff ableable ttoo expectexpect thathatt iitt alsoalso couldcould bbee useusedd ttoo determinedetermine dispersiodispersionn occurringoccurring aatt ththee gem-refractometergem-refractometer dispersion.dispersion. IndeedIndeed,, iitt can.can. prisprismm interface.interface. TheThe dispersiondispersion valuevalue iiss anan intrinsicintrinsic DispersionDispersion,, bbyy definition,definition, iiss ththee numericanumericall valuevalue physicaphysicall propertpropertyy ofof a gemgem,, howeverhowever,, thethe opticaloptical equalequal ttoo nGnG minuminuss nnB'B. IItt wouldwould appearappear thatthat oneone propertiepropertiess ofof refractometerefractometerr prismsprisms areare definedefinedd bbyy couldcould ususee redred andand blubluee filters ttoo definedefine thethe lightlight theitheirr manufacturersmanufacturers.. Consequently,Consequently, a separateseparate sources,sources, determinedetermine thethe indicesindices ofof refractionrefraction onon thethe calibrationcalibration scalescale iiss requirerequiredd forfor eacheach makmakee ooff refractometerrefractometer scale,scale, andand calculatecalculate ththee valuevalue forfor refractometer.refractometer. TheThe actualactual calibrationcalibration scalescale iiss alsalsoo a dispersiondispersion.. functiofunctionn ooff thethe reredd andand blueblue lighlightt sourcessources used.used. OverOver thethe yearsyears,, a numbenumberr ofof investigatorsinvestigators havehave A usefuluseful calibrationcalibration scalescale cancan bebe constructedconstructed trietriedd thithiss approach.approach. HoweverHowever,, onlyonly AmericanAmericanss seemseem frofromm ththee resultresultss obtainedobtained fromfrom twtwoo referencreferencee gemgemss - toto getget reasonablereasonable results.results. ThereThere iiss anan explanationexplanation forfor benitoitebenitoite,, havinhavingg a dispersiodispersionn valuvaluee ooff 0.0470.047,, andand this.this. BesideBesidess demonstratindemonstratingg whwhyy suchsuch resultresultss werewere fluoritefluorite,, havinhavingg a dispersiondispersion valuvaluee ofof 0.007.0.007. RedRed andand simplysimply fortuitous,fortuitous, thithiss papepaperr wilwilll presenpresentt a methodmethod blubluee lighlightt iiss producedproduced bbyy thethe ususee ofof filters anandd thethe whichwhich cancan bbee useusedd bbyy anyoneanyone toto actuallyactually determinedetermine numericalnumerical differencedifference ooff thethe refractometerrefractometer scalescale dispersiondispersion usinusingg a refractometer.refractometer. readingreadingss (6(A scale)scale) iiss plotteplottedd againstagainst thethe knownknown FoForr allall gemstonesgemstones,, ththee indeindexx ofof refractiorefractionn forfor blueblue dispersiondispersion valuesvalues.. A lineline isis constructedconstructed connectingconnecting lighlightt (nG)(nG) iiss greategreaterr thanthan thathatt forfor reredd lightlight (n(nB)'B). thesethese twtwoo pointpointss ttoo serveserve asas thethe calibration.calibration. FigurFiguree 1 HoweverHowever,, whenwhen thesthesee 'apparent'apparent valuesvalues'' araree deterdeter showsshows thethe calibrationcalibration scalesscales forfor twotwo widelywidely usedused minedmined oonn ththee refractometerefractometerr scalescale,, 'nB''nB' hashas a greatergreater commerciacommerciall refractometerrefractometerss - ththee BritisBritishh DialdexDialdex valuvaluee thathann doesdoes 'no'nG:' ThiThiss iiss why,why, whewhenn usinusingg a redred andand ththee AmericaAmericann DupleDuplexx II.II. filter toto producproducee monochromaticmonochromatic light,light, oneone mustmust TheThe pointpointss forfor garnetgarnet,, rubyruby andand tourmaline,tourmaline, werewere subtractsubtract ththee valuvaluee ofof 0.003-0.0050.003-0.005 fromfrom thethe refractorefracto positionepositionedd onon thethe basisbasis ofof publishepublishedd dispersiondispersion metemeterr scalescale readingreading inin orderorder ttoo obtainobtain thethe correctcorrect RIRI valuevaluess andand experimentallyexperimentally measuredmeasured 6A scalescale value.value. valuesvalues.. TheyThey confirmconfirm ththee generalgeneral validityvalidity ofof thisthis ThThee reasonreason forfor thisthis iiss thatthat dispersiodispersionn andand RIRI areare calibrationcalibration scheme.scheme. measuremeasuress ofof whawhatt happenshappens toto lighlightt aatt ththee interfacinterfacee ooff a gemgem andand air.air. TheThe refractometerrefractometer reading,reading, onon thethe Fortuitous ResultsResults otherother handhand,, iiss a functionfunction ofof whatwhat happenhappenss toto lighlightt atat TheThe reasonreason forfor AmericanAmericanss gettingettingg 'reasonable''reasonable' ththee interfacinterfacee betweenbetween ththee gemgem anandd thethe refractometerrefractometer resultresultss eveneven thougthoughh usinusingg thethe invaliinvalidd assumptionassumption prism.prism. thathatt ththee 6A scalescale readinreadingg = dispersion,dispersion, isis alsoalso SinceSince airair hashas anan indexindex ofof refractiorefractionn lowerlower thanthan thatthat illustrateillustratedd inin FigurFiguree 1.1. ThisThis erroneouserroneous relationshiprelationship ofof ththee gemgem andand thethe prisprismm hahass ononee highehigherr thathann thethe isis representerepresentedd bbyy thethe dotteddotted linlinee extendingextending upwardsupwards gemgem,, ththee rainborainboww iinn ththee refractometerrefractometer appearsappears toto ttoo ththee right.right. NotNotee ththee slopeslope iiss oppositeopposite ttoo thosthosee ooff spreadspread iinn thethe 'wrong'wrong'' direction.direction. ththee calibrationcalibration lineslines.. Consequently,Consequently, inin ordeorderr ttoo bebe useful,useful, refractorefracto ThThee dotteddotted lineline intersectsintersects ththee AmericaAmericann DuplexDuplex metemeterr scalesscales araree alalll calibratecalibratedd iinn termtermss ofof a singlesingle IIII calibrationcalibration linlinee atat a dispersiodispersionn valuevalue ooff 0.020.0.020. wavelengtwavelengthh - 589nm.,589nm., i.e.i.e. nnDo oror yelloyelloww lightlight.. ThisThis SinceSince a greagreatt numbernumber ooff thethe lowelowerr RRII colouredcoloured valuvaluee hahass beebeenn designateddesignated asas thethe RIRI (refractive(refractive gemstonegemstoness havehave dispersiodispersionn valuesvalues ofoftha thatt magnitudemagnitude

(e.g. ruby, garnet and tourmaline), 'reasonable 2. Determination of lower standard point. values' can be obtained by using either line as the A. Repeat steps 1A, B, and C using the fluorite calibration line. standard. On the other hand, English investigators using the Dialdex refractometer would find that the true 3. Construction of Calibration Chart. calibration curve is crossed by the dotted line at a A. Construct a graph relating A Scale Reading vs. value of only 0.010. For most gemstones, this is not Dispersion and plot the points for the standards a 'reasonable value' of dispersion and the investiga as shown in Figure 1. tor is immediately alerted to the error. B. Construct a straight line connecting the refer ence points. Determination of dispersion using a gemmological refractometer 4. Determination of Dispersion of Unknowns. A. Repeat the steps outlined in 1A, B, and C using Equipment: the unknown specimen. Gemmological refractometer of any manufacture. B. Using the value of A Scale Reading and the Red and blue filters to define light sources. Disper calibration chart, determine the dispersion of sion reference standards: fluorite (0.007) and the unknown. benitoite (0.047). Graph paper. [Manuscript received 24 September 1990.]

Procedure:

1. Determination of upper standard point. A. Using the blue filter, determine the refracto meter scale reading corresponding to the shadow edge for benitoite. B. Repeat step A using the red filter. C. Determine the absolute difference of the two readings. This is designated the A Scale Reading. JJ.. Gemm.,Gemm., 1992,1992, 2323,, 3 96a96a

DeterminationDetermination ofof dispersiondispersion usinusingg a refractometerrefractometer WW.. Wm.Wm. Hanneman,Hanneman, Ph.Ph. D.D.

DETERMINATIONDETERMINATION OFOF DISPERSIONDISPERSION USINUSINGG A GEMOLOGICAGEMOLOGICALL REFRACTOMETERREFRACTOMETER

0.0280.028 -, , 1 , 1 , , r

0.026 "-

0.024 , 0.022 " ~ 0.020 • ~ v , .. .1::~ v I' S 0.018 --0 ~ ~ .....s:: " IJ(;; U Cii >. Z -~ gj 0.016 8.0 "-~ct.t.t ~ 1'1-< ~ ~ ::: 0.014 ' g -t; K 0 , t-t- l'J , S I ro i?i 0.012 ---...... , c.? ~ 0.010 ~ "'- ,,# - " ~ U ~ r/l 0.008 , , - ~ v , ...... ~ 0.006 - ...... ·0- - .....~ s:: 0.004 ~~IJlJ v- P=l ~ ~ 0.002 o " "- 0.0050.005 0.010.0155 0.020.0255 0.030.0355 0.0450.045 - DISPERSIODISPERSIONN FigFig.. 1.1. ThThee calibratiocalibrationn scalescaless forfor twtwoo widelywidely useusedd commercialcommercial refractometersrefractometers - thethe BritishBritish DialdeDialdexx anandd ththee AmericanAmerican DupleDuplexx II.II. J. Gemm., 1992, 23, 2 97

Magnetic resonance distinction between synthetic and natural 'padparadscha' sapphires G.J. Troup, D.Sc., 1 D.R. Hutton, Ph.D., 1 and Belinda Turner

1Physics Department, Monash University, Clayon 3168, Victoria, Australia 2Tyler, Texas, USA

Abstract obtain the synthetic material than the natural! In The examination of natural and synthetic sapphires, the Chatham case, this is presumably because in the 'padparadscha' ('lotus flower') colour range, by Chatham ceased production of their 'padparadscha' magnetic resonance spectroscopy, gave the following sapphire in 1990, after commencing about 10 years results. Ferric iron is readily detectable in Sri Lankan before, with no plans to continue. and Tanzanian natural material, but is absent, or very difficult to detect, in synthetic boule (flame fusion) material. The lines are much broader in the Tanzanian Materials and Methods stones than the Sri Lankan. Ferric iron is also easily A variety of natural 'padparadscha' and similarly detectable in flux-grown (Chatham) material, but the hued sapphires from Sri Lanka and Tanzania were lines are so narrow that 'forbidden' transitions in the obtained, as were a cut boule 'padparadscha' and a ferric spectrum, and hyperfine structure in the chromic cut Chatham 'padparadscha'. Similarly coloured spectrum, are seen. boule samples were also prepared to be examined. We conclude that magnetic resonance spectroscopy The stones were examined in a previously described can distinguish synthetic from natural sapphires in the magnetic resonance spectrometer4. The perpen 'padparadscha' colour range; may give a lead to the point dicular spectrum, when the DC magnetic field is of origin of naturals; and can distinguish the mode of perpendicular to the trigonal axis of the sample, is manufacture of synthetics. readily found, and was recorded for each sample: Introduction for some samples, the parallel spectrum (DC It is usually possible, by thorough microscopic magnetic field parallel to the trigonal axis) was also recorded. The microwave frequency used was in the examination, to determine whether a correctly vicinity of 9.2 GHz, and all measurements were identified 'padparadscha' variety of sapphire is carried out at room temperature. natural or synthetic. In the comparatively few cases where this is inconclusive, is there another possible test? Results In 1975, Scala and Hutton1 showed that magnetic (a) Natural material resonance spectroscopy could be used to disting Figure 1 shows the perpendicular spectra for four uish between natural (Australian) and synthetic natural stones from Sri Lanka: 'apricot', 'padpar adscha', and close to 'pink'. All specimens showed golden sapphire. In 1981, the technique was ex 3+ 2 Fe signals, and contained various amounts of tended by Anderson, Hutton and Troup , to enable 3+ 3+ the distinction between synthetic and natural blue Cr ; the concentration of Cr increased from 'apricot' to 'pink'. The variation in the relative sapphire to be made. At the Gemological Institute 3+ of America International Symposium in Los intensities of the Fe lines is due to the change in Angeles, June 1991, one of us (GJT) was asked transition probabilities of the various lines as the whether magnetic resonance would distinguish direction of the DC magnetic field with respect to between natural and synthetic 'padparadscha' sap the microwave magnetic field differs. phire. This paper gives the reply to that question. Figure 2 shows the spectra of four natural 'Padparadscha' sapphire lies somewhere between sapphires, in the appropriate colour range, from 'apricot' and 'pink' in colour, and usually has a slight Tanzania. It is seen that the Fe3+ lines are very brownish tinge also3. The main source is Sri Lanka, much broader than in the Sri Lankan cases, and that but similarly coloured stones have recently been there appears to be relatively less Cr3+. This gives found in Tanzania. Verneuil flame-fusion (boule) grounds for using magnetic resonance in helping to synthetics exist, as do flux-melt ones (Chatham). establish the point of origin of 'padparadscha'-like Strangely enough, we found it more difficult to sapphires. In a previous study2, it was already noted

D -

CJ) ..J C

3 Cr3 + Cr + 3 Fe3 + Fe3 + Fe

I I I I I I I I I I o 0.4 0.8 MAGNETIC FIELD TESLA

FigFig.. J.1. PerpendiculaPerpendicularr spectraspectra ooff 4 sapphiressapphires fromfrom SriSri Lanka.Lanka. A:A: 'apricot''apricot' sapphire;sapphire; B:B: 'pink''pink' sapphire;sapphire; C:C: 'Padparadscha''Padparadscha' (0.37(0.37 ct);ct); D:D: 'Padparadscha''Padparadscha'(0.7 (0.744 ct)ct).. JJ.. Gemm.,Gemm., 1992,1992, 2323,, 2 9999

DEEP PINK

en ..J« Z ~ en w (,) z MEDIUM PINK « z en0 w a:: (,) APRICOT I- w Z «~ :E

BLUE

j~ ____~ ______~ ____J- ____~j ____~ __~ ___~ ____~ ______IL_ ____J o 0.4 0.8 MAGNETIC FIELD TESLA

FigFig.. 22.. PerpendicularPerpendicular spectraspectra ooff 4 sapphiressapphires iinn thethe Tadparadscha'Padparadscha'' coloucolourr rangrangee frofromm Tanzania.Tanzania. 101000 JJ.. Gemm.Gemm.,, 19921992,, 2323,, 22

0 ,--

CJ) ..J ~ C Z (!) II )1( CJ) W (J Z ~ Z o B CJ) w a: (J t W Z (!) ~ :E

A \

Cr3 + Cr3 +

L o 0.4 0.8 MAGNETIC FIELD TESLA

Fig.Fig. 3.3 . PerpendicularPerpendicular spectraspectra ofof flame-fusionflame-fusion (boule)(boule) synthetics,synthetics, inin thethe appropriateappropriate colourcolour A:A : Orange;Orange; B:B : brown-red;brown-red; C:C : purple;purple; D:D : cutcut syntheticsynthetic 'Padparadscha'.'Padparadscha' . n o 8 \0 \0 ..... N N o ';-< ..... ~ f J. Gemm, 1992, 23, ~ 2 101 0.8 3+ Fe 3+ Cr 0.4 3+ Fe

"S S 3

S(flux-melt). u

3+ «J G Cr synthetic S CS

CO 3+

uChatham of

Fe o S

CJ 1)

aspectrum J3

G (U

o a ÄPerpendicular

TT 4. Fig. Z c:( ..J w CJ) c:( z z (!) w U CJ) CJ) a: o W Z c:( (!) I ::E u N N 10 10 - ~ !'l J J.':-' Gemm., 1992, 23, 2 o N 10- 2 . , 3+ C. Cr 00' and 3' 0.8 3+ F, Fe I l \ ~ll' Fb

1» 3 CJ

3 structure: c/3 a-» •5

CJCr"

Fb c

emeans FIELD H 0.4 3+

H G 3+ + Fe ~} synthetic. 3

Cr S Cr

-G " MAGNETIC -G / Chatham H

uB:

Fb 03 etl; Fb

'-J

-a 2 03 ~_._L._

+ a + -a 3 3

S3'Padparadscha' P* Fe Fe C

Jj Lanka « •-< .o 3+ + 'CSri .£ Cr 3 C/3 £ A A: B transition. L_~ G o Cr

H 'forbidden' a £ means £Parallel s

unS. bh Fig. J.J. Gemm.,Gemm., 1992,1992, 23,23, 2 103103

thatthat SriSri LankanLankan sapphiressapphires hadhad thethe narrowernarrower magnemagne tent.tent. However,However, wewe wouldwould likelike toto requoterequote tictic resonanceresonance lines.lines. Barrington's5Barrington's5 commentscomments onon thethe originaloriginal workwork ooff ScalaScala andand Hutton1 I:: 'Whilst'Whilst thethe numbernumber ofof teststests (b(b) ) Synthetic materials performedperformed maymay fallfall shortshort ofof idealideal requirementsrequirements forfor FigureFigure 3 showsshows thethe perpendicularperpendicular magneticmagnetic resoreso statisticalstatistical proof,proof, thethe uniformityuniformity ofof thethe resultsresults nancenance spectraspectra ofof fourfour bouleboule (synthetic)(synthetic) samplessamples inin achievedachieved pointpoint toto thethe factfact thatthat thisthis methodmethod isis a thethe appropriateappropriate colourcolour range,range, includingincluding a 'certified'certified worthwhileworthwhile techniquetechnique where there is doubt*, andand cutcut padparadscha:padparadscha'. ItIt willwill bebe seenseen thatthat thethe amountamount ofof otherother moremore readilyreadily availableavailable teststests areare inconclusive:inconclusive'. Fe33+ + , asas judgejudgedd fromfrom thethe signals,signals, isis veryvery significansignificant t GemmologicalGemmological identificationidentification isis basedbased onon a battery ofof lyly (1:( 1:100 100)) lessless thanthan thatthat inin thethe naturalnatural stonesstones ofof thethe teststests,, notnot oneone single test,test, andand withwith thisthis wewe agree.agree. twotwo knownknown provenances.provenances. [*[* Our Our emphasis.]emphasis.] FigureFigure 4 showsshows thethe perpendicularperpendicular spectrumspectrum ofof Finally,Finally, NassauNassau andand Valente6 speculate,speculate, inin thethe ChathamChatham synthetic.synthetic. WhileWhile Fe3+Fe3+ andand Cr3+ areare accordanceaccordance withwith theitheirr 'seven'seven typestypes ofof yellowyellow sapsap present,present, thethe lineslines areare significantlysignificantly narrowernarrower thanthan phire'phire' classification,classification, thatthat therethere maymay bebe sevenseven typestypes thosethose inin eveneven thethe bestbest qualityquality naturalnatural SriSri LankanLankan ofof 'padparadscha:'padparadscha'. TheseThese typestypes includeinclude syntheticssynthetics stone.stone. FigureFigure 5 showsshows thethe parallelparallel spectraspectra ofof thethe bestbest andand heat-treatedheat-treated materialmaterial (synthetic(synthetic andand natural).natural). 3+ SriSri LankanLankan 'padparadscha~'padparadscha', andand thethe ChathamChatham synthsynth TheThe 'no'no ironiron'' andand thereforthereforee 'no'no Fe3+'Fe ' naturalnatural etic.etic. SignificantSignificant differencesdifferences areare apparent.apparent. classificationclassification isis veryvery difficultdifficult forfor usus toto agreeagree with.with. WorkWork onon SriSri LankanLankan (and(and other)other) yellowyellow sapphiressapphires DiscussionDiscussion willwill bebe ththee subjectsubject ofof a futurefuture publication.publication. ThatThat syntheticsynthetic 'ruby','ruby', 'brown'brown sapphire'sapphire' andand 'yel'yel lowlow sapphire'sapphire' mademade byby thethe VerneuilVerneuil ~rocessprocess containcontain AcknowledgementsAcknowledgements littlelittle Fe33+ iinn comparisoncomparison ttoo CrCr 3+ wawass alreadalreadyy WeWe wouldwould liklikee ttoo thanthankk Gillian FinchFinch Inskeep,Inskeep, ooff 1 known I.. TheThe syntheticssynthetics ofof intermediateintermediate hues,hues, closeclose LankaLanka Gems,Gems, Sonoma,Sonoma, CaliforniaCalifornia 95476,95476, USA,USA, forfor toto thethe 'padparadscha''padparadscha' range,range, couldcould thereforetherefore bebe posingposing thethe originaloriginal question.question. ForFor obtainingobtaining naturalnatural expectedexpected ttoo behavebehave similarly,similarly, andand thithiss hahass beenbeen andand syntheticsynthetic materialmaterial ofof knownknown provenance,provenance, wwee verified.verified. Therefore,Therefore, a stonestone ofof 'padparadscha''padparadscha' hue,hue, wouldwould likelike toto thankthank GrantGrant andand DebbieDebbie Hamid,Hamid, ooff withwith littlelittle oror nono Fe3+,Fe3+, isis veryvery likelylikely toto bbee fromfrom a HamidHamid Bros,Bros, Melbourne,Melbourne, Victoria,Victoria, Australia;Australia; JuliaJulia boule.boule. Myers,Myers, ofof AffiliatedAffiliated Importers,Importers, Sydney,Sydney, NeNeww SouthSouth BothBoth SriSri LankanLankan andand TanzanianTanzanian naturalsnaturals showshow Wales,Wales, Australia;Australia; andand thethe USUS suppliers,suppliers, Chatham,Chatham, comparativelycomparatively largelarge Fe3+Fe3+ signals:signals: thethe Fe3+Fe3+ concenconcen NeNeww YorkYork 1003610036 forfor theirtheir 'padparadscha','padparadscha', andand NewNew trationtration isis obviouslyobviously largerlarger inin ththee TanzaniaTanzaniann stones,stones, Era,Era, GrassGrass Valley,Valley, California 9594595945 forfor thethe TanzaTanza bothboth becausebecause ofof signalsignal heightheight andand ofof thethe muchmuch niannian material;material; andand E.E. GaminiGamini Zoysa,Zoysa, Mt.Mt. Lavinia,Lavinia, greatergreater lineline width.width. AsAs pointedpointed outout earlier,earlier, thesethese SriSri Lanka,Lanka, forfor 'padparadscha''padparadscha' (natural).(natural). propertiesproperties cancan helphelp inin ththee determinationdetermination ofof placeplace ooff ongm.origin. ReferencesReferences TheThe ChathamChatham syntheticsynthetic isis anan extremelyextremely goodgood I.1. Scala,Scala, C.M.,C.M., Hutton,Hutton, D.R.,D.R., 1975.1975. A definitivedefinitive testtest foforr goldengolden syntheticsynthetic 'simulant''simulant' ofof thethe naturalnatural spectrum.spectrum. AsAs sapphires,sapphires, Australian Gemmologist, 16,16, 160.160. 2 2.2. Anderson,Anderson, CaroleCarole M.,M., Hutton,_Hutton, D.R.,D.R., Troup,Troup, G.].,G.J., 19811981.. pointed out in an earlier work , it is too good, pointed out in an earlier work , it is too good, MagneticMagnetic resonance resonance distinction distinction between between synthetic synthetic and natural and natu becausebecause ofof thethe sharpnesssharpness ofof thethe lines,lines, whichwhich givegive anan blueral sapphire. blue sapphire. Australian Australian Gemmologist, Gemmologist, 14, 87. 14, 87. indicationindication ofof crystalcrystal latticelattice perfection.perfection. A carefulcareful 3.3. Crowningshield,Crowningshield, R.,R., 1983.1983. Padparadscha:Padparadscha: what'swhat's inin a name?name? comparisoncomparison withwith thethe bestbest SriSri LankanLankan 'padparads'padparads Gems and Gemology, 19,19, 30.30. 4. Hutton, D.R., Seed, T.J., 1966. Crystal rotation and orienta cha'cha' spectrumspectrum willwill showshow thatthat thethe lineslines ofof thethe 4. Hutton, D.R., Seed, T.J., 1966. Crystal rotation and orientation for tionElectron for ElectronSpin Resonance Spin Resonance Studies. Journal Studies. of Scientific Journal of Scien ChathamChatham stonestone areare muchmuch narrower.narrower. AsAs inin previousprevious Instruments,tific Instruments, 43, 949-50. 43, 949-50. 2 work2, forfor confirmation,confirmation, itit maymay bebe necessarynecessary toto gogo toto 5.5. Barrington,Barrington, E.N.,E.N., 1975.1975. ElectromagneticElectromagnetic resonanceresonance inin yellowyellow thethe parallelparallel spectrum;spectrum; thethe comparisoncomparison isis givengiven inin sapphires.sapphires. Australian Gemmologist, 12,12, 159.159. FigureFigure 5,5, betweebetweenn thethe Chatham,Chatham, andand thethe besbestt SriSri 6.6. Nassau,Nassau, K.K.,, ValenteValente,, G.K.G.K.,, 1987.1987. ThThee sevenseven typetypess ofof yellowyellow sapphiresapphire andand theirtheir stabilitystability toto light.light. Gems and Gemology, 222222.. LankanLankan 'padparadscha:'padparadscha'. Admittedly,Admittedly, thethe numbernumber ofof stonesstones studiedstudied hashas beenbeen small,small, butbut thethe resultsresults areare remarkablyremarkably consis-consis [Manuscript[Manuscript receivedreceived 30 30 October October /99/.] 1991. ] 104 J. Gemm., 1992, 23, 2

Gemmological Abstracts

ASTRIC, R., MERIGOUX, H., ZECCHINI, P., BRACE WELL, H., 1991. Gems around Australia, 1991. Etude théorique de l'aspect d'un Part 5. Australian Gemmologist, 17, 11, 454-6, 5 diamant taille brillant en fonction de ses figs. paramètres de taille. Revue de Gemmologie, The Bracewells, continuing their long tour, 107, reached Kununurra some 200km north of the The brilliant cut for diamonds is described Argyle diamond mine and home of the red-striped with notes on cutting parameters. Various siliceous argillite known as zebra stone. To Mrs versions of the brilliant cut are compared. Bracewell's surprise the difficult problem of M.O'D. polishing this strange form of sandstone is over come by using a spray can of Dulux lacquer. BOSSHART, G., 1991. Les emeraudes de Prehnite and quartz were found in this area but were Colombie [continuation]. Revue de scarcely worth extracting. The gold area of Hall's Gemmologie, 107, 7-12, 9 figs in colour. Creek, 370km south, billed a natural 'China Wall'of French version of a paper first published in quartz as a tourist attraction, while Geiki Gorge to German. M.O'D. the west yielded some rather disappointing calcite. R.K.M. BOWERSOX, G., SNEE, L.W., FOORD, E.E., SEAL II, R.R., 1991. Emeralds in the Panjshir BRACE WELL, H., 1991. Gems around Australia, Valley, Afghanistan. Gems & Gemology, 27, 1, Part 6. Australian Gemmologist, 17, 12, 502-3, 2 26-39, 19 figs. figs and map. A nicely illustrated paper on the emeralds and Describes pearling and shell industry at Broome mines of a valley high in the Hindu Kush and its environs, including culture of large pearls mountains north of Kabul. Access is very since 1956 in Kuri Bay. Names on map are illegible. difficult, and the unsafe adit mines are high in R.K.M. the rugged limestone mountains several thousand feet above the villages. The emerald BRACEWELL, H., 1991. Faded amethyst. (Letter). crystals are often colour-zoned with pale Australian Gemmologist, 17, 12, 525. centres, most about 5 carats, but larger stones Mrs Bracewell reports on a pair of amethysts are found, including one of 190 carats. Crystal which were mislaid in a dark cupboard for three habit normal for emerald, but often eroded or years and faded to almost colourless. R. K. M. etched. RIs (e) 1.574 and (o) 1.580 variable but generally high; SG 2.68 to 2.74; no reaction to BRAUNS, S., 1991. Nya Fyndorter under 1980- UV; pink or orange under Chelsea filter; Talet. Gem Bulletinen, 1/91,7-9. inclusions numerous, often multi-phased (brine, Brief details of gemstone finds during the gas, and several different mineral crystals in 1980s are given. Adapted from a paper in Gems cavities reminiscent of the jagged ones of Muzo), & Gemology 1990. M.O'D. solid crystals include limonite, pyrite, a carbonate and feldspar. Most output is exported BRIGHTMAN, R., 1991. Gem quality almandine by mule-train to Pakistan where it is almost garnets from Antarctica. Australian Gemmologist, certainly oiled. The multi-crystal content of 17, 11,470-3,2 maps, 6 figs. three-phase inclusions identifies provenance of Crystal fragments collected in the Rauer Islands, these emeralds. Prydz Bay, Antarctica, were found to be dark red Area is thought to be producing about $10 almndine garnet, RI 1.770 to 1.782, SG 3.955 to million rough a year, cut stones available world 4.040. Thin pieces had normal absorption spectra. wide. With end of the Russian war production is Inclusions of rutile (?) silk, other crystals and large expected to increase. R.K.M. healed finger-print cracks were seen. Occurrence is unlikely to be exploited since there is an embargo on commercial mining. R. K. M. J. Gemm., 1992, 23, 2 105

BROWN, G., 1991. Quality assessment - to be or magnification while immersed. Many imperfec not to be? GAA Presidential Address. tions, pock-marks, colour concentration at facet and Australian Gemmologist, 17,10,393-6. girdle edges belied the good face-up colour. Au The President suggests that quality thorssay'Caveatemptor!' R.K.M. assessment and valuation should be taught in gemmology. [The idea is not new but its BROWN, G., HAMID, D., 1991. A faded achievement is set with considerable difficulties: amethyst necklace. Australian Gemmologist, e.g. who is to decide what constitutes fine 17, 10, 426-8, 4 figs. colour; who to fix prices and at what levels? How A necklace of tumbled light amethyst beads do impoverished schools acquire the fine stones faded badly after prolonged exposure to window to teach quality? Valuation is dependent on lighting and sunlight. A few beads shielded by many years of buying and selling by people the display case did not change but the rest had prepared to back their judgement with hard changed to pale citrine or colourless. [This fade cash. Colour and quality are very much a matter factor in these stones appears to vary of individual opinion and taste.] RK.M. considerably with the origin of the amethyst, rather as does its reaction to heat. Some heat BROWN, G., 1991. Corallium precious corals. must have been involved here but this would Wahroongai News, 25, 11,28-32,2 figs. probably have affected the covered section too if A short paper based on researches of Professor it was responsible for the change.] RK.M. Rick Gregg of University of Hawaii, dealing with C. rubrum, C. secundum, C. konojoi, C. japonicum, C. BROWN, G., KELLY, S.M.B., 1991. Lechleitner nobile, C. elatius, C. regale and a C. sp, nov: and coated corundums. Australian Gemmologist, principally concerned with the possible exhaustion 17,10,408-11,14 figs. of supplies of these precious corals in the next Flux-coated seeds of synthetic or natural decade or so, due to over-fishing. RK.M. corundum have been produced by Lechleitner since 1983. 12 specimens of rough and finished BROWN,G., 1991.Treated Andamookamatrix opal. gems were examined, gemmological properties Gems & Gemology, 27, 2,100-6,11 figs. corresponded with those of natural corundums, This carbon impregnated opal appeared in the but wispy veils, reticulated fractures in the 1950s [offered in London as 'completely natural synthetic coating and curved colour striae in the black opal']. The matrix opal is shaped and synthetic seeds were easily seen. [The excellent polished, then heated to 105°Cin a slightly acid 20% colour illustrations here make it obvious that the solution of glucose and lactose (1:4) until sugars seeds are crudely pre-formed and one would solidify and darken. Stones are broken out and then expect some patchy removal of the colour layer boiled in concentrated sulphuric acid for five hours, when finishing.] RK.M. and washed for several hours to eliminate residual acid. A final polish has to be light to avoid removing BROWN, G., KELLY, S.M.B., BRACEWELL, H., the shallow layer of carbon. [In London the first 1991. Gemmology study reports. Australian parcels were bought at high prices with a view to Gemmologist, 17,10,417-25,31 figs. repolishing, a move which failed miserably]. Reports on plastic imitation of walrus tusk RK.M. scrimshaw with blebs of plastic in the 'engraved' lines; metz heshi devitrified glass by Iimori of BROWN, G., 1991. jewfish pearl. (Letter). Austra Tokyo possibly imitating malachite; star ruby lian Gemmologist, 17, 12,525, 1 fig. and sapphire imitations achieved by ruling flat A 'pearl' the size of a small human skull is base of synthetic corundums with lines illustrated, but comes from a sperm-whale, and is intersecting at 120°; Czochralski pulled lithium identified as an otolith (inner-ear bone). That of the niobate in various colours made to imitate fancy jew-fish(jewel-fish)grows to about 4cm. RK.M. diamonds, RI 2.20 to 2.30, high DR and high dispersion 0.120 make distinction simple, SG BROWN, G., BEATTIE, R., 1991. A new surface also high (4.64), included bubbles. Basal and diffusion-treated sapphire. Australian Gemmolog rhombohedral parting were seen in yellow ist, 17, 11,457-9,10 figs. sapphire crystal from Queensland; massive rutile One parcel of Kanchanaburi sapphires purch from Mt Perry, Queensland, resembles hematite ased in Thailand for recutting in Australia, con when polished; a carved opal doublet was from sisted entirely of rather crudely surface-diffusion Lightning Ridge; profiled bubbles as in synthetic treated stones which lost colour when repolished. spinel [and synthetic rubies] found in Verneuil Easily recognized after discovery by low-power synthetic rutile; a jelly opal had been 'improved' 106 J. Gemm., 1992, 23, 2

by backing with black paint; zebra stripes in the colour being attributed to nitrogen. In amethyst are discussed and illustrated; a bakélite general synthetic single crystals of this type are imitation of amber had been carved with a drill, sliced for industrial products rather than used in SG and RI too high for amber; influx of South jewellery. M.O'D. Africans to Australia is bringing Zambian, [Abstractor's note: Indiaqua now appears annually rather than quarterly.] Sandawana and other African emeralds in increasing numbers, excellent photomicrographs CHIPENKO, G.V., et al., 1990. A new habitus of Zambian inclusions are printed. R.K.M. type of diamond crystal. Doklady Akademii Nauk SSSR, 312, 1990, 876-9 (in Russian). BROWN, G., KELLY, S.M.B., BRACEWELL, H., Abstr. Industrial Diamond Review, 51, 1991, 1991. Gemmological study club lab reports. 148. Australian Gemmologist, 17,11, 475-8, 15 figs. Describes the production of a new synthetic Green smithsonite; Gilson triplet opals; inclu diamond crystal habit by the recrystallization sions in synthetic spinel; imitation pearl made from method. The major factors influencing the fish jaw-bone; faceted sodalite; South African 'jade' growth of this form of diamond crystal are found (hydrogrossular garnet); Mississippi mussel nacre to be temperature, rate of transfer of carbon and cabochons and agatized dinosaur bone are ex amount of nitrogen present. The crystals are amined and reported upon. R. K. M. characterized by the predominance of an unusual combination of forms, mainly of the BROWN, G., KELLY, S.M.B., BRACEWELL, H., (111), (110) and (311) forms. E.S. 1991. Gemmology study club reports. Australian Gemmologist, 17,12, 526-31,16 figs. COENRAADS, R.R., VAN DER GRAAF, R., 1991. Deals with heated cornelian known as Tires of An occurrence of gem garnets from Horse Mt Warning'; cat's-eye emerald; a green doublet Gully in New England gemfields, New South which seemed to have quartz crown and natural Wales. Australian Gemmologist, 17, 10, 412- beryl base [cutters have been known to dop doub 15, map and 4 figs. lets upside down by accident]; an imitation star Pyrope-almandines of red to purplish colours sapphire doublet [?] which had both dome and base have been found in association with sapphires of cobalt blue spinel, and three intersecting sets of and other gems, some with slight tendency to scored lines at its back; a dubious Chinese turquoise colour change to orange red in incandescent that was proved to be natural; a new focusing pen light. RIs vary from 1.759 to 1.772 in the seven torch useful for microscopy; a new imitation jade stones examined, euhedral crystals probably of from Kowloon identified as dyed calcite coated with apatite were included. [A small inset map has wax; a natural sapphire/synthetic ruby doublet, set towns of Inverell and Glen Innes transposed.] to conceal the girdle, which was identified by R.K.M. careful scrutiny by binocular microscope; and a large crystal of ekanite from Ratnapura which EDIRIWEERA, R.N., PERERA, S.I., WEERASINGHE, weighed 210 grams. R.K.M. W., 1991. Method of creating required atmos pheric conditions within crucibles placed inside a CASSEDANNE, J.-P., ALVES, J.-N., 1991. furnace. Australian Gemmologist, 17, 11, 443-5, 3 L'aigue-marine au Bresil-1. Revue de figs. Gemmologie, 107, 13-16, 7 photos (2 in A simple and inexpensive way to pipe oxygen or colour), 2 maps. reducing gases through a furnace base to surround First part of a paper on Brazilian aquamarine geuda sapphire or other stones during heat treat describing pegmatitic and alluvial occurrences ment. R.K.M. with notes on the general geomorphology of the areas described. M.O'D. FRYER, C.W., Ed., CROWNINGSHIELD, R., HARGETT, D., HURWIT, K.N., 1991. Gem CAVENEY, R.J., 1991. De Beers Research Trade Lab notes. Gems & Gemology, 27, 1, Laboratory Report 1991. Indiaqua, 1991, 40-5, 18 figs. 241-6, 22 figs (21 in colour). An alexandrite had figures and initials The Laboratory has synthesized a 14.2 ct scratched just below the girdle, natural industrial diamond crystal of good quality which turquoise-coloured chalcedony from Mexico is is thought to be the largest yet to be to be marketed; a 1.07 ct grey-blue diamond was manufactured. Over 500 hours of high exceptionally electro-conductive; a sharply temperature/high pressure running was needed zoned emerald was suspected as doublet but a to complete the synthesis. The crystal is yellow, fracture crossing the 'join' proved otherwise; a J. Gemm., 1992, 23, 2 107

rare banded Afghan lapis lazuli was seen. seed with a blue outline; a violet spinel became Iolite and coloured moonstone necklaces pinkish purple in incandescent light and fluoresced were seen and considered unusual; natural chalky green in LUV; a cobalt blue synthetic spinel bronze pearl reported fished from La Paz area of had veil inclusions possibly due to strain; a blue Baja, California, suggest that a naturally topaz had 'lightning' streaks of damage due to destroyed former source has regenerated; 17mm radiation treatment; a radio-active low zircon cultured pearls seen by East Coast Lab, one [green?] emitted 0.4 milliroentgens per hour and thinly coated, the other exceptionally thick would probably be unsafe to wear, no uniaxial nacre. interference figure could be obtained. R. K. M. A large antique cabochon emerald and diamond pendant had been enlarged by adding FRYER, W., CROWNINGSHIELD, R., HARGETT, D., diamond set cultured pearls of much later date; MOSES, T., HURWIT, K., KANE, R.E., 1991. Gem Verneuil ruby had cut 'natural' crystal prism, Trade Lab notes. Gems& Gemology, 27, 3, 174-9. pinacoid and rhombohedral faces; an orange-red A rare hexagonal pit (combined positive and flux-grown synthetic corundum had straight negative trigon) and a quite extraordinary hexagon banding [gemmologists need to be wary of all al acicular tube in diamond are illustrated and kinds of deception]. explained; a type lib blue diamond exhibited A weak star sapphire revealed surface natural radiation stains on its girdle - first time this diffusion treatment for both star and colour has been noted. enhancement, the dual surface diffusion process A 15.17ct 'accidental' sea-water tissue-nucleated has not been a commercial success, it is cultured pearl, is probably the largest so far seen - it questioned whether heat-treatment of star is thought that none are in deliberate production; an material to produce clean and facetable crystals unusual greenish-black necklace of natural pearls is depleting supply of star stones; six calibrated had been dyed; another black necklace had been blue synthetic sapphires had unusual triangular dyed except for two pearls which were naturally two-phased inclusions. R.K.M. black and appeared brownish on immersion and gave a chalky-green colour under LUV; a bullet- FRYER, C.W., CROWNINGSHIELD, R., HARGETT, shaped cultured pearl of natural colour had a deep D., MOSES, T., HURWIT, K., KANE, R.E., 1991. hole in its back which was partly filled by another Gem Trade lab notes. Gems & Gemology, 27, 2, natural black cultured pearl, author speculates on 108-14,19 figs. how this could occur. An amber necklace 'washed' in alcohol had A pendant earclip had a half-drilled pearl which developed a white 'bloom' and lost its polish; was 'smooth to the teeth' and identified initially as electron-treated coloured diamonds are recently imitation, but X-rays showed it to be cultured more numerous and a 37ct yellow was identified as which had been worked (polished). The Tucson irradiated by colour zoning near the culet; another Show offered white mabe pearls with strong pink old-cut yellow diamond was found mounted in an over-tones due to a plastic core with a reflecting art nouveau brooch, but was again a treated stone lacquer coating; a pair of matching mabe also had although the brooch apparently dated from before lacquer on their inner surfaces but one lacked a solid the treatment was available; a 'filled' crack in a insert. diamond had anomalous orange and green flashes A pendant drop of diamonds and 94 calibre against dark ground illumination [these colours rubies contained only 8 natural rubies, the rest would surely vary with the width of the crack?]; a being early synthetics, possibly Geneva rubies cut light green octahedron was a predicted pale yellow from pea-sized boules, pre-Verneuil synthesis. A when cut, the GR1 absorption band was present in final note is made of the resurgence of diffusion the green coating, but was lost when that was cut treated sapphires since early 1990; the trend con away; two instances of irradiation staining in etch tinued in 1991 and some large ones have been found cavities in cut diamonds are illustrated and theo in important jewellery. Writer advises all sapphire rized upon. be checked by immersion as the safest way to detect A cultured pearl with nacre covering only half the this colour faking. R.K.M. bead was examined, the other half was pinkish brown and non-nacreous for reasons unknown; GEHRMANN, A.L., 1991. Der Granatenkogel 'rose-bud' pearls forming a necklace were typical (3.304mm). Mineralien Welt, 2, 4, 53-6, 9 products of the American fresh-water Unio mussel; photos (6 in colour), 1 map. a pair of cultured blister pearls were found to be Crystals of almandine are found on the plugged, and therefore assembled, when X-rayed. Granatenkogel in the Otztaler Alps of the An early flux-grown synthetic ruby had a natural Austrian Tirol. Well-formed crystals up to 5cm 108108 J.J. Gemm.,Gemm., 1992,1992,23, 23, 2

areare reportedreported thoughthough mostmost areare notnot ofof gemgem quality.quality. numbernumber ofof sodalitesodalite groupgroup minerals)minerals) ttoo M.O'D.M.O'D. tetragonal.tetragonal. LargeLarge Si-O-BeSi-O-Be anglesangles areare typicaltypical ooff thethe structurestructure andand thesethese anglesangles areare largerlarger thanthan GILGIL IBARGUCHI,IBARGUCHI, J.I.,J.I., MENDIA,MENDIA, M.,M., GIRARDEAU,GIRARDEAU, thosethose inin helvitehelvite groupgroup minerals.minerals. ThermalThermal J.,J., 1991.1991. Mg-Mg- andand Cr-richCr-rich staurolitestaurolite andand CrCr- expansionexpansion isis controlledcontrolled largelylargely byby rotationsrotations ooff richrich kyanitekyanite inin high-pressurehigh-pressure ultrabasicultrabasic rocksrocks thethe T07D44 tetrahedra.tetrahedra. TheThe thermalthermal expansionexpansion waswas (Cabo(Cabo Ortegal,Ortegal, northnorth westernwestern Spain).Spain). modelledmodelled usingusing thethe DLS program,program, thethe crystalcrystal American Mineralogist, 76,76, 501-11,501-11, 9 figs.figs. structurestructure waswas obtainedobtained byby usingusing anan automatedautomated GreenGreen pleochroismpleochroism ofof staurolitestaurolite andand blueblue singlesingle crystalcrystal four-clrclefour-circle X-rayX-ray diffractometerdiffractometer pleochroismpleochroism ofof kyanitekyanite (in(in non-gemnon-gem crystalscrystals usingusing MoKaMoKa radiation.radiation. M.O'D.M.O'D. fromfrom thethe CaboCabo OrtegalOrtegal complexcomplex inin northnorth westernwestern Spain)Spain) areare attributedattributed toto substitutionsubstitution ooff HENN,HENN, V.,U., 1991.1991. GeschliffenerGeschliffener AegirinAegirin unundd AlAl byby CrCr inin octahedraloctahedral sites.sites. ItIt isis suggestedsuggested thatthat Aegirin-augitAegirin-augit ausaus Norwegen.Norwegen. (Cuttable(Cuttable Mg-Mg- andand Cr-richCr-rich staurolitestaurolite andand Cr-richCr-rich kyanitekyanite aegirineaegirine andand aegirineaegirineaugit augitee fromfrom Norway.)Norway.) werewere stablestable throughthrough ecologiticecologitic composition.composition. ZeitschriJtZeitschrift der Deutschen GemmologischenGemmologischen AlthoughAlthough thethe CrCr contentscontents ofof kyanitekyanite anandd GesellschaJt,Gesellschaft, 40,40 , 1,1, 69-71,69-71, 1 graph,graph, 1 table,table, staurolitestaurolite couldcould indicateindicate Cr-richCr-rich bulkbulk bib!.bibl. compositioncomposition thethe occurrenceoccurrence ofof smallsmall colourlesscolourless TheThe materialmaterial comescomes fromfrom thethe LangesundLangesund Cr-poorCr-poor kyanitekyanite includedincluded inin matrixmatrix mineralsminerals andand fjordfjord inin southernsouthern NorwayNorway andand isis a mixedmixed mineralmineral blueblue Cr-richCr-rich matrixmatrix kyaniteskyanites suggestssuggests increasingincreasing betweenbetween diopsidediopside andand acmite.acmite. PhysicalPhysical CrCr substitutionsubstitution inin kyanitekyanite withwith increasingincreasing propertiesproperties areare given.given. E.SE.S.. pressurepressure andand temperaturetemperature.. M.O'D.M.O'D. HENN,HENN, U.,U., 1991.1991. Burma-typeBurma-type rubiesrubies fromfrom Vietnam.Vietnam . GRIGG,GRIGG, R.W.,R.W., BROWN,BROWN, G.,G., 1991.1991. TasmanianTasmanian Australian Gemmologist, 17,17 ,12,505-9, 12, 505-9 ,10 10 figs figs and an d gemgem corals.corals. Australian Gemmologist, 17,17, 10,10 , map.map. 399-404,399-404, 4242 figs.figs. AnotherAnother reportreport onon thethe heavilyheavily includedincluded BurmaBurma SeveralSeveral speciesspecies ofof bamboo,bamboo, goldgold andand blackblack typetype rubiesrubies foundfound inin marble,marble, northwestnorthwest ofof HanoiHanoi varietiesvarieties ofof coralcoral havehave beenbeen accidentallyaccidentally trawledtrawled nearnear thethe ChinaChina border.border. ConstantsConstants areare normal,normal, offoff SouthSouth TasmaniaTasmania whilewhile catchingcatching deepdeep waterwater twinningtwinning moremore commoncommon andand solidsolid inclusioninclusionss lessless soso fishfish knownknown asas 'orange'orange roughy'roughy'.. Morphology,Morphology, thanthan inin BurmeseBurmese stones.stones. R.K.M.R. K.M. hand-lenshand-lens characteristicscharacteristics andand gemmologicalgemmological propertiepropertiess areare givengiven.. Trawl-neTrawl-nett damagdamagee iiss costlycostly HENNHENN,, V.,U., BANKBANK,, H.H.,, 1991.1991. EpidoEpidott vovonn derder anandd thesthesee findsfinds araree nonott welcomewelcomedd bbyy fishingfishing KnappenwanKnappenwandd iimm Vntersulzbachtal,Untersulzbachtal, fraternity.fraternity. R.K.M.R.K.M. ÖsterreichOsterreich.. (Epidot(Epidotee fromfrom ththee KnappenwandKnappenwand iinn ththee UntersulzbacVntersulzbachh vallevalleyy iinn Austria.)Austria.) HÄNNIHANNI,, H.A.H.A.,, SCHMETZER,SCHMETZER, K.K.,, 1991.1991. NeNeww rubiesrubies ZeitschriftZeitschriJt der Deutschen GemmologischenGemmologischen frofromm ththee MorogorMorogoroo areaarea,, TanzaniaTanzania.. Gems & GesellschaJt,40,Gesellschaft, 40 , 1,1 ,1-9, 1-9 ,13 13 figs, figs , 22 tables, tables ,bib!. bibl . Gemology, 27,27 , 3,3 , 156-67,156-67 , 1616 figs. figs . ThThee besbestt knowknownn sourcesource ooff epidotepidotee iinn EuropeEurope A neneww findfind ofof reredd toto blubluee spinelsspinels containedcontained aboutabout iiss ththee KnappenwanKnappenwandd iinn ththee vallevalleyy ooff ththee lowerlower 10%10% ooff cabochocabochonn qualitqualityy rubyruby,, a fewfew ofof whicwhichh wouldwould SulzSulz iinn AustriaAustria.. ThiThiss hahass beebeenn workeworkedd forfor 125125 facet.facet. TreaclTreaclyy swirlsswirls andand angulaangularr zoninzoningg werweree seenseen yearyearss anandd frofromm timtimee ttoo timtimee crystalscrystals ooff cuttablecuttable anandd a fefeww starsstars werweree cutcut.. SomSomee crystalcrystalss pseudopseudo- qualitqualityy araree foundfound.. SomeSome ooff thithiss materiamateriall hahass octahedral with angles more acute than in spinel. octahedral with angles more acute than in spinel. beebeenn examined:examined: nnxx = 1.731-1.738,1.731-1.738, nnyy = 1.748-1.748- TwiTwinn lamellalamellaee anandd coloucolourr planeplaness paralleparallell witwithh ththee 1.7531.753,, nzz = 1.761-1.7731.761-1.773.. DDRR 0.031-0.0360.031-0.036,, SSGG rhombohedrarhombohedrall facesfaces,, negativnegativee crystalscrystals,, fissures,fissures, 3.37-3.443.37-3.44.. TypicaTypicall inclusioninclusionss araree byssolite,byssolite, rutilrutilee silksilk,, apatitapatitee anandd spinespinell inclusioninclusionss werweree alsalsoo calcitecalcite,, apatitapatitee aass welwelll aass liquiliquidd inclusioninclusionss anandd foundfound.. ThesThesee stonestoness resemblresemblee BurmBurmaa materiamateriall iinn growtgrowthh zoningzoning.. E.SE.S.. typtypee whilwhilee earlieearlierr MorogorMorogoroo rubierubiess ddoo notnot.. R.K.M.R.K.M. HENNHENN,, U.V.,, BANKBANK,, H.H.,, SCHUPPSCHUPP,, F.J.F.J.,, 1991.1991 . HASSANHASSAN,, I.I.,, GRUNDYGRUNDY,, H.D.H.D.,, 19911991.. ThThee crystacrystall RubinRubinee auauss VietnamVietnam.. (Rubie(Rubiess frofromm Vietnam.)Vietnam.) structurstructuree anandd thermathermall expansioexpansionn ooff tugtupitetugtupite ZeitschriftZeitschriJt der Deutschen GemmologischenGemmologischen NNa[AlzBezSi80Z4]Clz.a [A 12Be2Si8024] C12. Canadian Mineralogist, Gesellschaft,GesellschaJt, 40,40 , 1,25-8,81, 25-8, 8 figs, figs , bib!.bibl . 2929,, 385-90385-90,, 2 figs.figs. ThThee rubierubiess seeseemm ttoo comcomee frofromm ththee HuangHuang TugtupiteTugtupite,, a sodalitsodalitee grougroupp mineralmineral,, hahass fullyfully LieLienn SoSonn ProvinceProvince,, abouaboutt 250k250krnm north-wesnorth-westt ooff ordereorderedd frameworframeworkk T cationcationss [wher[wheree TT HanoiHanoi.. ThThee coloucolourr ooff ththee rougroughh crystalcrystalss variesvaries representrepresentss AlA 133++ , Be2z+ anandd Si4+4+],], ththee orderorder frofromm palpalee reredd ttoo redred,, sometimesometimess witwithh a distincdistinctt lowerinloweringg ththee symmetrsymmetryy frofromm cubicubicc (a(ass iinn aa violeviolett huehue.. WeaWeakk pleochroismpleochroism,, reredd ttoo yellowish-yellowish- J. Gemm., 1992,23,2 109

red. Physical data lie within known range of A diagram suggests that quartz is deposited, corundum. The colour is caused by Cr3. rather in the order found in a natural geode, at the Inclusions are healing cracks, fluid inclusions, hotter end of an autoclave instead of the cooler end; lamellar twinning, hollow tubes, rutile dust, cristobalite was the source powder. R. K. M. rounded crystal inclusions, cracks «and growth lines. E.S. KAMMERLING, R.C., KOIVULA, J.I., 1991. Identifying features of filled diamonds in HLAING, U.T., 1991. A new Myanmar ruby de review. South African Gemmologist, 5, 2, 10- posit. Australian Gemmologist, 17, 12, 509-10, 1 16,7 figs (2 in colour). «g. Signs of filled diamonds are described and The first published report of rubies from Mong illustrated. M.O'D. Hsu area of Shan State, S.E. Myanmar [Burma]; four stones examined were rather poor. R. K. M. KAMMERLING, R.C., KOIVULA, J.I., 1991. Rough grinding pavilions for intentional light HODGKINSON, A., 1991. Synthetic red spinel. Au scattering. South African Gemmologist, 5, 2, stralian Gemmologist, 17, 11,466-8,1 fig. 17-21, 3 figs in colour. Inspired by queries about identifying flawless red Rough grinding of the base in some synthetic spinels, the paper offers answers based on the stones causes light scattering and a more natural blue/red crossed filter technique advocated by appearance when stones are examined face up. Anderson to detect chrome fluorescence and now Ruby and blue synthetic spinel are illustrated. offered in solid filter form by McCrone Instru M.O'D. ments. [Many red spinels do not fluoresce and I doubt if this paper necessarily solves the problem of KAMMERLING, R.C., KOIVULA, J.I., FRITSCH, E., distinguishing them. ] R. K. M. 1991. Characterization of a so-called 'Recon structed lapis lazuli'. Australian Gemmologist, 17, HOLZHEY, G., 1991. Feueropal aus 11, 450-3, 3 figs. Aleksejewskoje, Kasachische SSR, UdSSR - A convincing new imitation consisting of barium ein Beitrag zu vergleichenden gemmologisch- sulphate with pyrite inclusions, bonded in a polym mineralogischen Untersuchungen er, was translucent to a powerful light placed behind it. Natural lapis would have been opaque. SG 2.31 is mikrokristalliner Si02 Minerale. (Fire opal from Aleksejewskoje, Kazakstan in the USSR low, while RI 1 55 is too high for true lapis. a contribution to comparative 'Reconstructed lapis lazuli' is a misnomer. [Darker gemmological-mineralogical examinations of blue around pyrite inclusions normal to most natural lapis seems to be absent. ] R. K. M. microcrystalline Si02 minerals.) Zeitschrift der Deutschen Gemmologischen Gesellschaft, 40, 1, 11-23, 2 colour photographs 5 KAMMERLING, R.C., KOIVULA, J.I., FRITSCH, E., photomicrographs, 3 graphs, 1 table bibl. 1991. Plastic imitation opals purchased in Thai The Russian fire opals from Aleksejewskoje land. Australian Gemmologist, 17,12,498-501. are compared with those from Zimapan, Bracelets of plastic imitation opals were liberally infested with gas bubbles and owed their colour- Mexico. RI (1.448) and SG (2.06) are average. play to fragments of film or laminate, they gave The submicroscopic structure with a system of broad bands at 560, 608 and 650nm plus a back cracks can be compared with other ground of fine lines through the whole spectrum. microcrystalline Si0 minerals such as agates 2 Superficially similar to Slocum Stone. R.K.M. and point to a primary gel-like state of silicic acid. The trace elements show a higher content of non-volatile constituents suggesting a granitic KAMMERLING, R.C., KOIVULA, J.I., FRYER, host for the fire opals. E.S. C.W., 1991. An unusual imitation jade carving. Zeltschrift der Deutschen HOOVER, D.B., 1991. Peridot or sinhalite? (Letter). Gemmologischen Gesellschaft, 40, 1, 29-32, 3 Australian Gemmologist, 17,12, 524. photographs, 3 photomicrographs, bibl. On detection of sinhalite by its greater thermal The jade carving - a sphere - was bought in conductivity; further applications of the method are the jade market in Kowloon, Hong Kong. It is discussed. R.K.M. pierced and carved, weighs 933.50 ct and ranges from 52.0-53.3mm in diameter. It is opaque HOSAKA, H., 1991. Observations on hydrothermal- except in thin edges, where it is semitransparent. ly synthesized massive agate-like crystals. Austra Colour varies from dark reddish-brown to lian Gemmologist, 17,12, 503-5, 6 figs. medium yellowish-brown to vivid dark 110110 J.J. Gemm.,Gemm., 1992,1992,23, 23, 2

yellowish-green.yellowish-green. ItIt waswas foundfound toto bebe a rockrock nordstrandite,nordstrandite, newnew inin corundum;corundum; phlogopitephlogopite micamica consistingconsisting ofof calcitecalcite andand lesserlesser amountsamounts ofof waswas alsoalso seen.seen. RubiesRubies ofof similarsimilar typetype areare foundfound serpentine,serpentine, possiblypossibly a serpentineserpentine marblemarble calledcalled acrossacross thethe borderborder inin ChinaChina andand possiblypossibly inin Laos.Laos. ophicalcite.ophicalcite. TheThe spheresphere hadhad beenbeen selectivelyselectively FurtherFurther gemgem areasareas areare expectedexpected andand thethe wholewhole dyeddyed brownbrown inin thethe calcitecalcite areasareas andand greengreen inin thethe regionregion couldcould becomebecome a significantsignificant sourcesource ofof ruby.ruby. serpentineserpentine areas,areas, ththee wholewhole piecepiece beingbeing waxwax oror IllustrationsIllustrations onon neutralneutral backgroundsbackgrounds seemseem toto depictdepict paraffiparaffinn coated.coated. E.S.E.S. thethe colourcolour andand qualityquality nicelynicely.. R.K.M.R. K. M. KEELING, 1991. Review of a new theory on KAMMERLING,KAMMERLING, RC.,R.C., KOIVULAKorVULA,, J.I.,J.I., KANE,KANE, RE.,R.E., KEELING, J.L.,J.L., 1991. Review of a new theory on emerald formation in schist deposits. Australian MADDISON,MADDISON, P.,P., SHIGLEY,SHIGLEY, J.E.,J.E., FRITSCH,FRITSCH, E.,E., emerald formation in schist deposits. Australian 1991.1991. FractureFracture filling ofof emeralds.emeralds. OpticonOpticon andand Gemmologist, 17,17,11,440-2 11,440-2.. traditionaltraditional 'oils:'oils'. GemsGems& & Gemology, 27,27 ,2, 2 ,70-85, 70-85 , RecentRecent studiesstudies ofof HabachtalHabachtal (Austria)(Austria) andand LeydsLeyds- 1717 figs. dorpdorp (Transvaal)(Transvaal) emeraldsemeralds byby GrundmannGrundmann andand ComparesCompares ththee epoxyepoxy resinresin 'Opticon''Opticon' withwith CanadaCanada MorteaniMorteani ofof MunichMunich UniversityUniversity suggestsuggest thatthat emeremer balsambalsam andand withwith cedarwoodcedarwood oiloil whenwhen usedused asas fillersfillers aldald inin biotitebiotite micamica schistsschists hashas formedformed inin thethe coursecourse forfor surfacingsurfacing crackscracks inin emerald.emerald. AllAll maymay bebe damdam ofof low-gradelow-grade regionalregional metamorphosis.metamorphosis. [A[A paperpaper agedaged inin cleaningcleaning byby ultra-soundultra-sound oror steam,steam, oror byby moremore interestininterestingg ttoo petrologistspetrologists thanthan toto thethe averageaverage heatingheating inin repairepairr ofof a mount,mount, butbut OpticonOpticon isis lessless gemmologist.]gemmologist.] RK.M.R.K.M. proneprone toto damagedamage inin cleaning.cleaning. TheThe epoxyepoxy resinresin isis KIRKLEY,KlRKLEY, M.B.,M.B., GURNEY,GURNEY, J.J.,J.J., LEVINSON,LEVINSON, A.A.,A.A., appliedapplied byby soakingsoaking thethe emeraldemerald inin hothot filler followedfollowed 1991.1991. Age,Age, origin,origin, andand emplacementemplacement ofof byby a surfacesurface coatingcoating ofof hardenerhardener whichwhich isis removedremoved diamonds:diamonds: scientificscientific advancesadvances inin thethe lastlast afterafter tenten minutes.minutes. TheThe filling isis hardenedhardened atat thethe decade.decade. Gems & Gemology, 27,27, 1,1, 2-25,2-25, 2020 surfacesurface butbut remainsremains liquidliquid withinwithin thethe filled crack.crack. figs. GIAGIA advocateadvocate thethe useuse ofof thethe wordingwording 'Foreign'Foreign A detaileddetailed accountaccount ofof basicbasic knowledgeknowledge ofof mattermatter isis presentpresent inin somesome fracturesfractures reachingreaching thethe diamonddiamond formationformation arrivedarrived atat inin thethe 1980s1980s surface~surface', ratherrather thanthan 'oiling''oiling'whic whichh doesdoes notnot applyapply toto whichwhich estimatesestimates thethe probableprobable ageage rangerange asas allall treatedtreated stones.stones. FilledFilled surfacesurface flawsflaws cancan bebe betweenbetween 990990 andand 32003200 millionmillion yearsyears (My)(My) basedbased expectedexpected inin stonesstones otherother thanthan emeraldsemeralds andand colourcolour isis onon age-datingage-dating ofof inclusionsinclusions ofof garnet,garnet, pyroxenes,pyroxenes, sometimessometimes addedadded withwith thethe filler. OtherOther substancessubstances etc.,etc., byby assessmentassessment ofof radio-activeradio-active residues.residues. areare alsoalso beingbeing usedused asas fillers. fillers. R . K.K. M.M. TheseThese findingsfindings havehave addedadded a greatgreat dealdeal toto thethe understandingunderstanding ofof diamonddiamond originorigin deepdeep inin thethe KANE,KANE, RE.,R.E., MCCLURE,MCCLURE, S.F.,S.F., KAMMERLING,KAMMERLING, RC.,R.C., earth'searth's mantlemantle andand itit isis nownow consideredconsidered likelylikely KHOA,KHOA, N.D.,N.D., MARA,MARA, c.,C, REPETTO,REPETTO, S.,S., KHAI,KHAI, thatthat theythey areare xenolithic,xenolithic, havinghaving formedformed inin N.D.N.D.,, KorVULA,KOIVULA, J.I.,J.I., 1991.1991. RubieRubiess andand fancyfancy eclogiteeclogite underunder enormousenormous pressurepressure beforebefore beingbeing sapphiressapphires fromfrom Vietnam.Vietnam. Gems & Gemology, 27,27 , carriedcarried somesome 150km150km toto thethe surface,surface, inin upsurgesupsurges 3,3,136-55 136-55,32, 32 figs. ofof kimberlitekimberlite oror lamproite,lamproite, fromfrom a moltenmolten zonezone AnAn importantimportant paperpaper onon newnew sourcessources ofof rubyruby andand inin thethe mantle.mantle. ItIt isis alsoalso thoughtthought thatthat ththee carboncarbon pinkpink sapphiresapphire fromfrom thethe LucLuc YenYen andand QuyQuy ChauChau areaarea sourcesource ofof diamonddiamond isis eithereither COC02 oror methane,methane, inin NorthernNorthern Vietnam.Vietnam. OtherOther localitieslocalities inin thethe southsouth ratherrather thanthan coalcoal [or[or oil?].oil?]. ProcessesProcesses involvedinvolved areare areare notnot yetyet workedworked commercially.commercially. AquamarineAquamarine andand extremelyextremely complexcomplex andand stillstill appearappear toto bebe farfar colourlesscolourless topaztopaz havehave beebeenn foundfound nearnear QuyQuy Chau.Chau. fromfrom completelycompletely understoodunderstood despitedespite thesethese MiningMining isis principallyprincipally byby open-pit,open-pit, withwith muchmuch advances.advances. AnAn interestininterestingg thoughthough complexcomplex subjectsubject contrabandingcontrabanding byby 'independent''independent' miners,miners, mostmost cryscrys wellwell treatedtreated here.here. R.K.M.R.K.M. talstals small.small. GemmologicalGemmological constantsconstants asas expectedexpected forfor corundum;corundum; twintwin laminations;laminations; inclusionsinclusions largelylargely KLEYENSTUBER,KLEYENSTUBER, A.,A., 1991.1991. ObservationObservation ofof reminiscentreminiscent ofof BurmeseBurmese oror ThaiThai rubiesrubies plusplus somesome inclusionsinclusions inin a MadagascarMadagascar emeraldemerald andand theirtheir uniqueunique toto thisthis locality.locality. StonesStones notnot heatedheated atat minemine possiblepossible implications.implications. South AfricanAfrican butbut maymay bebe treatedtreated later.later. Gemmologist, S,5, 2,2, 4-9,4-9, 6 figs (4(4 inin colour).colour). DarkDark blueblue colourcolour zoneszones commoncommon inin thethe rubiesrubies AnAn emeraldemerald fromfrom MadagascarMadagascar weighingweighing 32.5032.50 andand colourcolour isis generallygenerally patchy,patchy, swirledswirled andand treacly,treacly, ctct andand cutcut asas anan ovaloval cabochoncabochon containedcontained blackblack bluishbluish clouds,clouds, andand whitishwhitish onesones ofof largerlarger particlesparticles micmicaa flakesflakes andand fracturefracture fillingsfillings ofof yellowyellow alsoalso common,common, andand ironiron stainedstained fracturesfractures excepexcep goethitegoethite asas wellwell asas elongatedelongated hollowhollow growthgrowth tionallytionally so.so. AcicularAcicular needlesneedles thoughtthought toto bebe channels,channels, apparentlyapparently devoiddevoid ofof mineralmineral oror liquidliquid boehmite;boehmite; crystalscrystals ofof includeincludedd apatiteapatite andand calcitecalcite fillingfilling andand a largelarge individualindividual hexagonalhexagonal crystalcrystal werewere identifiedidentified whilewhile opaqueopaque rodsrods provedproved toto bebe withwith distinctdistinct yellowyellow toto greengreen pleochroism.pleochroism. ThisThis pyrrhotitepyrrhotite andand notnot rutile.rutile. LessLess oftenoften stonesstones concon isis tentativelytentatively identifiedidentified asas apatiteapatite oror tourmaline.tourmaline. tainedtained orangeorange crystalcrystal patchespatches ofof thethe rarerare mineralmineral M.O'D.M.O'D. J.J. Gemm.,Gemm., 1992,1992, 23,23, 2 111111

KOIVULA,KOIVULA, J.I.,J.I., KAMMERLING,KAMMERLING, R.C.,R.C., 1991.1991. from BurmaBurma withwith lowlow birefringence.birefringence. GemologicalGemological examinationexamination ofof a redred taaffeite.taaffeite. TanzaniteTanzanite mineminess areare beingbeing workedworked underunder ZeitschrijtZeitschrift der Deutschen GemmologischenGemmologischen TanzanianTanzanian ArmyArmy supervisionsupervision toto stopstop illegalillegal Gesellschajt,40,Gesellschaft, 40 , 1,33-7,1, 33-7 , 11 fig., flg. ,bib!. bibl . diggers,diggers, plentyplenty ofof thesethese stonesstones seenseen atat Tucson;Tucson; TheThe stonestone isis a well-proportionedwell-proportioned ovaloval ParaibaParaiba blueblue tourmalinetourmaline againagain muchmuch inin evidence;evidence; modifiedmodified brilliant-cutbrilliant-cut ofof intense,intense, medium-dark,medium-dark, furtherfurther VietnaVietnamm finds ofof rubyruby areare reportedreported fromfrom slightlyslightly brownish-redbrownish-red colour.colour. ThThee weightweight waswas LucLuc YeYenn nearnear Hanoi,Hanoi, andand sapphiressapphires fromfrom thethe confirmedconfirmed asas 0.580.58 ct.ct. MeasurementsMeasurements 5.215.21 x 4.434.43 south.south. x 3.513.51 mm.mm. SaidSaid toto bebe thethe largestlargest andand onlyonly secondsecond reportedreported redred taaffeite.taaffeite. PropertiesProperties werewere Enhancements identicalidentical toto thosethose reportedreported inin literatureliterature forfor thethe PlasticisedPlasticised AlbertaAlberta ammoniteammonite shell,shell, andand dyeddyed onlyonly otherother knownknown taaffeitetaaffeite ofof thisthis colour.colour. E.S.E.S. andand plasticplastic coatedcoated PauaPaua shellshell areare reported;reported; colouredcoloured OpticonOpticon isis beingbeing usedused toto fill emeraldemerald KOIVULA,KOIVULA, J.I.,J.I., KAMMERLING,KAMMERLING, R.C.,R.C., 1991.1991. GemGem cracks;cracks; SriSri LankanLankan rubiesrubies heatedheated byby blow-pipe;blow-pipe; news.news. Gem & Gemology, 27,1,46-55,1927, 1, 46-55, 19 figs. diffusiondiffusion treatedtreated sapphiressapphires fromfrom BangkokBangkok werewere A generalgeneral reportreport onon thisthis year'syear's TucsonTucson Show:Show: plentifulplentiful butbut similarlysimilarly treatetreatedd rubiesrubies areare notnot successfulsuccessful duedue ttoo blueblue chromophoreschromophores inin thethe Diamonds materia!'material. ColouredColoured diamondsdiamonds increaseincrease inin numbernumber eacheach year,year, mostlymostly treated,treated, commonlycommonly toto blue,blue, yellowyellow Synthetics and SimulantsSimulants andand toto brownsbrowns witwithh greygrey oror greengreen overtones;overtones; A lightlight colouredcoloured syntheticsynthetic alexandritealexandrite fromfrom naturalnatural colourscolours areare declareddeclared asas such;such; irradiatedirradiated lO.J.O. CrystalsCrystals exploitsexploits thethe pleochroismpleochroism asas wellwell asas stonesstones areare notnot - [a[a reversalreversal ofof thethe requiredrequired thethe colourcolour change,change, bubblesbubbles andand zoningzoning werewere practice!]practice!] threethree RussianRussian syntheticsynthetic yellowyellow seen;seen; Chatham'Chatham hadhad somesome 'cleaner''cleaner' syntheticsynthetic diamondsdiamonds hadhad nono colourcolour zoning.zoning. emeralds,emeralds, andand somesome extremelyextremely largelarge crystalscrystals ofof flux-grownflux-grown rubyruby withwith cleanclean areas,areas, theythey havehave nono Coloured stonesstones plansplans toto marketmarket padparadschahpadparadschah syntheticsynthetic Blue-greenBlue-green apatitesapatites fromfrom MadagascarMadagascar werewere corundum;corundum; PoolPool emeraldsemeralds areare nownow offeredoffered asas therethere againagain butbut heatheat sensitivitysensitivity makesmakes facetingfaceting KimberleyKimberley CreatedCreated Emeralds;Emeralds; lessless densedense siliconsilicon difficult;difficult; beadbead materialsmaterials includedincluded a bandedbanded (2.33)(2.33) isis beingbeing usedused toto replacereplace heavyheavy hematitehematite dolomite,dolomite, fluoritefluorite andand brecciatedbrecciated pyrite;pyrite; a cat'scat's- (5.20)(5.20) forfor beadbead materialmaterial althoughalthough lessless blacblackk inin eyeeye beryllonite,beryllonite, lookinglooking likelike ulexite,ulexite, waswas rarerare colour;colour; a naturalnatural lookinglooking imitationimitation lapislapis lazulilazuli enoughenough toto purchasepurchase forfor thethe GIAGIA permanentpermanent waswas translucenttranslucent toto intenseintense lightlight andand weaklyweakly collection;collection; a 2.892.89 ctct clinohumiteclinohumite waswas thethe largestlargest fluorescentfluorescent toto SUV,SUV, inerinertt toto L W , plastiplasticc binderbinder soso farfar seen;seen; sapphiressapphires werewere availableavailable inin suspected;suspected; gold-quartz/whitegold-quartz/white ceramicceramic doubletsdoublets profusion,profusion, mostlymostly heat-treatedheat-treated Montana;Montana; alsoalso werewere seen;seen; SovietSoviet syntheticssynthetics includedincluded thethe fluxflux- somesome BrazilianBrazilian sapphires,sapphires, againagain somesome withwith growngrown purple/purple/ redred spinels,spinels, flux-grownflux-grown colourcolour change;change; andand somesome so-calledso-called alexandrite;alexandrite; hydrothermalhydrothermal berylberyl inin a rangerange ofof padparadschaspadparadschas from UmbaUmba regionregion ofof Tanzania.Tanzania. colours;colours; syntheticsynthetic emeraldemerald onon tumbledtumbled ThaisThais areare fashioningfashioning cubiccubic zirconiazirconia andand otherother aquamarineaquamarine seeds;seeds; muchmuch syntheticsynthetic quartz,quartz, stonesstones inin squaresquare andand rectangularrectangular brilliantbrilliant stylesstyles advertisedadvertised asas SiberianSiberian BlueBlue Quartz;Quartz; syntheticsynthetic veryvery effectively;effectively; drusydrusy agate,agate, blackblack andand palepale tanzanitetanzanite andand tourmalinetourmaline areare hintedhinted atat butbut thethe purplepurple quartz,quartz, pyrite-richpyrite-rich lapislapis lazulilazuli andand otherother RussianRussian wordword forfor syntheticsynthetic isis thethe samesame asas forfor gemsgems werewere shownshown inin carvedcarved forms;forms; somesome smallsmall imitation,imitation, soso thesethese areare probablyprobably imitations,imitations, a UralianUralian berylberyl andand lighlightt emeraldsemeralds werewere examined;examined; similarsimilar mistakemistake occurredoccurred whenwhen theythey claimclaim largelarge AltaAlta Ligonha,Ligonha, Mozambique,Mozambique, isis producingproducing palepale facetedfaceted CZCZ gemsgems toto bebe 'synthetic''synthetic' diamonds.diamonds. morganite;morganite; whitewhite opalopal fromfrom PiauiPiaui StateState andand R.K.M.R.K.M. blacksblacks fromfrom BoiBoi Morto,Morto, Brazil,Brazil, werewere alsoalso seen,seen, somesome tootoo porousporous toto taketake a goodgood polishpolish andand somesome KOIVULA,KOIVULA, ll.,J.I., KAMMERLING,KAMMERLING, R.c.,R.C., 1991.1991. GemGem layeredlayered inin a spectralspectral sequencesequence ofof colours.colours. News.News. GemsGems& & Gemology, 27,27 ,2,116-25,19 2,116-25,19 figs.figs. CulturedCultured pearlspearls fromfrom TahitiTahiti werewere thethe bestbest yet,yet, withwith manymany finefine strandsstrands ofof largelarge blacks;blacks; smallsmall Diamonds peridotperidot fromfrom ArizonaArizona werewere plentifulplentiful andand a ReportsReports onon thethe 273ct273ct heart-shapedheart-shaped CentenaryCentenary 131.131.8 899 ctct oneone fromfrom BurmaBurma waswas alsoalso seen,seen, asas Diamond,Diamond, reportedlyreportedly flawless andand thethe largestlargest outout werewere bi-colourbi-colour amethyst/rock-crystal;amethyst/rock-crystal; cat'seyecat'seye sideside thethe BritishBritish CrownCrown Jewels,Jewels, butbut withwith a confusingconfusing roserose quartz;quartz; facetedfaceted rhodoliterhodolite garnetgarnet fromfrom illustration;illustration; onon a 'chameleon''chameleon' greenish-greygreenish-grey didi Orissa,Orissa, India,India, andand a violetviolet scapolitescapolite cat's-eyecat's-eye amondamond whichwhich turnedturned brownishbrownish yelloyelloww whenwhen hot;hot; onon 112 J. Gemm., 1992, 23, 2

Soviet diamond production; on Australian permit and can preform girdling in less than a minute. to explore Timor Sea for diamonds; a world record R.K.M. price at Sotheby's, Geneva, for a 101.84ct diamond (US$12,760,000); on a pair of'Star of David' shaped KOIVULA, J.I., KAMMERLING, R.C., 1991. Gem double twinned macles; a bluish-grey boron-rich News. Gems& Gemology, 27, 3,180-90,16 figs. micro-coating of low-temperature synthetic di amond on colourless diamonds had high electrical Diamonds conductivity, and could also be detected by an edge Argyle are expanding ore processing at AKI pipe, fugitive tendency giving a white abraded look under WA, to keep up with lesser productivity at depth, magnification. and are now cutting diamonds in China; Namibia's Elizabeth Bay deposit has been reopened as an Coloured stones open-cast mine by Consolidated Diamond Mines Reports on tourmalines from Namibia, Zambia and expects to produce about 2.5 million carats of and Madagascar; on increased ruby output from mainly gem quality stones in the next ten years; Tanzania, with better padparadscha from the Umba there is much organized theft there particularly River region, and on aquamarine from Zimbabwe, from the Orangemund mine; a major new Russian amethyst from Afghanistan; ruby in green mica diamond field is reported at Baryatskaya near the from Northwest Frontier Province, Pakistan; a Mongolian border. joint venture to cut and market Uralian emeralds; The second European Conference on diamond, labradorite from Madagascar carved as cubes, diamond-like and allied coatings held in Nice was spheres and other shapes; opal with fine greenish notable for the number of presentations on di body colour from Peru; iridescent green exo- amond-like coatings (extremely hard amorphous skeletons of beetles mounted as jewellery. The first carbon of great potential in industry, an inherent auction of Cook Island black cultured pearls had colour seems to be a problem with DLC, but the many silver grey pearls and sold just over half the brown of CDV (carbon vapour deposition) films is items offered, mostly to Japan; rich green transpa due to interstitial graphitic deposits and may be rent zoisite is available from the Merelani district of improveable. Tanzania, and resembles the fine tourmalines of Maico Diamonds recently introduced their Paraiba, Brazil. 'Dream-cut' diamonds which have the normal rounded girdle left straight-sided, making the table Enhancements look larger and utilizing relatively flatter rough. Buffing settings of aqua aura blued stones can Small modifications of facets help to minimize light remove the gold coating and spoil the colour; jadeite leakage normal to shallow stones, with resultant with cracks filled with epoxy resin is reported; greater weight yield and larger looking stones. quartzite beads dyed to lavender blue were offered [Brilliant, marquise and drop are illustrated but as dyed jadeite, penetration of colour was complete; images are too confused to allow one to assess gems made from fibre optic glass are described and details]. GIA report finding stereoscopic photo illustrated; backed Mexican opal slices embedded graphs taken at the turn of the Century relating to in plastic to simulate black opal are offered as 'opal early diamond mining in S. Africa. encapsulado'; plastic imitations of opal containing iridescent films or foil were purchased in Bangkok, Coloured stones multitudinous gas bubbles made the deception Colombian emerald exports reached an all time obvious; Russian flux-synthetic red spinels seen in high in 1990, mostly to Japan. A large grey South recent years have been made from 'defective' natural Sea pearl is reported in Thailand, 42mm long with crystals from the Pamir Mountains so constants high lustre, when shaken internal liquid could be approach those of natural spinel. heard; Myanmar is to permit export of rough and cut stones to a Thai company in Rangoon; a Instrumentation Myanmar postage stamp illustrates the 496.5ct A dark-field loupe has been developed by GIA Nawata ruby rough found at Mogok in 1990 and GEM; two new automated and versatile cutting confiscated the same year as illegally mined; much machines have been developed to facet girdle edges Thai sapphire is still produced by traditional hand of diamonds, one in Belgium, the other in Israel; an mining and sorting. Attractive pink spinels from Israeli firm offers ROBOGEM, a computerized Umba River region of Tanzania were seen at the stone cutting machine which has image-processing Tucson show, some were velvety with sub- technology to provide 'optimum yield' from rough microscopic inclusions; the Longido ruby mine, and can be programmed to produce all common Tanzania, is being worked again producing shapes, graduated sets, pairs or maximum weight, cabochon grade stones; the Tanzanian government J. Gemm., 1992, 23, 2 113

invites tenders for mineral rights in the Merelani Lava Fields in the north. Sapphire tends to occur in tanzanite area. basaltic rocks which are widespread in these areas. Large Paraiba blue/green tourmalines are now R.K.M: reported; two African tourmalines were colour- change when seen in combined incandescent and KROSCH, N.J., COOPER, W., 1991. Queensland fluorescent light, and fluoresced chalky yellow Sapphire: part II. Australian Gemmologist, 17,12, under SUV; dissimilarity of pleochroism between 511-15. brown tourmaline and andalusite is noted and a Deals with surface, shaft and large scale mecha warning given on over-reliance on visual clues to nical mining, producers, production, marketing identify; idocrase in purple, green and bi-colour and future potential. Most stones are cut in Thai have been found at Jeff er y mine in Quebec; an land. Competition from Nigeria and China antici unusual black tanzanite was pleochroic in red, pated. R.K.M. greenish and purple along its principal axes under powerful light [would heat have made this a usable LINTON, T., BROWN, G., 1991. Polaroid stone?]. 'spectra' system with close-up stand Model 7500. Australian Gemmologist, 17, 10, 429-31, Enhancements 4 figs. There are reports of diamond-film coated stones Report on a Polaroid camera adapted for but GIA are aware of only three diamonds which close-up photography of gems and small were experimentally coated with Type lib blue jewellery says shallow depth of field (<12mm) diamond film; DLC films adhere to a variety of soft plus high cost of camera and film makes it less stones and sapphire point will not scratch them, attractive than claimed, while centre definition they impart anomalous adamantine lustre and a leaves something to be desired. R.K.M. brownish tint to the stone [Do such ultra-thin coatings affect the RI?]. Dry Cottonwood Creek LINTON, T., BROWN, G., 1991. Coral identification mine, Montana, is producing blue and yellow kit. Australian Gemmologist, 17, 11, 465. sapphires which can be heated to deepen the colour, A collection of 15 different corals, both rough and some develop unwanted zoning; experimental polished, from deep waters south of Tasmania, diffusion of red colour into corundum has so far including various bamboo corals, black and gold been unsuccessful and some stones lose colour from corals, with notes on the main features which over-polishing. identify corals from these seas. Reasonably priced at $A25. R.K.M. Synthetics and simulants A white Gilson type synthetic opal adhered to the LINTON, T., BROWN, G., 1991. The Shibuya 150 tongue and absorbed water readily. gemmological refractometer. Australian Gemmo logist, 17, 11,468-9, 2 figs. Instrumentation and new techniques A Japanese refractometer with scale range from It is pointed out that heat-coating and heat- 1.30 to 1.83, but supplied in this case with 1- diffusion are different processes, the former does bromonaphthalene (RI 1.66) as contact fluid. An not affect pleochroism, while this is enhanced by in-built yellow interference filter is not quite as heat diffusion of colour. A new method of setting accurate as a sodium light source, but the instru diamonds in a carbon-based polymer plastic defeats ment is assessed as high quality. Some difficulties thermal conductivity tests but inclusions are still were experienced with spot testing high RI typical of diamond and the X-ray transparency test cabochons. still applies; a new and greatly improved colour imaging process is described and so is surgical tape LINTON, T., POLITA, M., BROWN, G., 1991. A to increase the adhesion of gem tweezers. R.K.M. new dark-field loupe. Australian Gemmologist, 17, 10, 396-7, 2 figs. KROSCH, N.J., COOPER, W., 1991. Queensland A report on an American lOx dark-field lens Sapphire. Australian Gemmologist, 17,11,460-4,2 combined with a focusing Mini-Mag pocket maps. torch. Efficient when batteries are new but The first instalment of a paper based on a restricted for large sizes of stone, and expensive. Queensland Govt. Mining Journal report of 1990 R.K.M. dealing with the many sapphire areas of eastern Queensland, only two of which are mined on a MCCABE, A. J., 1991. Paua shell and how to work it. commercial scale. These are the Rubyvale, Sap Wahroongai News, 25, 7, 4-7. phire and Anakie region in central Queensland and Advice on working rough paua shell to a satisfac- 114 J. Gemm., 1992, 23, 2

tory finish. The rather strange Maori name IS gravel are washed and sieved daily to yield about pronounced 'pa-wa: R.KM. 45kg of concentrates, which are then hand-sorted to give about 5kg of cuttable crystals yielding rose NIEDERMAYR, G., 1991. Eine Dose aus curs from 3 to 5mm in diameter. Weight loss in Bleiberger Muschelmarrnor. Mineralien Welt, cuttingis said to be only 10%. RKM. 2, 4, 49-52, 6 figs (5 in colour). Examples of fire marble from the Natural SCHMETZER, K, 1991. Lechleitner synthetic emer History Museum in Vienna are illustrated with alds, rubies and sapphires. Australian Gemmolog notes on their composition and on the places ist, 17, 12,516-23,18 figs. where the material was found. Chief among Deals in some detail with each type of synthetic these is Bleiberg, Carinthia, Austria. M.O'D. produced by Johann Lechleitner, who is now 70, from A to F; type B, natural seed beryl, over-grown PAULITSCH, P., 1991. Kupfer und Jade aus with thin plates of chrome-rich synthetic emerald; China. Aufschluss, 42, 207-12, 2 photos in type D, fully synthetic emerald grown on a central colour, 1 fig. synthetic seed, and type F, flux-grown full synthetic The history and use of jade in China is briefly emerald are available commercially. Lechleitner described with notes and tables of jade-like started experimenting with synthetic corundum in minerals. Copper also features in the paper. 1983 again by over-growth of synthetic ruby on M.O'D. colourless Verneiul cores, and other colours fol lowed, using molybdenum and lead fluxes; follow REDMANN, M., HENN, U., BANK, H., 1991. ing year he produced ruby by coating synthetic SchleifwUrdiger, klar durchsichtiger, ruby onto natural corundum cores. All these are farbloser bis blassgelblicher Thaumasit aus, composite or synthetic stones and must be so Sudafrika, (Cuttable, transparent, colourless marketed. R.KM. to pale yellow thaumasite from South Africa.) Zeitschrift der Deutschen Gemmologischen SCHMETZER, K., BERHARDT, H-J. BIEHLER, R, Gesellschaft,40, 1,67-8, bib!. 1991. Emeralds from the Ural Mountains, USSR The colourless to pale yellow gem quality Gems& Gemology, 2~, 2, 86-99,14 figs. thaumasite from the Black Rock mine in the Emeralds from the Takovaya River area, north of Kalahari manganese field is described. No = Sverdlovsk, in eastern Urals, are being found in 1.505-1.510, n e = 1.467-1.480, DR 0.030 quantity, as a by-product of beryllium mining, after 0.038, SG 1.88-1.91. E.S. a lapse of several decades. Qualities vary from pale to dark green and from heavily included to flawless. ROBERT, D., 1991. Un simulant de roches Rls vary from 1.581p1.575 to 1.590-1.582, SG from mauves. Revue de Gemmologie, 107, 3-6, 3 figs 2.72 to 2.75. Three-phase inclusions are less fre in colour. quent than in Colombian stones and lack the jagged Charoite, sugilite and common beryl are outline of the latter; healed fractures, flat liquid reviewed as mauve gem or ornamental materials. filled feathers parallel to the basal pinacoid, and M.O'D. phlogopite and other inclusions are common but most are similar to inclusions from other localities. RUFU, J.-C., 1991. Ny intensiv bla och gran RKM. Adelsten fran Brasilien! Gem Bulletinen, 1/91, 2 3. A brief note on the deep blue tourmalines SCHWARZ, D., 1991. Die chernis chen recently found in Paraiba, Brazi!. Adapted from Eidenschaften der Smaragde. II Australien a paper in Gem News. M.O'D. und Norwegen. (The chemical properties of emeralds. II Australian and Norwegian.) SCHLUTER, J., WEITSCHAT, W., 1991. Bohemian Zeitschrift der Deutschen Gemmologischen garnet - today. Gems & Gemology, 27, 3, 168-73, Gesellschaft, 40, 1, 39-66, 1 photomicrograph, 16 figs. 2 maps, 6 graphs, 5 tables, bib!. Pyrope has been mined commercially in what is The emeralds from Norway came from now Czechoslovakia since the 16th century and Eidsvoll near the Mjosa Lake, the Australian although now considered exhausted a small mine specimens from Pilgangoora, Wodgina, Calvert still operates at Podsedice in the Bohemian Hills. White Quartz Hill, Warda Warra, Melville and Stones are cut and set in Turnov. The alluvial Torrington in Western Australia, Emmaville in deposit is from peridotite pipes and the garnet is New South Wales and from Menzies in West mostly in small crystals. Other localities are being Australia. On average, compared with the explored. Mining is open-cast and 320 tonnes of Brazilian material, there is less magnesium, J. Gemm., 1992, 23, 2 115

sodium and iron content in both the Norwegian URMOS, J., SHARMA, S.K., MACKENZIE, F.T., and Australian stones, especially the Norwegian 1991. Characterization of some biogenic and the Emmaville samples have extremely low carbonates with Raman spectroscopy. Na20 and MgO contents. The Mjosa emeralds American Mineralogist, 76, 641-6, 3 figs. have a high vanadium content. E.S. Biogenic carbonates from a scleratinian coral (Porites sp.), Corallium reale and C. secundum SCHWARZ, D., 1991. Australian emeralds. Austra corals, pink and uncoloured respectively and lian Gemmologist, 17,12,488-97,3 figs and a map. from natural and cultured pearls are examined Part of a research on emeralds from main sources by Raman spectroscopy. Aragonitic Porites coral world-wide by microprobe, more of interest to the and pearls show Raman bands characteristic of petrologist or mineralogist than to the gemmologist. aragonite but bands from the natural pearl are R.K.M. slightly sharper than the corresponding bands from Porites and cultured pearls. Deep-sea SHERRIFF, B.L., GRUNDY, H.D., HARTMAN, precious corals show Raman spectra closely J.S., HAWTHORNE, F.C., CERNY, P., 1991. resembling those of magnesian calcite but pink The incorporation of alkalis in beryl: multi- corals show seven additional bands in the region nuclear MAS NMR and crystal-structure 1020-3759cnr1. The extra bands are attributed study. Canadian Mineralogist, 29, 271-85, 10 to a carotenoid pigment which gives rise to the figs. pink colour of the coral skeleton. M.O'D. Stereochemical details of the incorporation of alkali ions into the beryl structure are examined VON BEZING, K.L., DIXON, R.D., POHL, D., using multi-nuclear MAS NMR spectroscopy CAVALLO, G., 1991. The Kalahari manganese and single-crystal structure refinement. M.O'D. field: an update. Mineralogical Record, 22, 279-97, 38 photos (18 in colour), 1 map. STÖTZEL, N., SCHWEISFURTH, G., Gem quality crystals of rhodochrosite and HOCHLEITNER, R., 1991. Siegerland- sugilite are among the minerals listed and Mineralienland. Die klassischen described in this update. The crystals are small Mineralstufen aus den Siegerländer in general. A complete list of minerals Erzgangen. Lapis, 16, 7/8, 27-67, 115 photos discovered so far and a list of references are (95 in colour), 6 figs. given. M.O'D. Fine quality rhodochrosite, malachite and sphalerite are among the minerals found in the German Siegerland mining area. Other minerals WELZEL, J., 1991. Glass Art - now and then, are described and illustrated and a complete list Industrial Diamond Review, 51, 141-3, 5 figs for the area is given. M.O'D. (2 in colour), bibl. In reproducing famous glassware from the TILLANDER, H., 1991. En kritisk Analys av De classical period and finishing it by fine grinding Beers Diamantbroschyr. Gem Bulletinen, 1/91, and engraving, master craftsman J. Welzel is 10-16. convinced that diamond abrasives were in use Review of a pamphlet on diamond grading from the first to the fourth century AD. issued by De Beers for consideration within the Mr Welzel has reproduced the Lykurgos Scandinavian countries in 1989. M.O'D. goblet and the Portland vase. E.S.

TOMBS, G., 1991. Some comparisons between Ke ZEIHEN L.G., 1987. The sapphire deposits of nyan, Australian and Sri Lankan sapphires. Montana. Bulletin, Montana Bureau of Mines Australian Gemmologist, 17,11,446-9, 6 figs. and Geology, No. 126, 28-39, 5 photos, 2 maps. Corroded, fragmentary crystals of sapphire from The three main sapphire-bearing areas Kenyan sources at Garba Tula, Lodwar and Sam- described are the Yogo Creek deposits and those buru are compared with Australian (New England) on the Missouri River bars and on Rock Creek. and with Sri Lankan sapphires, and the differences A brief mention is made of other deposits. In in colour enhancement by heating attributed to the general sapphire crystals are small with a wide considerable variations in iron content. Repairers range of colours. Few finished stones would are warned to unset sapphires before applying heat reach two or more carats but the colours can be to a mount. R.K.M. very fine in many specimens. M.O'D. 116 J. Gemm, 1992,23,2

Proceedings of The Gemmological Association and Gem Testing Laboratory of Great Britain and Notices

OBITUARY and Amanda Goode gave illustrated lectures to an Mr R.L. Austen, FGA (D.1937 with Dist.), audience of more than 150 on the gemstone Chichester, died on 9 December 1991. deposits and trade in Sri Lanka. Mr Edwin T. Mills, FGA (D. 1986), Ely, died on 10 February 1992. Midlands Branch Professor Dr D.H.G. Keuskamp, FGA On 17 January 1992 at Dr Johnson House, Bull (D.1981), Streefkerk, Netherlands, died on 12 Street, Birmingham, a members' practical evening February 1992. was held. Mr R.W. Yeo, FGA (D.1929 with Dist.), On 21 February 1992 at Dr Johnson House, Mr Instow, died in February 1992. A full obituary will Clive Burch gave an illustrated lecture on inclu be published in a future issue of The Journal. sions in gemstones. On 20 March 1992 at Dr Johnson House, Mr NEWS OF FELLOWS David Callaghan gave an illustrated lecture on Mr Alan Hodgkinson, FGA, represented the cameos and intaglios entitled 'On the face of it'. Gemmological Association and Gem Testing Laboratory of Great Britain by giving two lectures North West Branch at the Tucson Gem & Mineral Fair in February On 15 January 1992 at Church House, Hanover 1992. Street, Liverpool 1, Mr David Pelham gave an Following on from last year's theme, this year's illustrated lecture entitled 'Small scale gold min heading was 'A further taste of Scottish gemmol- ing and gem mining'. ogy', but behind the lighthearted title was a wealth On 19 February 1992 at Church House, Helen of factual information on gem testing techniques Fraquet gave a lecture on 'Amber'. and the latest finds and developments of natural On 18 March 1992 at Church House, Dr Jeff and artificial gemstones. Harris gave an illustrated lecture entitled 'An The diamond/graphite coating on a brilliant-cut aspect on diamonds - alluvial diamond deposits'. cubic zirconia caused such interest that it was dis played on the stand of the Canadian Gemological Association and American Gemological MEETINGS OF THE COUNCIL OF Association via close circuit television from a MANAGEMENT microscope video. The two 'one-and-a-half hour' At a meeting of the Council of Management lectures lasted five hours in all, and with a stand held on 18 December 1991 at Chapel House, ing room only situation the door had to be shut to Hatton Place, London EC IN 8RX, the business prevent further entry. transacted included the election to membership of On 3 April 1992 Dr J.B. Nelson gave an illus the following: trated talk on 'Gemmological teaching in Hong Kong and China' to the Sussex Mineral and Fellowship Lapidary Society at Haywards Heath. Anastassiou, Evagelia, Athens, Greece. D. 1991. Chan, Nga Y., Causeway Bay, Hong Kong. D. MEMBERS' MEETING 1991. London Chu, Yiu W.T., Kowloon, Hong Kong. D. On 10 March 1992 at the City Conference 1991. Centre, Mark Lane, London EC3, Alan Jobbins Chudawala, Sucheta, Bombay, India. D. 1991. J. Gemrn., 1992, 23, 2 117

FORTHCOMING EVENTS

London

Meetings will be held at the City Conference Centre, 76 Mark Lane, London EC3R 7JN, at a cost per lecture of £5.00 for GAGTL members, £10.00 a member and a guest, and £8.00 for non- members. Further details and tickets from the GAGTL.

Gemstone deposits and the trade associated with them

Tuesday 9 June 1992 South East Asia Tuesday 24 November 1992 Africa

North West Branch

Meetings to be held at Church House, Hanover Street, Liverpool 1. Further details from Irene Knight on 051-924 3103.

20 May 1992 Nigel Israel. 'Historical aspects and valuations' 17 June 1992 'Exchange and Mart'. Buying and selling of books, crystals and instruments, plus social evening 16 September 1992 Adrian Klein. 'Emerald' 21 October 1992 Dr Jamie Nelson. 'Optical attributes of a diamond' 18 November 1992 Annual General Meeting

TRADE WORKSHOPS IN JULY

GAGTL staff will be running their popular Trade Workshop again in July. More than a dozen people are already on the waiting list for this Workshop, and if you wish to take part in observing gem materials from the trade point of view, please contact GAGTL Education Office on 071-404 3334 for further details. The Workshop will be held close to Hatton Garden and will cost £60.00 plus VAT.

Chung, Tsz K., Kowloon, Hong Kong. D. Mourogiannis, Stephanos, Volos, Greece. D. 1991. 1991. Doshi, Setu H., Bombay, India. D. 1991. Ng, Chee K., Quarry Bay, Hong Kong. D. Ghisi, Maria, London. D. 1991. 1991. Ha, Wai M.C., Kowloon, Hong Kong. D. 1991. Oo, Thein L., Singapore. D. 1989. Harrison, Victoria A., Taunton. D. 1991. Pang, Shing C, Kowloon, Hong Kong. D. Khimji, Priti, London. D. 1991. 1991. Lai, Mui G.M., Hong Kong. D. 1991. Simmons, Charlotte R., Huntingdon, Md., Lau, Mee S.L.M., Kowloon, Hong Kong. D. USA. D. 1991. 1991. Vesters, Marco., Hertogenbosch, The Lee, King T., Kennedy Town, Hong Kong. D. Netherlands. D. 1991. 1991. Wong, Hon C., Kowloon, Hong Kong. D. 1991. Lilley, Elaine, London. D. 1991. Wong, Siu P., Kowloon, Hong Kong. D. 1991. Merchant, Azmet, Bombay, India. D. 1991. Yeung, Kit Y.K., Hong Kong. D. 1991. Zhang, Linxia, Shen Zhen, China. D. 1991. 118 J. Gemm, 1992, 23, 2

Ordinary Membership At a meeting of the Council of Management Allaman, John, Sarasota, Fla., USA. held on 19 February 1992 at Chapel House, Beckett, Shona-Maria F., London. Hatton Place, London EC IN 8RX, the business Beltran, Luruenta F J., Madrid, Spain. transacted included the election to membership of Bevoort-Alwicher, Terrence, GE Nijmegen, The the following: Netherlands. Bolton, Jane A., London. Fellowship Butler, Ian P., High Barnet. Campomanes Eguiguren, Amalia, Alicante, Campbell-Pedersen, Maggie, London. Spain. D. 1991. Chan, Lo M.Y.F.C., Kowloon, Hong Kong. Xue, Qinfang, Hubei, China. D. 1991. De Jongh, Laurentia M., The Hague, The Yang, Mingxing, Hubei, China. D. 1991. Netherlands. Zhang, Fan, Huei, China. D. 1991. Deshapriya, Sarath B.A.M., Perivale. Drowley, Brigitte, Haslemere. Ordinary Membership Frutos, Carmen, London. Arai, Takahiro, Chiba Pref, Japan. Hertani, Abdul, Lancing. Hasegawa, Tomoko, Tokyo, Japan. Huang, Chin T., Taipei, Taiwan. Higo, Kenji, Qsaka, Japan. Humphrey, Mary S., London. Higo, Yoshiko, Osaka, Japan. Kinnunen, Kari A., Espoo, Finland. Horsfall-Ertz, Priscilla J., London. Makoundoul, Chris M., Solva, Sweden. Hotta, Shigemitsu, Nara Pref, Japan. Matsumoto, Naoko, Chicago, 111., USA. Ikeda, Noriko, Hyogo Pref, Japan. Messer, J. Wayne, Candler, NC, USA. Kariya, Tomoko, Tokyo, Japan. Packard, Alice V., London. Katsuta, Morifumi, Osaka, Japan. Rochat-Huguenin, Chantai, Lausanne, Kiji, Michio, Osaka, Japan. Switzerland. Kinda, Yumiko, Osaka, Japan. Sarmento, Rodrigo W., Lisboa, Portugal. Klein, Jeffrey L., Southend on Sea. Wilkins, Anthony E., Bridgwater. Liu, Zhao, Hubei, China. Magara, Yoshiaki, Fukui Pref, Japan. Mina, Jacqueline, Twickenham. Mitsuno, Atsushi, Kyoto, Japan. At a meeting of the Council of Management Miyamoto, Kiyomi, Osaka, Japan. held on 22 January 1992 at Chapel House, Hatton Morino, Yoshio, Tokyo, Japan. Place, London EC IN 8RX, the business trans Mumetani, Miho, Hyogo Pref, Japan. acted included the election to membership of the Murakami, Chie, Osaka, Japan. following: Nakamura, Haruji, Kyoto, Japan. Nakane, Chie, Hyogo Pref, Japan. Fellowship Nishimura, Tadahiro, Osaka, Japan. Bakagianni-Sabou, Aristea, London. D. 1991. Noritomi, Hidekazu, Osaka, Japan. Baxendale, Paul D., London. D. 1965. Odawara, Hiroko, Osaka, Japan. Dietz, Susanne C, Koenigstein/TS, Germany. Park, Jung S., Seoul, Korea. D. 1990. St Clare, Edward, Southport. Mehra, Shilpa, Hong Kong. D. 1991. Sakaki, Kouki, Ibaraki Pref, Japan. Nolet, Theresa A., Castlegar, BC, Canada. D. Sano, Hajime, Tokyo, Japan. 1991. Semi, Saoko, Kanagawa Pref, Japan. Ranabahu, Mallikage K.T.S.N., Ratnapura, Sri Takai, Reiko, Niigata Pref, Japan. Lanka. D. 1982. Tanaka, Kazuhide, Osaka, Japan. Samaranayake, Ravinda, Colombo, Sri Lanka. Tanaka, Mariko, Hyogo Pref, Japan. D. 1991. Taniguchi, Toshiko, Osaka, Japan. Tateno, Haruyuki, Ibaragi Pref, Japan. Ordinary Membership Uchi, Naoko, Hyogo Pref, Japan. Boulton, Brian C, London. Udagawa, Koichi, Tokyo, Japan. Harper, Jonathan, London. Warne, William R., Birchington. Hart, Juliana L., Colonel Light Gardens, S. Yamagami, Mayumi, Tokyo, Japan. Australia. Yamasuga, Ryoji, Hyogo Pref, Japan. Leong, Weng, Maidstone. Yashima, Aiko, Hyogo Pref, Japan. Schmetzer, Karl, Peterhausen, Germany. Zhang, Yabin, Hubei, China. Speet, Scilla M.A., London. Zubaida, Albert, London. F.G.AEG.A.. I youyourr kekeyy ttoo ththee fascinatingfascinating I worlworldd ooff GemmologyGemmology I

ThThee GemmologicaGemmologicall TheThe GemmologicalGemmological AssociatioAssociationn anandd GeGemm Association'sAssociation's coursecourse TestinTestingg LaboratorLaboratoryy ooff hashas beenbeen speciallyspecially GreaGreatt BritaiBritainn hahass beebeenn compiledcompiled iintntoo aa seriesseries activelactivelyy involveinvolvedd iinn ofof teachingteaching modulesmodules the very beginning of the very beginning of thatthat areare bothboth readablereadable Gemmology as an and lavishly Gemmology as an and lavishly independent science. illustrated. independent science. illustrated. Today, the Together they Today, the Together they Association takes provide a Association takes provide a pride in its comprehensive step pride in its | comprehensive step- international by-step guide to the international by-step guide to the reputation as a learned fascinating world of reputation as a learned fascinating world of society dedicated to gemmology and an society dedicated to gemmology and an the promotion of opportunity to earn opportunity to earn thgemmoe promotiologicaln of the coveted initials gemmologicaeducation andl the FGAthe covete - Fellowd initial of thes educatiospread onf and the GemmologicalFGA - Fellow o f the spread of Gemmological gemmological The Association. gemmologicaknowledge. l AssociationTo find out. more knowledgeThe Associat. ion's Gemmological Association completeTo find outhet morcoupone The Association's Gemmological Association complete the coupon co~eted Fellowship is and Gem Testing Laboratory below and we will covetea markd ofFellowshi excellencep is and Gem Testing Laboratory immediatelybelow and w efo wilrwardl aonly mar bestowedk of excellenc upone Of Great Britain theimmediatel Associatyi onforwar's d onlindividualsy bestowe whod upo n th1992e Association' prospectuss . I Of Great Britain individualsuccessfullys wh undertakeo the Association's giving full details of 199this2 unique prospectu courses successfullwritten andy practundertakical examinationse the Association' s giving full details of this unique course writtecov.eringn an alld practicalaspects ofexamination gemmologys as a coverinscience.g all aspects of gemmology as a science. IPIeose complete andreturn iJle Gemmologkol Association Training Sd1eme~ -- , IIpJeas 27 Glee villcomplete Sheee t,an lond returdoo nE Clto Nthe8SU Gemmologica England Tell :Associatio (071 ) 404n Trainin 3334g. SchemeFax (071)404. 8843 I i I' 27 Greville Street, London EC1N 8SU England Tel: (071) 404 3334. Fax (071) 404 8843I I Nome I I ~Nameon I I I I (ompoPositionny I I I I ACompanddless y I I Address I I I Telephone 1 L ______.-1 Telephone L. .j 120 J. Gemm, 1992,23,2

At a meeting of the Council of Management Hugh Rice Ltd., 10-14 George Street, Hull, N. held on 18 March 1992 at Chapel House, Hatton Humberside HUI 3AJ. Place, London EC IN 8RX, the business trans The Jewellers & Silversmiths, 15 Thames Street, acted included the election to membership of the Kingston Upon Thames, Surrey. following: REPLICA DIAMONDS Fellowship One of the attractions at the Birmingham NEC Colborne, Janette., Brisbane, Australia. D. Jewellery and Giftware Fair in February was the 1991. public launch on the GAGTL stand of a new Van Den Haak, Hester, Krimpen, The series of cubic zirconia stones cut to imitate Netherlands. D. 1991. famous diamonds. The series also includes sets which show the most popular cuts used for dia Ordinary Membership monds, the development of the brilliant cut, and Alteen, Michael L., Nova Scotia, Canada. a range of round brilliants of different weights. Boote, Caroline M.E., London. Each of 13 famous diamonds can be bought sep Deolia, Damji, Hounslow. arately and are available through Gemmological Dillistone, Jason S., Hove. Instruments Ltd., Fax 071-404 8843. Dinnis, Simon J., Swadlincote. Duigan, Ingeborg, Kowloon, Hong Kong. GEM & MINERAL FAIRS 1992 Hug, Markus E., Schaffhausen, Switzerland. Gem and Mineral Fairs will be organized by the Page, Tayma F.L., Hong Kong. British Lapidary & Mineral Dealers' Association Roper, Bebs, Tasmania, Australia. during 1992 as follows: Yenson, Patrick, London. Leicester 16-17 May 1992. Holiday Inn. Harrogate 29-31 August 1992. Crown Hotel. MEETING OF THE TRADE LIAISON London 17-18 October 1992. Holiday Inn, COMMITTEE Swiss Cottage. At a meeting of the Trade Liaison Committee Further details from Fair Organizer: John F. held on 13 February 1992 at 100 Hatton Garden, Turner, Glenjoy, 19/21 Sun Lane, Wakefield, W. London EC1, the business transacted included Yorkshire. Telephone 0924 373786. the election to membership of the following:

Gold Laboratory Membership Johnson, Walker & Tolhurst Ltd., 64 Burlington Arcade, London W1V 9AF. Letter to the Editor CA. Rotenberg Ltd., Suite 130, 100 Hatton Garden, London EC 1. Blacklock & Son, 15 Waterloo Place, From A . E. Farn Sunderland SRI 3HT. Boodle & Dunthorne, 35 Lord Street, Liverpool, Dear Sir, Merseyside. It is unfortunate that letters to the Editor have Manny Gordon Trading Inc., 580 Fifth Ave., three months to wait before a reply dealing with Suite 610, New York, NY 10036, USA. the matter can be published. Worse still if a reply Michael Hager & Sons, Suite 110, 100 Hatton is published six months later, by which time the Garden, London EC IN 8NX. patient reader may well say, 'what are they on L. & R. Josyfon Ltd., 100 Hatton Garden, about'. Phrases such as 'Storm in a teacup' or London EC 1. 'Much ado about nothing' spring readily to mind. Teh Jun Co. Ltd., Room 1206, Lane Crawford Keith Mitchell and myself are friends of long House, 70 Queens Road Central, Hong standing, we both hold the works, researches and Kong. memory of Basil Anderson in great admiration. S. Müller & Sons NV., Schupstraat 1-7, Bus 6, Thus when I used the word, 'treatise' incorrectly 2018 Antwerp, Belgium. in describing Keith Mitchell's work in a book to C.N. Ross-Field Ltd., 12 Hatton Garden, be published by Eric Bruton it was an enthusi London EC IN 8AN. astic attempt on my part to draw attention to and hopefully to spur gemmologists to buy the Ordinary Laboratory Membership book when it appears. Thirty five years at the Pinkertons the Jewellers, 48 Market Street, laboratory, most of them in close working contact Brighton, Sussex BN 1 1HH. with Basil Anderson, all of them in friendship J. Gemm., 1992, 233 2 121

with Keith Mitchell, probably promoted 'an that the Koh-i-Noor was reçut and polished by enthusiasm too far'— mea culpa. two workers from Costers of Amsterdam who To revert to other contents of the January came to London to carry out the work at the Journal, on pp 40,41, under the sub-title 'The premises of Messrs. Garrard in Panton Street, Crown Jewels', I was particularly interested to London, in 1862. read of the Koh-i-Noor. Purely by coincidence I De Beers, 'Notable diamonds of the world', states was reading up the details of the Koh-i-Noor for that two workers from Costers of Amsterdam material for a short story, fiction based on facts, came to London to carry out the work. The result the day before the Journal arrived. Since we are was a weight of 108.93ct. Thus is my confusion informed on page 41 that in 1986 it was decided confounded by a convergence of data. to compile a detailed account of the collection by staff of the GAGTLI feel hesitant to query the fig Yours sincerely ures quoted for the Koh-i-Noor. A.E. Farn The Journal article on the Koh-i-Noor states: 18 February 1992 'The Koh-i-Noor was reçut in 1852 from Seaford, E. Sussex. 186.10ctto 105.60ct'. Eric Bruton's 'Diamonds', p4, states, 'The Koh-i-Noor was reçut in The Koh-i-Noor was removed from its setting in 1988 to ascertain exact Amsterdam to 108.93ct'. On page 452 it states weight; 105.60ct is the correct figure. Ed.

ADVERTISING IN Museums, Educational THE JOURNAL OF Establishments GEMMOLOGY & Collectors The Editors of the Journal invite I have what is probably the largest range advertisements from gemstone of genuinely rare gemstones in the UK - and mineral dealers, scientific from Apophyllite to Zincite. Also rare instrument makers, publishers synthetics, i.e. Apatite, Scheelite, and others with interests in the Bismuth Germanate, Knischka rubies gemmological, mineralogical, and a range of Inamori. lapidary and jewellery fields. Lists available NEW LIST of inexpensive stones Rates per insertion, excluding suitable for STUDENTS VAT, are as follows: (Please send three first class stamps) Whole page Half page Quarter page £180 £100 £60 A. J. FRENCH F.G.A. Enquiries to Mrs M. Burland, Advertising Manager, Gem Dealer & Consultant Gemmological Association, 82 Brookley Road 27 Greville Street, Brockenhurst, Hants S042 7RA London EC1N8SU. Telephone: 059023214 122122 J.J. Gemm.,Gemm., 1992,1992, 2323,, 2 GEMSCALGEMSCALE50E 50 TheThe PocketPocket CaratCarat ScaleScale ferfer ProfessionalProfessional Useuse

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BecauseF.ecause whethewhetherr yoyouu livlivee iinn EnglanEnglandd oO,rr ThailandThailand,, gemstonegemstoness anandd mineralmineralss araree jusjustt a ass fascinatingfas<;inating.. AnAndd nnoo otheotherr magazinmagazinee covercoverss ththee gegemm an andd jewelr jewelryy art artss liklikee LapidaryLapidary Journal. Journal. EverEveryy monthmonth,, you'lyou'lll heahearr fromfrom ththee field'field'ss totopp expertexpertss aass thetheyy reporreportt t oto yo youu ththee lates latestt discoverie discoveriess iinn mineralogymineralogy anandd gemologygemology.. LapidaryLapidary Journal Journal takes takes you you on o ngemstone gemston eexpeditions expeditions, invites, invite ysou yo intou int o studiostudioss o off note notedd artisans artisans,, anandd thethenn setsetss .,uupp shoshopp iinn youyourr owownn homhomee toto teacteachh yoyouu ththee mosmostt basibasicc ttoo ththee mosmostt revolutionarrevolutionaryy cuttincuttingg anandd jewelrjewelryy makin makingg techniques techniquRs.. What'What'ss moremarc,, onl0 ],11yy LapidaryLapida ry JournalJournal intro- intro duceducess yo youu t oto ove overr 45 4500 supplier supplierss an aridd service servicess thathatt yoyouu cacann bubuyy anandd ordeorderr througthroughh th thee mail rrtilil.. If1£ yo youu collect collect,, cut cut,, o orr desig designn jewelr jewelryy wit withh gemgemss anandd mineralsminerals,, yoyouu won'won'tt wanwantt t oto mis misss anothe anotherr issue issue.. SubscribSubscribee todatodayy bbyy sendinsendingg uuss youyourr namnamee andand addresaddresss wit withh paymen paymentt toto:: LapidaryLapidary JournalJournal,, P.O P.O. Bo. Box x124-JG, 124-JG D, evoDevonn, PA, P A 1933319333.. YouYourr subscriptiosubscriptionn iiss payablpayablee iinn U.SU.s.. dollardollarss onlyonly.. $3$333 a a yea yearr fo forr surfac surfacee maimaill $6$655 a a yea yearr fo forr ai airr mai maill IncludeIncludess ou ourr Internationall Internationallyy Acclaime Acclaimedd AnnualAnnual Buyers' Buyers' GuideGuide..

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BOOKSBOOKS FROMFROM WILEWILEYY ......

THETHE COWURSCOLOURS OFOF OPAQUEOPAQUE ATLAATLASS OFOF OPAQUEOPAQUE ANANDD OREORE MINERALSMINERALS MINERALSMINERALS ININ THEIRTHEIR AA.. PeckettPeckett,, UniversitUniversityy ooff DurhamDurham,, UUKK ASSOCIATIONSASSOCIATIONS ColouColourr iiss ththee mostmost obviouobviouss propertpropertyy thathatt ththee ororee R.AR.A.. IxerIxer,, BirminghamBirmingham University,University, UUKK microscopismicroscopistt useusess iinn thethe identificationidentification ofof 0pl!queopaque TheThe identificationidentification ofof ororee mineralsminerals requiresrequires aa mineralsminerals.. ThiThiss bookbook setssets outout ttoo answeanswerr ththee quesques trainetrainedd eyeeye thathatt cancan recognizerecognize ththee subtlesubtle differdiffer tion,tion, WhWhyy dodo particularparticular opaquopaquee mineralsminerals havhavee encesences betweenbetween mineralsminerals.. TrainingTraining studentsstudents (an(andd colourscolours wewe see?see? ThisThis includeincludess notnot onlyonly ththee professionals)professionals) iinn thisthis skillskill hashas traditionallytraditionally beenbeen coloucolourr seenseen iinn planplanee polarizepolarizedd light,light, bubutt alsalsoo ththee difficultdifficult --partlpartlyy becausbecausee ooff ththee lacklack ooff a colourcolour colourscolours ofof anisotropicanisotropic mineralmineralss viewedviewed betweenbetween guideguide ttoo thethe characteristicharacteristicc opticaloptical propertiepropertiess anandd crossedcrossed oorr slightlyslightly uncrosseuncrossedd polarspolars.. texturetexturess ooff ororee mineralmineralss andand ore-associations.ore-associations. BeginninBeginningg withwith aann explanationexplanation ooff thethe physiologiphysiologi OnOnee particulaparticularr probleproblemm iiss thathatt thethe samesame mineraminerall calcal aspectaspectss ooff coloucolourr perceptioperceptionn andand ththee CIcmE cacann appeaappearr toto bebe opticallopticallyy quitquitee differendifferentt iinn difdif (Commission(Commission InternationalIntemationalee ddee l'Eclairage)l'Eclairage) ferentferent associations.associations. numerical colour specification, the text goes on numerical colour specification, the text goes on ThiThiss boobookk provideprovidess a wealthwealth ooff fullfull colourcolour to examine in detail the physics of the interaction to examine in detail the physics of the interaction photomicrographsphotomicrographs ooff ththee majomajorr ore-formingore-forming of light with minerals and how the optical of light with minersls and how the optical associationsassociations anandd opaquopaquee mineralmineralss iinn non-mineralnon-mineral propertiesproperties ofof sectionssections cancan bbee explaineexplainedd inin termtermss izedized rocksrocks.. TheThe authorauthor describesdescribes typicatypicall examexam ofof ththee dispersiondispersion ofof ththee relativrelativee permittivitypermittivity plesples ooff eaceachh materiamateriall fromfrom manymany classicaclassicall localilocali tensor.tensor. tiesties throughoutthroughout ththee worldworld.. Also,Also, foforr eacheach associassoci A majomajorr parpartt ofof thethe boobookk containscontains descriptionsdescriptions ooff atioationn therethere isis texttext listinlistingg thethe majomajorr (and(and imporimpor thethe crystalcrystal structuresstructures andand opticaloptical propertiepropertiess ooff tantantt minor)minor) primaryprimary oreore mineralsminerals,, alterationalteration somesome 170170 ororee mineralmineralss and,and, wherewhere knownknown,, theitheirr productproductss anandd gangue,gangue, typicaltypical textures,textures, a briefbrief electronicelectronic structuresstructures.. discussiondiscussion ooff ththee geologgeologyy ofof ththee associatioassociationn andand a 04719334704719334733 550pp550pp DeDecc »9'911 £95.001$203.00£95.00/$203.00 lislistt ofof references.references. 04719322990471932299 208pp208pp OcOctt '9'900 £95.001$202.15£95.00/$202.15 GEMOLOGYGEMOLOGY Formerly published published by by Open Open University University Press. Press. 2nd Edition 2nd Edition ORESORES ANDAND MINERALSMINERALS EditedEdited byby C.S.CS. Hurlbut,Hurlbut, Jr.Jr.,, HarvarHarvardd University,University, anandd R.CR.C.. Kammerling,Kam mer ling, IntroducingIntroducing EconomiEconomicc GeologGeologyy GemologicalGemological InstitutInstitutee ofof America,America, J.WJ.W.. BarnesBarnes,, UniversityUniversity CollegeCollege ooff California,California, USUSAA Swansea,Swansea, UUKK ThiThiss newnew editioeditionn ooff ththee ververyy successfulsuccessful Gemolo WritteWrittenn foforr studentsstudents takintakingg theitheirr firstfirst anandd perhapperhapss gy wilwilll bebe aann invaluablinvaluablee sourcesource ofof informationinformation onlonlyy courscoursee iinn geologygeology,, thithiss bookbook givegivess a broabroadd foforr jewelerjewelerss anandd collectorscollectors anandd anan outstandingoutstanding understandingunderstanding ooff thethe far-reachingfar-reaching practicapracticall referencereference workwork forfor professorprofessorss andand studentsstudents iinn importanceimportance ooff thethe subjectsubject.. gemologygemology courses.courses. ItItss generagenerall approachapproach anandd ShowingShowing howhow geologgeologyy enableenabless usus ttoo findfind anandd ordeorderr areare thethe samesame aass ththee firsfirstt editionedition:: discussiondiscussion exploiexploitt ouourr mineraminerall resourcesresources,, ththee boobookk demondemon ooff ththee origioriginn anandd occurrenceoccurrence ooff gegemm mineralmineralss areare stratesstrates ththee centracentrall rolrolee ooff geologgeologyy iinn meetinmeetingg ththee followedfollowed byby chapterschapters onon ththee chemicalchemical,, crystallocrystallo- demanddemand forfor metalsmetals,, fuelsfuels,, petrochemicalspetrochemicals,, aggraggr- graphicgraphic,, physicaphysicall anandd opticaopticall propertiesproperties.. SinceSince iitt gatesgates,, industriaindustriall mineralsminerals,, andand inin manymany partpartas ooff isis thesethese propertiepropertiess thatthat characterizcharacterizee anandd identifyidentify ththee worldworld,, waterwater.. gemsgems,, emphasisemphasis iiss placedplaced onon ththee methodmethodss anandd 04719320304719320355 192pp192pp (pr)(pr) 19881988 £14.951$31.85£14.95/$31.85 instrumentsinstruments useusedd inin theirtheir determination.determination. 04719320404719320433 192pp192pp (el)(cl) 19881988 £39.001$83.00£39.00/$83.00 TechnologicalTechnological developmentsdevelopments havehave beebeenn applieappliedd ttoo Formerly published published by by Open Open University University Press. Press. manmanyy areasareas ooff gemology,gemology, andand thithiss editioeditionn totallytotally reviserevisess anandd updateupdatess thethe materialmaterial iinn importanimportantt Wiley books books are are available available through through all major all major booksellers. booksellers. areasareas,, includingincluding:: GeGemm synthesis,synthesis, ImitatioImitationn gems,gems, Alternatively order order direct direct from from Wiley Wiley (payment (payment to John to John GemstoneGemstone enhancement,enhancement, MagnificationMagnification anandd NeNeww Wiley &: & Sons Sons Ltd). Ltd). Credit Credit card card orders orders accepted accepted by by gemsgems.. telephone - -(0243) (0243) 829121 829121 or FREEFONEor FREEFONE 3477. 3477.Please Please note that prices quoted here apply to UK and Europe TheThe previousprevious editionedition ofof thisthis boobookk wawass publishedpublished :;".J;. that prices quoted here apply to UK and~E~urope inin 1979.1979. JOHNJOHN WILEWILEYY & SONSSONS LTDLTD [\X/l 04715266730471526673 350pp350pp MarMar'9 '911 £53.001$79.95£53.00/$79.95 V V A Wiley USA Tille.Title. BAFFINSBAFFINS LANEUNE,, CHICHESTERCHICHESTER,, V I 1 WES~TSUSSEX.P0191UDT SUSSEX, P019 1UD V«L^ WILEYWILEY 121288 JJ.. Gemm.Gemm.,, 19921992,23,, 23, 2

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ADVERTISING IN Rates per insertion, excluding THE JOURNAL OF VAT, are as follows: GEMMOLOGY Whole page £180 Half page £100 The Editors of the Journal invite Quarter page £60 advertisements from gemstone and mineral dealers, scientific Enquiries to Mrs M. Burland, instrument makers, publishers Ad vertising Manager, and others with interests in the Gemmological Association, gemmological, mineralogical, 27 Greville Street, lapidary and jewellery fields. London ECIN 8SU. Volume 23 No. 2. Aprü 1992

1 heJournal of Gemmology

Contents

Vanadian grossular garnet (tsavorite) from Pakistan B. Jackson 67 An examination of'Aqua Aura' enhanced fashioned gems R. C. Kammerling and John L Koivula 72 A Book Anniversary R. K. Mitchell 78 Radioactive glass imitation emeralds and an unusual Verneuil synthetic ruby J. M. Duroc-Danner 80 The French Connection A. F, Farn 84 On the properties of meteoritic gem olivine from a pallasite from

Esquel3 Patagonia, Argentina U. Henn and A. F. A. Becker 86

The Museum of Ouro Preto, Minas Gerais3. Brazil F. M. Bastos 89 Lamellar inclusions in spinels from Morogoro area, Tanzania K. Schmelzer and A. Berger 93 Determination of dispersion using a refractometer W. W. Hanneman 95 Magnetic resonance distinction between synthetic and natural 'padparadscha' sapphires G. J. Troup, D. R. Hutton and B. Turner 97 Gemmological Abstracts 103 Book reviews Proceedings of The Gemmological Association and Gem Testing Laboratory of Great Britain and Notices Letter to the Editor

ISSN: 0022-1252

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