The Journal of Gemmology

Home , Atocha Star Emerald, Babingtonite, Chrysoprase, Gormanite, Larimar, Sugilite

Volume 22 No. 6. April 1991 The Journal of Gemmology

THE GEMMOLOGICAL ASSOCIATION AND GEM TESTING LABORATORY OF GREAT BRITAIN OFFICERS AND COUNCIL

Past Presidents: Sir Henry Miers, MA, D.Sc, FRS Sir William Bragg, OM, KBE, FRS Dr. G.E Herbert Smith, CBE, MA, D.Sc. Sir Lawrence Bragg, CH, OBE, MC, B.Sc, FRS Sir Frank Claringbull, Ph.D., Elnst.E, FGS Vice-President: R. K. Mitchell, FGA

Council of Management D.J. Callaghan, FGA N.WDeeks,FGA N.B. Israel, FGA E.A. Jobbins, B.Sc, C.Eng., FIMM, FGA I. Thomson, FGA V.E Watson, FGA K. Scarratt, FGA : Chief Executive R.R. Harding, B.Sc, D.Phil., FGA : Director of Gemmology

Members' Council A. J.Allnutt,M.Sc, D. Inkersole, FGA PG. Read, C.Eng., Ph.D., FGA B. Jackson, FGA MIEE, MIERE, FGA C. R. Cavey, FGA G.H. Jones, B.Sc, Ph.D., FGA I. Roberts, FGA R J. E.Daly, B.Sc, FGA H. Levy, M.Sc,BA, FGA E.A. Thomson, T. Davidson, FGA J. Kessler Hon. FGA R. Fuller, FGA G. Monnickendam R. Velden J.A.W Hodgkinson, L. Music D. Warren FGA J.B. Nelson, Ph.D., FRMS, CH. Winter, FGA FInst.P, FGA

Branch Chairmen: Midlands Branch: D.M. Larcher, FBHI, FGA North-West Branch: W Franks, FGA

Examiners: A. J. Allnutt, M.Sc, Ph.D., FGA D. G. Kent, FGA E. M. Bruton, FGA P Sadler, B.Sc, FGS, FGA C. R. Cavey, FGA K. Scarratt, FGA A. E. Farn, FGA E. Stern, FGA R. R. Harding, B.Sc, D.Phil., FGA M. Virkkunen, M.Phil., FGA E. A. Jobbins, B.Sc, C. Eng., FIMM, FGA C.Woodward, B.Sc, FGA G. H. Jones, B.Sc, Ph.D., FGA

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

The Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street, London EC1N 8SU Telephone: 071-404 3334 Fax: 071-404 8843 """Journal of G^nmology

VOLUME 22 NUMBER SIX APRIL 1991

Cover Picture A crystal of emerald on calcite from Muzo, Colombia, from The Mineral Collection, Federal Institute of Technology, Zurich, presented and photographed by Dr E. Giibelin of Meggan, Switzerland.

ISSN: 0022-1252 330 J. Gemm., 1991,22,6

Sir Frank Claringbull 1911-1990

was well equipped for the rapid analysis of minerals and rocks. X-ray diffraction was followed by X-ray fluorescence and with great prescience he sent one of his staff to Cambridge to collaborate in the development of the electron-microprobe for use on minute mineral grains. In many of his scientific papers Claringbull worked with Dr M.H. Hey, the Museum expert on microchemical analyses; he also collaborated with B.W. Anderson and C.J. Payne of the Gem Testing Laboratory. In 1951 this quartet elucidated the nature of the spinel-like mineral, taaffeite, which had been found as a gemstone by Count Taaffe in a jeweller's junk box in Dublin. In 1952 Claringbull and Hey announced the discovery of the new mineral, smhalite, which had previously lurked as a 'brown olivine' gemstone and had been viewed with suspicion by Anderson and Payne and by G. Switzer of the US National Museum in Washington. In 1956 Claringbull, Hey and Payne announced the discov ery of another new mineral, painite, found as a crystal by A.CD. Pain at Mogok in Burma and named in his honour. Claringbull worked on many other minerals and this is reflected in a series of It is with great regret that we report the death, on 23 papers in the mineralogical journals. Claringbullite, November 1990, of Sir Frank Claringbull, an a new hydrated copper chloride mineral, was named Examiner from 1938 to 1970 and President of this in his honour in 1977. Association from 1972. He had been in ill-health for In 1968 Claringbull was appointed Director of some years. the Museum, and his experience in the reopening of Gordon Frank Claringbull, B.Sc, Ph.D., the famous Mineral Gallery (now threatened with FInst.P, FGS, Born 21 August 1911, was educated closure) stood him in good stead. The attention to at Finchley Grammar School and then at Queen detail, so necessary in that exhibition, was to be of Mary College, University of London, where he immense value in the wider tasks ahead. The 'Hall gained first class honours in geology. This was of Human Biology', opened in 1977, was the first of followed by the award of Ph.D. for his study of the 'new'exhibitions developed under his direction; igneous rocks in the Balmoral area, Aberdeenshire. it was widely popular, especially with the young He joined the staff of the British Museum (Natural who did not mind the somewhat cramped viewing History) in 1935 and worked there, apart from the space and the paucity of natural specimens. war years, until his retiral in 1976. Initially he Claringbull was a man of bustling activity with a worked under Dr Campbell Smith on curatorial constant desire to finish the work in hand as soon as duties with the rock collections and continued his possible. As Secretary of The Mineralogical Society studies of Scottish rocks. for many years he was immensely efficient and a During the war he moved to Birmingham where great stickler for punctuality at meetings. He was he worked on the crystallography and the develop eminently fair and one former member of the old ment of explosives for the Special Operations Geological Museum staff can recall being in a Executive. somewhat tense dispute in the Keeper's room with Following his return to the Museum in 1945 he four members of the BM staff when Claringbull worked with Dr FA. Bannister on the development observed that 'four of us to one of him' was not fair of X-ray diffraction methods for the identification odds. of minerals. After his appointment as Keeper of His wife, Enid, son and daughter survive him. Minerals in 1953 he ensured that his department E.A.J. JJ.. Gemm.Gemm.,, 1991,22,61991,22,6 331331

PocahontasPocahontas A.E.A.E.Farn Farn

Seaford,Seaford, EastEast SussexSussex

I votedvoted forfor thethe mergermerger ofof TheThe GemmologicalGemmological I felt,felt, somewhatsomewhat righteously,righteously, thatthat I waswas reallyreally a AssociatioAssociationn withwith TheThe LaboratoryLaboratory becausbecausee iitt seemedseemed colourecolouredd stonestone mamann anandd hahadd onlonlyy undertakenundertaken pearlpearl inevitablinevitablee andand,, frankly,frankly, sensible.sensible. I dididd so,so, though,though, testingtesting becausbecausee ooff thethe retiremenretirementt ooff Anderson,Anderson, nonott withoutwithout regretregret aatt ththee passinpassingg ofof twotwo distinctdistinct yeyett PaynePayne andand WebsterWebster.. TheThe newnew staffstaff hadhad nnoo experiexperi analogouanalogouss bodiesbodies.. BotBothh werewere ververyy importanimportantt iinn mymy enceence witwithh pearlspearls anandd soso itit wawass inevitableinevitable thatthat I diddid workingworking lifelife asas a tradetrade gemmologistgemmologist.. WhenWhen I retired,retired, ththee pearpearll testintestingg - whichwhich becambecamee mymy metiemetierr - and,and, a previousprevious chairmanchairman ofof TheThe PreciousPrecious StoneStone TradeTrade ofof course,course, ththee bookbook.. I soughtsought asas manmanyy referencesreferences asas SectionSection saidsaid thathatt iitt was thethe endend ooff aann era,era, i.ei.e.. possiblepossible,, nonott jusjustt oonn pearlspearls,, bubutt onon equipment,equipment, Anderson,Anderson, PaynePayne,, WebsterWebster andand Farn.Farn. I feltfelt thethe samesame X-raX-rayy productioproductionn andand ththee biologbiologyy ooff oysteroysterss (scal(scal wayway aboutabout ththee mergermerger.. NoNoww wwee havhavee a newnew beginbegin lopslops really)really).. BeingBeing a pearpearll tester,tester, howevehoweverr efficient,efficient, ningning anandd fresfreshh fieldfieldss ttoo conquer.conquer. doesn'doesn'tt makmakee oneone intintoo a marinmarinee biologistbiologist.. A goodgood SettingSetting abouaboutt a clearanceclearance ofof manmanyy oldold paperpaperss ooff editoreditor iiss mosmostt usefuusefull sincesince grammar,grammar, punctuationpunctuation thethe nonoww defuncdefunctt GA,GA, I camecame acrossacross thethe minuteminutess ofof a andand nomenclature,nomenclature, alalll makemake theirtheir demands.demands. I wawass GAGA councicouncill meetinmeetingg oonn 2288 FebruaryFebruary 1989.1989. OneOne ooff workinworkingg aatt homhomee anandd ououtt ooff touchtouch withwith laboratorylaboratory ththee mattermatterss discusseddiscussed wawass The Journal; ththee thirdthird facilities.facilities. andand lastlast paragrapparagraphh containecontainedd ththee following:-following :- DelvingDelving intointo ththee literaturliteraturee ofof DakinDakin,, Jameson,Jameson, "Mr"Mr JobbinJobbinss alsalsoo requestedrequested mormoree contributionscontributions andand KunKunzz andand Stevenson,Stevenson, I wawass impresseimpressedd bbyy theirtheir frofromm thethe membershipmembership forfor the Journal, promisingpromising eruditionerudition.. I beganbegan toto realiserealise hohoww poopoorr wawass mymy thathatt allall woulwouldd bebe lookedlooked atat sympatheticallsympatheticallyy anandd theythey geographygeography,, howhow lackinglacking mymy knowledgknowledgee ooff historyhistory neeneedd nonott bbee totooo 'learned''learned' oror contentioucontentiouss toto bebe anandd hohoww weaweakk was mmyy schoolboyschoolboy FrenchFrench.. I waswas included.included."" amazedamazed atat thethe ingenuityingenuity ofof FrenchFrench workersworkers,, inin I tooktook considerableconsiderable heartheart fromfrom thisthis refreshingrefreshing particulaparticularr iinn tacklingtackling ththee probleproblemm ofof detectingdetecting aspecaspectt ooff the Journal's readingreading mattermatter anandd feltfelt 'not'not cultureculturedd pearlspearls.. I learnelearnedd afresafreshh ooff ChilowskiChilowski andand totooo learned'learned' anandd hopefullyhopefully notnot veryvery contentious.contentious. PerrinPerrin,, SimonSimon anandd ReneeRenee Bloch,Bloch, anandd readread veryvery ThThee longerlonger oneone iiss separatedseparated frofromm ththee gemmologemmolo slowlyslowly thethe recordedrecorded observationsobservations ooff J.J. GalibourgGalibourg gicagicall scenescene anandd thethe leslesss ononee practisepractisess gegemm testing,testing, anandd F.E RyzigerRyziger (1927).(1927). TheiTheirr workwork embraceembracedd densidensi ththee soonersooner accumulateaccumulatedd knowledgknowledgee disappears.disappears. BBee tyty,, structure,structure, transparencytransparency toto lightlight rays,rays, penetrationpenetration thathatt aass itit maymay,, I havehave beebeenn thinking,thinking, nonott ooff bbyy X-rayX-rayss andand howhow lightlight travelletravelledd concentricallconcentricallyy inin gemstones,gemstones, bubutt ooff pearlpearlss anandd somesome interestinginteresting pearlpearlss andand alonalongg layerlayerss iinn mother-of-pearlmother-of-pearl.. KnowKnow parallelparallelss oror connectionconnectionss witwithh themthem.. ItIt seemsseems I mademade ledgeledge ofof thethe subjectsubject mattematterr andand gemmologgemmologyy helpedhelped a literaryliterary contactcontact withwith anan aspectaspect ofof theirtheir historyhistory iinn thethe translation.translation. OlOldd hahatt iitt maymay bbee bubutt thethe whenwhen I receivereceivedd a boobookk fromfrom a favouritfavouritee aunauntt oonn mymy endoscopendoscopee aass usedused bbyy ththee FrenchFrench anandd EnglishEnglish ninthninth birthdaybirthday.. ThThee boobookk wawass entitleentitledd 'Captain'Captain laboratorieslaboratories was 100%100% accurateaccurate inin testintestingg drilleddrilled John Smith'. MMyy auntaunt was a maidenmaiden ladylady namednamed (necklace(necklace)) pearlspearls.. UndrilleUndrilledd pearlpearlss succumbedsuccumbed toto EmilyEmily ChattertoChattertonn (the(the namnamee E.E. ChattertonChatterton iiss ooff thethe penetratiopenetrationn ooff X-rayX-rayss thankthankss ttoo ththee worworkk ooff interest).interest). ThThee boobookk wawass writtenwritten bbyy E.E. ChattertonChatterton RontgenRontgen,, VonVon LaueLaue,, DauvillierDauvillier,, ShaxbyShaxby andand bubutt atat ththee momenmomentt ooff writinwritingg therethere isis nono immediateimmediate DoelterDoelter.. importancimportancee ttoo bbee attacheattachedd ttoo thethe coincidencecoincidence.. TheThe WheWhenn I needeneededd ttoo finfindd ououtt abouaboutt historical/historical/ book'sbook's contencontentt atat ththee timtimee wawass above mmyy heaheadd eveneven famoufamouss pearlspearls and,and, iinn particularparticular,, thethe sourcessources ooff thougthoughh I waswas aann omnivorouomnivorouss readerreader forfor mymy age.age. I letlet pearlspearls,, I turneturnedd ttoo The Book of the Pearl bbyy KunzKunz itit bbee forfor a couplcouplee ofof yearsyears anandd thethenn enjoyedenjoyed it.it. anandd Stevenson.Stevenson. ThiThiss waswas a veritablveritablee minemine ooff inin AbouAboutt sixtysixty yearsyears later,later, iinn retirement,retirement, I wawass formationformation - iiff oneone cancan havehave a minminee forfor pearlspearls.. WhenWhen approachedapproached ttoo writewrite a monograpmonographh onon pearlspearls.. ItIt wawass I camecame toto thethe pearlspearls ofof thethe Americas,Americas, viz.viz. Panama,Panama, somethingsomething thatthat I hahadd neveneverr seriouslyseriously contemplated.contemplated. Venezuela,Venezuela, MexicoMexico,, VirginiVirginiaa anandd thethe MississippiMississippi

Valley, I was stopped in my tracks. Here was My wife comes from a north Norfolk village not reported the account of Captain John Smith who set far from Heacham. Typing the details of Virginia out in 1605/6 to colonize Virginia, the same man as (sources of pearls) for the book she remembered a in my boyhood book. I felt This is where I came in'. school friend from Heacham who had pointed out a Captain John Smith was a remarkable man. Born house at Heacham where it was said an Indian in Willoughby, Lincolnshire, in 1579, he was an princess had lived long ago. She had married into apprentice in King's Lynn (Norfolk). He then went the Rolfe family who were an old and important abroad as a mercenary and served four years with family in Heacham. the French army. Later he fought with the Last month we had a holiday in north Norfolk, Austrians against the Turks in Transylvania. Taken re-visiting old haunts. We decided to visit Heacham prisoner, he was sent to Constantinople as a present because of my interest in Pocahontas, pearls and to the wife of a local Turkish pasha. She feared for Captain John Smith. In Heacham parish church his safety and sent him to Varna on the Black Sea, were many engraved tablets and memorial stones to where he was a slave. He killed his master and members of the Rolfe family who had nobly served escaped to Western Europe and returned to Eng their king and country over hundreds of years. In land in 1604. Here he joined a London company the poor light of the interior I could see a bas-relief expedition to colonize Virginia. Three ships plus a sculpted bust of Pocahontas which had been pre hundred or so migrants set sail from Blackwall late sented to the church by American visitors who in December 1606 under licence from James I. claimed to be descendants of Rolfe's grand They landed in Virginia in May 1607. Here they daughter Jane. We also obtained a short account of founded the settlement of Jamestown on the James Pocahontas written by Jane Neville Rolfe. She was river; both were so named in honour of King James the last member of the family in Heacham and died I of England. In his notes Captain Smith mentions in 1989 aged seventy-nine. A private burial plot the importance that the tribes of the tidal water enclosing many tombs and memorials of the Rolfe region placed upon pearls for adornment. Some family is surrounded by a close clipped yew hedge, thirty tribes of Algonquin Indians were ruled by a bringing strongly to mind that excerpt from Tho powerful chief named Powhatan. He was not happy mas Gray:- with the presence of the white settlers and at one "Beneath that elm, that yew tree's shade time took Smith prisoner with intent to kill him. Where heaves the turf in many a mouldering heap Smith's life was saved by the intervention of Each in his narrow cell forever laid Pocahontas, the daughter of Powhatan. She was The rude forefathers of the hamlet sleep." about twelve years of age. A few years later among Returning albeit briefly to my working life, it the additions to the settlement was John Rolfe, a seems strange now to think of the hundreds of times graduate seeking his fortune in Virginia; his ship en route for the Laboratory from Cannon Street had been wrecked on the Bermudas. Rolfe came Station I passed by the Wren church (1680) of St from Heacham, a village on the north Norfolk Mary-le-Bow, Cheapside. Usually it served to re coast; he experimented with tobacco planting. mind me that my mother's family were true Cock Following various affrays with the Indians, Poca neys, having been born not a stone's throw from hontas was held hostage, but was well treated. She Hatton Garden, within the sound of Bow Bells. My received religious instruction and was eventually grand-father worked in Mitre Court at the end of baptised Rebecka. She married John Rolfe in 1614 Hatton Garden. In Wren's churchyard stands a and their son was born the following year. A year statue to Captain John Smith. It bears the following later in 1616 they sailed for England, first visiting inscription: "Citizen and Cordwainer (1580-1631). Heacham to see his mother before being presented First among the leaders of the settlement at James at the court of King James and his consort Queen town, Virginia, from which began the expansion of Anne. Pocahontas found England's climate chilly, the English speaking peoples". with London wet and smoky, and was in poor A few hundred yards westward towards the health. John Rolfe was appointed Secretary and Laboratory stands St Sepulchre's Church at the Recorder General of the Virginia colony. In March junction of Holborn Viaduct (London's first flyover, 1617 they set out for the return to Virginia but were 1866) and Newgate Street; here Smith was buried. held up at Gravesend. Here Pocahontas died; she It seems a little ironic when I recall that my main was twenty-two years of age. She was buried in St. memory of St Sepulchre's stems from a drinking George's church, Gravesend. Rolfe eventually re fountain set in the corner of a wall. It was carved, I turned to Virginia where he died in a massacre in believe, from reddish serpentine from the Lizard, 1622; his son who had remained in England went to Cornwall. Virginia when he was twenty-five. He had one Development has removed or obscured many daughter, Jane. facets of Old London. Development is one of those J. Gemm., 1991, 22, 6

words bracketed to or which has a connotation with mergers and 'the end of an era'. On Wednesday, 3 May 1989, at 11.00 hours, Long Wave, the BBC broadcast an excellent programme on Radio 4. It was entitled The Peace of Poca hontas'. [Manuscript received 15 October 1990.] I RAYNER ILLUMINATED REFRACTOMETER An instrument essential for Gem Testing and Jewellery Valuations.

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GEMMOLOGICAL INSTRUMENTS LTD A division of The Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street, London EClN 8SU. Telephone: 071-404 3334 Fax: 071-404 8843 334334 J.J. Gemm.,Gemm., 1991,22,61991,22, 6

GemGem thaumasitethaumasite fromfrom thethe BlackBlack RockRock MineMine,, SouthSouth MricaAfrica Ulrich Henn, Markus Redmann and Hermann Bank Ulrich Henn, Markus Redmann and Hermann Bank German Foundation for Gemstone Research, 6580 Idar-Oberstein, Germany German Foundation for Gemstone Research, 6580 Idar-Oberstein, Germany

IntroductioIntroductionn basibasicc metamorphicmetamorphic rocksrocks (e.g.(e.g. HungaryHungary,, Austria,Austria, ThaumasiteThaumasite iiss a complecomplexx mineraminerall witwithh thethe cheche NeNeww JerseyJersey/USA)/USA),, micamicall formulformulaa CaCa3Si(C03)(S04)(OH)612H20.3Si(C03)(S04)(OH)612H20. TheThe 3.3. inin limestonelimestone contactcontact zoneszones associateqassociated withwith hexagonahexagonall mineralmineral showsshows distincdistinctt cleavagcleavagee parallelparallel amphibole,amphibole, pyroxenepyroxene,, chloritechlorite,, garnet,garnet, idocrasidocrasee andand ttoo thethe verticaverticall prisprismm anandd conchoidaconchoidall fracturefracture;; thethe sporadicsporadic babingtonitbabingtonitee (e.g.(e.g. CzechoslovakiaCzechoslovakia,, USSR,USSR, hardnesshardness iiss 3 1Vi./2. Utah/USAU tahiUSA,, California/USA).California/USA). ThaumasitThaumasitee iiss a typicaltypical neogenicneogenic mineralmineral andand SomeSome occurrencesoccurrences represenrepresentt transitiontransition typestypes,, e.g.e.g. solublesoluble iinn acids.acids. WhitWhitee compactcompact aggregateaggregatess ooff tinytiny MytMy too m;arnear TachovTachov iinn SWSW BohemiaBohemia.. ThatThat localitlocalityy iiss aciculaacicularr oror needle-likneedle-likee crystalcrystalss araree usualusual.. TheThe groupegroupedd witwithh ththee genetigeneticc typetype 33,, bubutt numerousnumerous knowknownn occurrenceoccurrencess cancan bbee dividedividedd intintoo threthreee typestypes:: indicationindicationss (e.g. ththee presencpresencee ofof zeolite)zeolite) showshow closeclose 1.1. associateassociatedd witwithh sulfidicsulfidic oreoress (e.g.(e.g. Sweden,Sweden, TenTen relationrelationss ttoo typtypee 2 (Kourimsky,(Kourimsky, 1977)1977).. nessee/USA)nessee/USA),, EuhedraEuhedrall thaumasitthaumasitee crystalcrystalss ooff remarkablremarkablee sizesize 22.. iinn cavitiecavitiess ooff basibasicc effusiveffusivee rockrockss aass welwelll aass iinn havhavee beebeenn discoverediscoveredd iinn SoutSouthh AfricaAfrica.. ThThee localitylocality iiss ththee BlacBlackk RocRockk MinMinee iinn ththee KalaharKalaharii ManganeseManganese FielFieldd (Figur(Figuree 1)1).. ThaThatt regioregionn iiss welwelll knowknownn forfor occurrenceoccurrencess ooff gegemm sugilitsugilitee (Dun(Dunnn et al,aI., 19801980;; HennHenn,, 19861986;; ShigleShigleyy et ah,aI., 19871987)) anandd transparenttransparent rhodochrositrhodochrositee (Ban(Bankk anandd BeckerBecker,, 1977)1977).. ThThee thaumasite-bearinthaumasite-bearingg manganesmanganesee ore-bodyore-body containcontainss dardarkk browbrownn ttoo blacblackk manganesmanganesee oresores,, especiallespeciallyy hausmannitehausmannite,, psilomelanepsilomelane,, pyrolusitepyrolusite,, bixbyitbixbyitee anandd braunitebraunite.. AdditionallyAdditionally,, manganesemanganese- bearinbearingg garnetgarnetss havhavee beebeenn discovered.discovered.

ResultResultss ooff examinationsexaminations ThThee BlacBlackk RocRockk thaumasitthaumasitee crystalcrystalss investigatedinvestigated araree uupp ttoo 1.1.55 cemm iinn sizsizee anandd shoshoww distincdistinctt hexagonahexagonall FigFig.. 22.. DistincDistinctt growth-zoningrowth-zoningg iinn a BlacBlackk RocRockk thaumasitethaumasite.. prismatiprismaticc habihabitt witwithh welwelll developedevelopedd prisprismm (1010(IOTO)) xlOxlO.. anandd basabasall (0001(0001)) faces.

FigFig.. 33.. DistincDistinctt growth-zoningrowth-zoningg perpendiculaperpendicularr ttoo ththee c-axic-axiss ooff FigFig.. 44.. LiquiLiquidd filmsfilms.. DarDarkk fielfieldd illuminationillumination.. x30x30.. ththee thaumasitethaumasite.. xlOx 10..

~. 30 km .I ( ,- "",," I' I"~' -~~ ! 0~W .I ~ 1.1 ~ .""-' I ",' .". _ ...... tI'

FRYBURG • Wessels Mine Black Rock A • • HOTAZEL

-KURUMAN

OLIFANTSHOEK •

Fig.Fig. I.1. GeographicalGeographical mapmap ofof thethe KurumanKuruman regionregion inin thethe KalahariKalahari ManganeManganessee FieldField withwith thethe BlackBlack RockRock MineMine andand thethe WeWesselsselss MineMine nearnear HotazelHotazel ((afteafterr ShigleyShigley el ai.,al., 19871987))..

Fig. S.5. PrismaticPrismatic negativenegative crystalcrystal filledfilled withwith a liquidliquid andand a gasgas Fig.Fig. 6.6. Bunch-likeBunch-like crystalcrystal inclusions.inclusions. x2S.x25. bubble.bubble. xSO.x50. 333366 JJ.. Gemm.Gemm.,, 19911991,22,6, 22, 6

RefractivRefractivee indicesindices,, birefringencbirefringencee anandd densitdensityy ReferenceReferencess havhavee beebeenn determinedeterminedd aass nno=1.505-1.51O,0= 1.505-1.510, Bank,Bank, H., H., Becker Becker G., G., 1977. 1977. Klar Klar dUrchsichtiger,durchsichtiger, schleifwürdiger schleifwiirdi Rhodochrositger Rhodochrosit aus Hotazell aus Hotazell in Südafrika. in Siidafrika. Z. Dt. Gemmol. Z. Dt. Gemmol. nne=e= 1.467-1.4801.467-1.480,, An=-0.036n= -0.0300 ttoo 0.030.0388 anandd 33 Ges.Ges.,, 2626,157-60., 157-60. D= 1.88-1. 90 g/cm • These data correspond to D= 1.88-1.90 g/cm . These data correspond to DunnDunn,, P.J.P.J.,, BrummerBrummer,, J.J.J.J.,, BelskyBelsky,, H.H.,, 19801980.. SugiliteSugilite,, A SeconSecondd thosthosee ooff thaumasitethaumasitess frofromm variouvariouss localitieslocalities,, pubpub OccurrenceOccurrence:: WesselWesselss MineMine,, KalaharKalaharii ManganesManganesee FieldField,, lishelishedd bbyy KourimskKourimskyy (1977)(1977):: nn0o==1.500-1519, 1.500-1519, RepubliRepublicc ooff SoutSouthh AfricaAfrica.. Canadian MineralogistMineralogist,, 1818,, 37-937-9.. HennHenn,, U.U.,, 19861986.. SugiliSugilitaust aus SüdafrikaSiidafrika.. ZZ.. Dt.Dt. Gemmol. Ges., 3535,, nlle=e= 1.464-1.4761.464-1.476,, An=-0.036n= -0.0311 ttoo 0.0430.043,, D=1.87D= 1.87-- 3 65-765-7.. 1.91.900 g/cm .• KourimskyKourimsky,, J.J.,, 19771977.. ThaumasiThaumasitt vovonn MytMy too bebeii TachovTachov.. Sbornik ThaumasitThaumasitee crystallizecrystallizess iinn ththee hexagonalhexagonal- Narodniho Muzea V Praze -- Acta Musei Nationalis Pragae, pyramidapyramidall crystacrystall classclass;; ththee latticlatticee constantconstantss havhavee XXXIIIBXXXIII B,, NoNo.. 1-21-2,41-52., 41-52. ShigleyShigley,, J.E.J.E.,, KoivulaKoivula,, J.I.J.I.,, FryerFryer,, C.W.C.W,, 19871987.. ThThee OccurrenceOccurrence beebeenn determinedeterminedd aass ao0= 11.077(611.077(6)) A anandd Cco0= 11.412(6) by Guiniertechniques. AnAndd GemologicaGemologicall PropertiePropertiess OOff WesselWesselss MinMinee SugiliteSugilite.. 11.412(6) A by Guinier techniques. GemsGems& &Gemology Gemology,, 2323,, 78-8978-89.. ThThee microscopicamicroscopicall featurefeaturess ooff ththee BlacBlackk RocRockk thaumasitthaumasitee areare:: [[ManuscriptManuscript received 1616 OctoberOctober 1990.]1990.] 11.. distincdistinctt growth-zoningrowth-zoningg paralleparallell (Figur(Figuree 22)) anandd perpendiculaperpendicularr (Figur(Figuree 33)) ttoo ththee c-axic-axiss ooff th thee thaumathauma sitsitee hosthost,, 22.. finfinee liquiliquidd filmfilmss (Figur(Figuree 4)4),, 33.. negativnegativee crystalscrystals,, partiallpartiallyy fillefilledd witwithh liquiliquidd anandd a gagass bubblbubblee (Figur(Figuree 5)5),, 44.. bunch-likbunch-likee inclusioninclusionss (Figur(Figuree 6)6).. J. Gemm., 1991,22,6 337

Gemmological teaching in Catalonia J.B. Nelson, Ph.D., FGS, F.Inst.R, C.Phys., FGA

McCrone Research Associates Limited, 2 McCrone Mews, Belsize Lane, London NW3 5BG

The writer was asked by the Director of the instrument in the hands of a student for the first Escola de Gemmologia, University of Barcelona, time, there should be offered a clear explanation of Spain, if he would like to deliver several lectures on the fundamental mechanics and optics upon which current gemmological topics. The invitation was of the instrument operates. This is most easily done by course eagerly accepted. using simplified, large-scale bench-type apparatus. The first of four lectures was in the nature of a The students, rather than the instructor, must be demonstration of apparatus designed and made by encouraged to manipulate the devices themselves. the writer. These instruments had sprung from a This generates an understanding and confidence, desire to demonstrate the actual physical principles particularly in students whose exposure to even involved in gemstone testing. He has long felt that elementary scientific matters has been lacking. there has been an inadequate practical treatment of These exercises also convey something of the these basic principles in most international gem- beautiful complexity of design and the remarkable mology teaching centres. He believes that before an performances and accuracy of the tools which they instructor places any conventional gemstone testing routinely use. Beginners usually perceive them

Fig. 1. The 'goniometer unit' being demonstrated.

) Copyright the Gemmological Association ISSN: 0022-1252 338 J. Gemm., 1991, 22, 6

observed by excitation in the invisible ultraviolet end of the spectrum. Figure 1 shows the goniometer unit being demonstrated, while Figure 2 shows a Perspex profile mounted on gimbals on the gonio meter circle. In addition to this unit, several Other visual teaching aids were exhibited. One illustrated the formation of on-axis and off-axis conoscopic fi gures. Another employed a horizontal axis immer sion microscope to project images of the internal microstructures of gemstones directly on to a large screen. It enabled any particular image to be isolated from the general optical 'noise', by making controlled movements of the gemstone while im mersed in the optical matching liquid. A particular effort was made to illustrate the increasing interest in the quantitative measurement of the body colour of gemstones. A simple appar Fig. 2. A perspex profile of a 'brilliant' mounted on gimbals on atus allowed the student to produce any surface the 'goniometer' circle. colour at will through the use of both additive and simply as short lengths of capped tubing or oddly- subtractive colour filters. The quantitative aspect shaped boxes with bits of glass embedded in them. was represented by a spinning disc tristimulus Without doubt, the most informative unit de colorimeter. This permitted the student to measure monstrated was a device which the writer calls a the colour of transparent coloured faceted stones 'single-circle goniometer.' and cabochon-cut jade, lapis lazuli, fire opal and It consists of an arrangement of which one part turquoise in terms of the three CIE Tristimulus produces a thin, parallel ribbon of intense white coordinates for both A' and 'C' CIE Illuminants. A light. This narrow beam, or ray, can be directed in partial view of the colorimeter is shown in Figure 3. turn on to a glass prism or diffraction grating or on to various other refracting objects. One of these is a large polished Perspex plate shaped in the form of a brilliant-cut gemstone profile. The unit is thus able to display the simulated optical ray paths of the single ray of white light as it impinges on and enters and leaves the profile when it is turned through 360°. It can also measure the angles between the facets of a variety of polished profiles or the reflecting faces of euhedral crystals, with an accurancy of ± 0.5°. With the help of ancillary attachments, it allows the angular changes of refracted or reflected rays from various pre-aligned crystals and polished prisms of plastic, glass and cubic zirconia to be observed and measured. Such measurements can then yield values of refractive index, birefringence and dispersion using the minimum-deviation method. At the same time, it can demonstrate Snell's Law, the external and internal Brewster angles and Fresnel reflection intensities at angles of incidence from 1° to 89°. The production of colours, by the use of a set of gelatine filters and by selected spectral absorption, using neodymium-doped YAG and glass filters, helps to de-mystify both phe nomena. Here, both diffraction gratings and prisms are used independently. Finally, long-wave ultra violet fluorescence and phosphorescence can be Fig. 3. A simple spinning disc tristimulus colorimeter. J. Gemm.,1991,22,6 339

The second session was an illustrated lecture on but it was not until 1971 that Barcelona's own centre Synthetic diamonds and gemmological methods to was established. This is surprising because Catalo detect them. A polished laser-cut section of a Sumito nia has by far the highest gross domestic product of mo canary-yellow synthetic diamond was exhibited all Spain's seventeen autonomies. Its creation was for microscopic examination, together with a 0.19 largely due to the professional and political skills of carat brilliant-cut stone of the same material. its two founding fathers, Professor Manuel Font- The third lecture dealt with The four optical Altaba and Dr Jose Bosch Figueroa. The syllabus of attributes of a diamond. Each of these (lustre, the courses offered was based upon that of the brilliance, fire and sparkliness) was treated in terms Gemmological Association of Great Britain. Indeed of their physical optics. Other matters which are both gemmologists acted as external examiners for derivative of these attributes were discussed. These the GA Diploma until their retirement in 1987. are odd-number symmetry cuts, the Brewster angle Their successors are Professor Joaquim Nogues refractometer, effects of adhering scattering matter, Carulla and Dr Marius Vendrell Saz, Director and and the possible benefits and disadvantages of Secretary respectively, with Professor Angel Lopez depositing thin films of aluminium on the pavilion Soler serving as part-time professor. The School has facets. Various pieces of apparatus made to illustrate an annual enrolment of about 120 Preliminary, 70 the optical pathways were shown. Diploma and 25 Diamond Course students. The The final lecture concerned The measurement of examinations for the School's own 'Titulo de Gemo- the body colour of gemstones, including diamond. An logo'as well as that of the Diploma of the GA of G.B. account was given of the CIE Tristimulus System, are conducted both in the Catalan and Castillian which is the internationally adopted standard proc Spanish languages. A view of the well-equipped edure for colour measurement. This system is able class-room is shown in Figure 4. The courses are to express any colour quantitatively in terms of only held in the daytime only. three properties, 'hue', 'saturation' and 'luminance'. One of the most remarkable features of the A brief description was given of the apparatus and student enrolment is that by far most of the students techniques developed by the writer for obtaining are gemstone afficionados, collectors, hobby- these CIE colour coordinate numbers for any lapidarists and amateur jewellery makers. Few are faceted gemstone or piece of gemstone 'rough'. actually involved in the jewellery retailing or manu In Barcelona the Catalan language is widely facturing trade. In one sense, this was not too spoken. That Catalan is indeed a curious and surprising. different tongue can be seen from the table below. Barcelona's long prosperity shows in its wide, The terms were solicited from an audience at impressive, super-clean streets and squares which question time following the lecture on diamonds. seethe with people until all hours of the night. It After much good-natured argument, the transla shows in its elegant shops, its new cars and its tions from English of the four optical attributes of a stylish fashions. However, astonishingly few diamond were finally approved. The lack of initial women of any age were seen to wear jewellery, agreement certainly showed up the real difficulties whether gem-set or not. Jewellers shops are scarcely in defining and translating even these few gemmo to be found, apart from shops selling watches and logical terms. silverware. No one who was questioned about this curious state of affairs had a ready, single explana tion. All agreed that it did not exist in Madrid. A few ENGLISH CASTILLIAN CATALAN thought that Barcelona's drug-related street crime, Attribute Propiedad Propietat which peaked two years ago, was responsible, but most were dismissive of this view. Lustre Brillo Lluisor Seemingly in conflict with this observation is the Brilliance Resplendor Resplandor high popular regard for gemmology itself. This was Fire Fuego Foe evident by the fact that the writer's lectures were announced daily in the 'Conferencias' columns of Llambreig Sparkliness Centelleo Barcelona's principal morning newspaper 'La Van- guardia'. Whatever its effect, each session was well These lectures and demonstrations were held in attended in spite of the talks being given in English the lecture hall of the School of Gemmology during and delivered with a heavy Scottish brogue. the 7th to the 9th March, 1989. The School occupies By virtue of its being an integral part of the a large separate enclave within the Geology Faculty University, the School enjoys very considerable of the University. benefits. Its students have instant access to all the Other gemmology teaching centres had already scientific and technical libraries on the campus. All been established in some of the other autonomies, lectures are free. If post-graduate students are 340 J. Gemm., 1991,22,6

ll^v1 at-

Fig. 4. A general view of the well-equipped classroom in the School of Gemmology, Barcelona.

I?*"

, j(p(r i![

'.;;JWf,'|

Fig. 5. Part of the laboratory at Dr Celades Colom's home used by the Club de Talle de Gemas de Barcelona. J. Gemm., 1991,22,6 341

Fig. 6. Professor Lopez, Dr J.B. Nelson and Dr Celades in the laboratory.

research-minded they have the opportunity to make design and make their own jewellery and to display use of expert advice and all the conventional and the faceted and 'cabbed' stones cut by them. The advanced laboratory intrumentation scattered Club members supply their own starting materials throughout the complex. and pay a small annual subscription; otherwise With regard to the research aspects, the staff of there are no fees. The sessions are held throughout the School, since its inception, have produced many the year outside the normal working hours, some original research papers on gemmology, particularly times in week-day evenings. There is a regular in their speciality of diamonds. These have been Saturday and Sunday daytime session covering a published only in the national journal 'Gemologia' total period of about twelve hours. This is especially so that they have not become universally known. useful for those members not living in Barcelona. It This has brought home to them that a European has been found that most members are able to facet journal of gemmology is now a much-needed two gemstones and four cabochons during a week vehicle for disseminating general information, re end's session. search work and news. From their enquiries, many The Club forms a balanced complement to the other European Societies, whose journals, maga formal day-time studies at the School of Gemmolo zines, news-letters and bulletins enjoy only small gy. The faceting instruction is provided by three circulations, would also welcome such a move. They volunteer teachers, two of whom have had commer hope that the spur of the 1992 events in the EEC will cial experience of diamond polishing. Another catalyse the creation of a single uniquely European instructor is responsible for the design, construc journal of gemmology which will bring the various tion and maintenance of the Club's apparatus. All national publications under one banner. four possess the FGA and the School's Titulo do As well as the School of Gemmology, there exists Gemologo'. There is a wide spectrum of members, another important gemmological activity. This is a from retired people to quite young persons. Most non-profit lapidary club. It was started in 1982 by a are collectors, gemmology students from the small group of self-taught amateurs under the School, jewellery professionals and those generally stimulus of an industrial chemist, Dr Roberto interested in the lapidary art as a captivating hobby. Celades Colom. Named the 'Club de Talle de Gemas Since it inception, some 550 members have come to de Barcelona' it is the first enterprise of its kind in the Club. Many who now have their own machines, Spain. Its purpose is to popularise the lapidarist's still come to enlarge their skills and exhibit their art and to encourage hobbyists and amateurs to stones. 342 J. Gemm., 1991, 22, 6

Fig. 7. Dr Celades at one of the busy lapidary classes in his laboratory.

Fig. 8. Mrs Doris Nelson congratulating an 11 year old student who has just given the final polish to a well-made emerald-cut quartz. J. Gemm., 1991,22,6 343

The plans for the future are to maintain these siasm of the students was unmistakable. The City activities, and extend them to deal with more itself is a delight. There are more museums and sophisticated cutting techniques and to promote galleries than in many European Capitals. It has a the formation of similar lapidary teaching centres in magnificent Cathedral in the old town. The uncom Spain. pleted Church of the Sacred Heart, started by Gaudi Dr Celades invited the writer and Professor in the nineteen-twenties in the new city, is truly Lopez Soler together with their wives to attend a breath-taking. The food is superb and the munici week-day evening session in action. The Club pal retail food markets are something we can only premises cover the entire first and second floors of dream about in London. Barcelona's geographical Dr Celades spacious residence in central Barcelona. position in the Mediterranean is an enviable one. It He and his wife occupy the third top floor, where he is situated in a region of great natural beauty. Its has his private laboratory (see Figures 5 and 6). In success as host to the 1992 Olympic Games is Figure 7 he is seen in one of the several laboratories virtually guaranteed. One can only hope to return talking to Professor Lopez Soler and his wife. A soon. view of one.of the faceting benches is shown in Figure 8. The writer's wife is just congratulating an Acknowledgements eleven year old member who at that moment had The writer is indebted to Senor Carlos Baguena- given the final polish to a well-made emerald-cut Canals for the photographs shown in Figures 1, 2 quartz. and 3 and to Professor Nogues Carulla for that of This Barcelona visit was a most enjoyable experi Figure 4. ence for the writer and his wife. The hospitality of our gemmological hosts was massive and the enthu [Manuscript received 3 February 1990.] 344344 J.J. Gemm.,Gemm., 1991,22,61991,22,6

TheThe microscopicmicroscopic determinationdetermination ofof structuralstructural propertiesproperties forfor ththee characterizationcharacterization ofof opticaloptical uniaxialuniaxial naturalnatural andand syntheticsynthetic gemstonesgemstones

PartPart 1:1: GeneralGeneral considerationsconsiderations andand descriptiondescription ofof ththee methodsmethods

Dipl.-Min. Lore Kie/ertKiefert1l and Dr Karl SchmetzelSchmetzer2

IGriffith1Griffith University, University ,Queensland, Queensland, AustraliaAustralia 2Marbacher2Marbacher Str.Str. 22b,22b, D-8067D-8067 Petershausen,Petershausen, GermanyGermany

AbstractAbstract whichwhich areare similarsimilar toto thosethose characteristicscharacteristics obtainableobtainable TheThe mostmost significantsignificant crystalcrystal facesfaces ofof thethe threethree opticaloptical byby X-rayX-ray topography.topography. However,However, thethe applicationapplication ooff uniaxialuniaxial gemgem mineralsminerals corundumcorundum,, berylberyl andand quartz,quartz, aass anan immersionimmersion microscopmicroscopee isis easilyeasily performableperformable inin wellwell asas thethe anglesangles formedformed bbyy thesethese crystalcrystal facesfaces withwith thethe everyevery gemgem testingtesting laboratorylaboratory andand avoidsavoids thethe highhigh c-axisc-axis oror thethe anglesangles formedformed byby twotwo crystalcrystal facesfaces areare costcost ofof anan X-rayX-ray topographytopography facility.facility. given.given. MethodsMethods foforr thethe determinationdetermination ofof thesethese structuralstructural features for facetedfaceted gemstones gemstones in in the the immersion immersion micro microscopeTheTh e aimaim ofof thethe presentpresent publicatiopublicationn isis toto introduceintroduce scope areare described.described. MeansMeans usedused forfor thethe determinativedeterminative a newnew methodmethod forfor thethe determinationdetermination ofof structuralstructural procedureprocedure areare 1)1) a two-axialtwo-axial samplesample holderholder withwith a 360°0 propertiepropertiess likelike straightstraight paralleparallell growthgrowth planesplanes oror dialdial attachedattached toto thethe verticalvertical axisaxis ofof thethe samplesample holderholder andand twintwin boundariesboundaries inin naturalnatural andand syntheticsynthetic gems.gems. InIn 2)2) a rotaryrotary measuringmeasuring ocularocular withwith crosscross hairshairs attachedattached ttoo addition,addition, a secondsecond methodmethod whichwhich waswas alreadyalready thethe eyepieceeyepiece andand a 360°0 dialdial attachedattached toto ththee ocularocular tube.tube. describeddescribed byby oneone ofof thethe authorsauthors (Schmetzer,(Schmetzer, 19851985,, An easyeasy and and generally generally performable performable way way for for a determina a determination1986)1986 ) isis completedcompleted withwith supplementarysupplementary detailsdetails forfor tion ofof allall structuralstructural propertiepropertiess ooff a facetedfaceted gemstonegemstone byby practicapracticall useuse.. an efficient combinationcombination of of both both methods methods is is described. described. ForFor bothboth methodsmethods itit isis necessarnecessaryy toto useuse thethe horizontahorizontall microscopmicroscopee iinn orderorder toto facilitatefacilitate thethe I.I. IntroductionIntroduction applicationapplication ofof anan immersionimmersion cellcell andand immersionimmersion BecauseBecause ofof thethe valuevalue andand demanddemand ofof thethe gemgem liquids.liquids. ForFor thethe olderolder alreadyalready describeddescribed methodmethod a varietievarietiess ofof corundumcorundum (ruby,(ruby, sapphire)sapphire) asas wellwell asas samplesample holderholder withwith oneone verticalvertical andand oneone oror twotwo berylberyl (emerald,(emerald, aquamarine)aquamarine) andand quartzquartz (amethyst,(amethyst, horizontalhorizontal rotationrotation axesaxes isis appliedapplied toto determinedetermine citrine),citrine), anan increasingincreasing numbernumber andand quantityquantity ofof crystalcrystal facesfaces byby measuringmeasuring thethe angleangle betweebetweenn thethe syntheticsynthetic stonesstones ofof thesethese gemgem varietiesvarieties isis produced.produced. opticoptic axis,axis, i.e.i.e. thethe c-axisc-axis ofof opticallyoptically uniaxialuniaxial WithWith improvingimproving techniquestechniques itit isis easyeasy toto growgrow crystalscrystals,, andand familiesfamilies ofof straightstraight parallelparallel growthgrowth syntheticsynthetic gemsgems withwith propertiesproperties similarsimilar ttoo thosethose ooff planesplanes,, oror toto determinedetermine twintwin planesplanes byby measuringmeasuring theirtheir naturalnatural counterpartscounterparts oror eveneven stonesstones withoutwithout thethe angleangle betweebetweenn thethe opticoptic axisaxis andand thethe twintwin plane.plane. anyany significantsignificant inclusionsinclusions ofof diagnosticdiagnostic value.value. PartPart ofof thisthis firstfirst methodmethod asas wellwell asas a detaileddetailed ForFor thisthis reasonreason,, thethe determinationdetermination ofof structuralstructural descriptiondescription ofof oneone distinctdistinct typetype ofof thethe appliedapplied propertiesproperties ofof gemsgems,, suchsuch aass straightstraight growtgrowthh planesplanes samplesample holdersholders werewere publishedpublished byby SchmetzerSchmetzer (1985,(1985, parallelparallel toto externalexternal crystalcrystal facesfaces oror twintwin planes,planes, isis 1986).1986). becominbecomingg increasinglyincreasingly importantimportant asas anan additionaladditional TheThe newnew methodmethod toto determinedetermine structuralstructural propprop andand easilyeasily performableperformable methomethodd forfor thethe distinctiondistinction ofof ertieserties ofof facetedfaceted mituralnatural andand syntheticsynthetic gemstonesgemstones isis naturalnatural andand syntheticsynthetic gemstones.gemstones. InIn additionaddition toto thethe basedbased onon thethe useuse ofof anan eyepieceeyepiece withwith crosscross hairshairs andand increasingincreasing applicaionapplicaion ofof spectroscopicspectroscopic data,data, thesethese a 360°0 dialdial attachedattached toto thethe eyepieceeyepiece tube.tube. WithWith thisthis newnew supplementarysupplementary andand non-destructivenon-destructive technitechni equipmentequipment iitt isis possiblpossiblee toto measuremeasure anglesangles betweenbetween quesques ofof microscopicmicroscopic examinationexamination enableenable thethe deterdeter twotwo differentdifferent familiesfamilies ofof straightstraight paralleparallell growthgrowth minationmination ofof structuralstructural propertiesproperties ofof facetedfaceted gemgem planeplaness independentlyindependently fromfrom thethe orientationorientation ofof thethe stonesstones and,and, thus,thus, revealreveal datadata ofof diagnosticdiagnostic value,value, opticoptic axisaxis ofof thethe crystal.crystal.

TableTable 1:1: SelectedSelected crystalcrystal facesfaces andand anglesangles ofof corundum,corundum, n:a—A1 - Ah03,203, trigonal,trigonal, crystalcrystal classclass D3dD3d ~— 3 3 ~^

NamNamee DesignationDesignation hklhId** angleangle betweenbetween c-axisc-axis andand crystalcrystal faceface (rotation(rotation angleangle 0)5) basalbasal pinacoidpinacoid c (0001)(0001) 90°90° second-ordersecond-order hexagonalhexagonal prismprism a (ll20)(1120) 0°0° positivepositive rhombohedronrhombohedron r (lOTI)(1011) 3204°32.4° negativenegative rhombohedronrhombohedron d (OlT2)(0112) 51.8°51.8° negativenegative rhombohedronrhombohedron yY (OlT5)(0115) 72.5"72.5° n (2243)(2243) 28.8°28.8° w (1121)(1121) 20.1°20.1° ",cond-o,dffsecond-order } vV (4483)(4483) 1504°15.4° hexagonalhexagonal dipyramidsdipyramids z (2241)(2241) 1004°10.4° vV (4481)(4481) 5.2°5.2° w0) (1414283)(1414283) 4.5°4.5° * basedbased onon thethe morphologicalmorphological cellcell withwith a:c = 1:1:1.36 1.3655 (cf.(cf. KleinKlein & Hurlbut,Hurlbut, 1985)1985)

AnglesAngles mademade bbyy twotwo crystalcrystal facesfaces a /\A a' 120°120° cAac Aa 90"90° z/\z'z A z' 121.1 ° cArc Ar 12204°122.4° w A w'w' 124.0°124.0° cAd 141.8°141.8° nAn'n An' 128.0°128.0° cAyc Ay 162.5"162.5° r A. r'r' 86.1°86.1° cAnc An ll8.8°118.8° aAna An 151.2°0 rAnr A n 154.0°154.0° cAwc Aw llO.l°110.1° aAwa Aw 159.9°159.9° dAn 148.0°148.0° cAzc Az 10004100.4°0 aAza Az 169.6°0 rrAd Ad 133.0°133.0°

TableTable 2:2: SelectedSelected crystalcrystal facesfaces andand anglesangles ofof beryl,beryl, Be3AhSi6018,Be3Al2Si60i8, hexagonal,hexagonal, crystalcrystal classclass D6hD6h ~=^ ~m ~ m~

NamNamee DesignatioDesignationn hklhId** angleangle betweenbetween c-axisc-axis andand crystalcrystal faceface (rotation(rotation angleangle 0)5) 0 basalbasal pinacoidpinacoid c (0001)(0001) 90" first-orderfirst-order hexagonalhexagonal prismprism m (1010)(1010) 90°0 second-ordersecond-order hexagonalhexagonal prismprism a (1120)(1120) 00° firstfirst-orde -orderr hexagonalhexagonal dipyramiddipyramid u (lOTI)(1011) 41.41.0 0C0 first-orderfirst-order hexagonalhexagonal dipyramiddipyramid pP (1012)(1012) 60.1060. T second-ordersecond-order hexagonalhexagonal dipyramiddipyramid s (1122)(1122) 45.1045. r * basedbased onon thethe structuralstructural cellcell withwith a:c = 1:0.9961:0.996 (cf.(cf. KleinKlein & Hurlbut,Hurlbut, 1985)1985)

AnglesAngles mademade bbyy twotwo crystalcrystal facesfaces mAm Am' m' 120c0 cAmc Am 90°0 c0 0 a A a' 120 cAac Aa 90° <0 C0 0 m /\A a 150 cAuc A u 131.0 m A u 139.0° cApc Ap 150.1150. V0 mApm Ap ll9.1°119.1° cAsc As 135.10135.T aAsa A s 134.9°0 346346 J.J. Gemm.,Gemm., 1991,22,61991, 22, 6

TablTablee 33:: SelectedSelected crystalcrystal facesfaces anandd angleangless ooff quartzquartz,, Si02, trigonaltrigonal,, crystalcrystal clasclasss D3D3 = 323 2 NamNamee DesignationDesignation hklhkl** angleangle betweebetweenn c-rudsc-axis anandd crystalcrystal facfacee (rotatio(rotationn anglanglee 50)) basabasall pinacoidpinacoid c (0001(0001)) 9090°° first-ordefirst -orderr hexagonalhexagonal prismprism m (1010(lOTO)) 00°° positivpositivee rhombohedronrhombohedron (major rhombohedron)rhombohedron) r (lOTI)(1011) 38.2°38.2° negativnegativee rhombohedronrhombohedron (minor(minor rhombohedron)rhombohedron) z (OlTI)(0111) 38.2°38.2° * basebasedd oonn thethe structuralstructural celcelll withwith axa:c = 1:1:1.10 1.1022 (cf.(cf. KleiKleinn & Hurlbut,Hurlbut, 1985)1985)

AngleAngless mademade bbyy twotwo crystacrystall facesfaces

m /\Am' m' 120°120° cAmc Am 9090°° rArr A r'' 94.294.2°° cArc A r 128.2°128.2° mArm A r 141.8°141.8° rrAz A z 133.7°133.7° (adjacent)(adjacent) ccAz Az 128.2°128.2° m /\A zz 141.8°141.8° rrAz' /\ z' 76.476.4°° (opposite)(opposite)

IInn a secondsecond andand thirthirdd parpartt ofof thithiss publicationpublication,, thethe authorauthorss discussdiscuss somesome fieldsfields ooff applicatioapplicationn inin detail,detail, formeformedd bbyy twtwoo distincdistinctt crystalcrystal facefacess araree fixefixedd andand e.g.e.g. thethe determinationdetermination ooff crystacrystall facefacess andand twinningtwinning welwelll knowknownn forfor thethe threthreee mineralmineralss [Tables[Tables 1,1, 2 andand iinn naturanaturall anandd syntheticsynthetic emeralemeraldd (part(part 22)) asas wellwell asas inin 3].3]- sapphire,sapphire, rubyruby,, amethysamethystt anandd citrincitrinee (part(part 3).3). TheseThese UnderUnder microscopimicroscopicc observation,observation, ththee anglesangles structuralstructural propertiepropertiess araree stronglystrongly dependentdependent onon formeformedd bbyy twtwoo crystacrystall facesfaces areare directldirectlyy visiblevisible and,and, growthgrowth conditionsconditions appliedapplied foforr ththee productionproduction ooff thusthus,, areare usedused iinn thisthis publicationpublication.. IInn general,general, thesethese syntheticsynthetic gegemm materialsmaterials asas welwelll aass dependendependentt onon thethe angleangless araree designatedesignatedd 4>',<£', whereaswhereas thethe usualusual crystalcrystal- conditioncondition ooff formationformation ofof naturanaturall gemgem minerals.minerals. TheThe lographilographicc literaturliteraturee workworkss withwith interfaciainterfaciall angleangless 'c/;' exampleexampless araree designeddesigned toto provprovee thethe applicabilityapplicability ooff withwith 4>'c/;' = 180°180° - cf;4> [Figure [Figur e 1].1] .However, However , ini n thethe twotwo methodsmethods describedescribedd bbyy ththee authorauthorss foforr a microscopicmicroscopic investigatioinvestigationn a directdirect observatioobservationn ooff characterizatiocharacterizationn ofof naturalnatural anandd syntheticsynthetic gemgem- thethe tracestraces ofof crystalcrystal facesfaces iiss possiblpossiblee anandd thereforetherefore stones,stones, anandd ththee applicatioapplicationn ofof somesome ooff thesthesee datadata toto ththee anglanglec/;',e ', which whic ish formedis forme directlyd directl byy b twoy tw crystalo crysta l problemproblemss ooff ththee determinationdetermination ofof samplessamples ooff unun facefacess isis useusedd withinwithin thithiss seriesseries ooff publications.publications. knowknownn na~ure.nature. IInn FigureFigure 2 a cross-sectioncross-section throughthrough a hexagonalhexagonal oror trigonatrigonall crystalcrystal iiss shown.shown. ThThee morphologmorphologyy ofof thethe crystacrystall isis formedformed byby thethe basalbasal pinacoidpinacoid (c),(c), a firstfirst-or- or IIII.. SignificantSignificant angleangless ooff opticaopticall uniaxialuniaxial mineralsminerals second-ordersecond-order hexagonahexagonall prisprismm (m(m oorr a) andand anyany InIn orderorder toto understanunderstandd thethe introducedintroduced methodsmethods givengiven hexagonalhexagonal dipyramidipyramidd oorr rhombohedrorhombohedronn if(for or forfor thethe measuremenmeasurementt ooff significantsignificant anglesangles usefuluseful forfor ththee determinatiodeterminationn ofof growtgrowthh structuresstructures andand twintwin ninningg inin thethe threethree importantimportant gegemm mineralmineralss coruncorun f dum,dum, beryberyll andand quartzquartz,, whicwhichh araree useusedd aass examplesexamples r, forfor opticallopticallyy uniaxialuniaxial crystalscrystals,, iitt iiss necessarynecessary toto givegive 1 •• \ somesome basibasicc explanationsexplanations aboutabout crystalcrystal facefacess andand significantsignificant anglesangles usedused inin thithiss publication.publication. ^ / AlAlll crystalcrystalss ooff ththee aboveabove mentionementionedd threethree mineralmineral >. / species show hexagonal or trigonal symmetry, their species show hexagonal or trigonal symmetry, their I morphologmorphologyy mainlmainlyy consistconsistss ofof prism,prism, rhomborhombo- 1 .... I hedralhedral anandd pyramidapyramidall faces.faces. InIn additionaddition toto thesethese .... "----1 crystalcrystal faces,faces, thethe mineralsminerals corunducorundumm anandd berylberyl \f / ,(^{Y~< Y I .... 1 normallynormally revealreveal ththee basalbasal pinacoipinacoidd asas a characteristiccharacteristic \2/ "'JxJ morphologicamorphologicall feature.feature. ThThee basibasicc habithabit ooff thesethese threthreee mineralsminerals consistsconsists ooff a lowlow numbenumberr ooff signifisignifi Fig.Fig. I.1. StraightStraight growtgrowthh planeplaness thathatt forformm anan angle;/angle; fl,l5 andand/ f,2 cant,cant, recurrinrecurringg crystacrystall forms.forms. ThThee anglesangles formeformedd byby tracetracess ofof growtgrowthh planesplanes,, 4>

angle' angl e oneone crystalcrystal facfacee andand thethe c-axic-axiss aass wellwell aass ththee anglesangles mademade bbyy ththee twtwoo faces.faces. JJ.. Gemm.Gemm.,, 1991,22,61991,22,6 343477

I opticoptic axis

forforf f' basal pinacoidpinacoid hexagonal cc(000V (0001) r-----,------~------dipyramid or or A j rhorrboherhombohe- A-j J dron dron / /^\XAi fAc I / ) iI / 1 Ii I/ I I/ Jr fAm:' or \fAm\ or f'll a I / — f'Aa\I i i / 1 '/1hexagonalhi ?xagonal prism prism rrm(10TO)1(1010) or or a (1120) Fig.Fig. 2.2. Cross-sectionCross-section throughthrough a hexagonalhexagonal oror trigonaltrigonal crystalcrystal showingshowing thethe determinationdetermination ofof internainternall structuralstructural featuresfeatures byby useuse ofof thethe rotationrotation angleangle I'l,6, whichwhich isis formeformedd bbyy thethe opticoptic axisaxis ofof thethe uniaxiauniaxiall crystalcrystal andand anyany rhombohedralrhombohedral oror dipyramidaldipyramidal growthgrowth planeplane (j(f oror /')f');; furtherfurther characteristiccharacteristic anglesangles areare formedformed byby thethe basabasall pinacoipinacoidd (e)(c) oror a hexagonalhexagonal prisprismm faceface (m(m oror a) withwith ananyy rhombohedralrhombohedral oror dipyramidaldipyramidal growthgrowth planplanee (j(forf). or f'). ViewView perpendiculaperpendicularr toto thethe e-axis.c-axis.

1')./'). TheThe angleangle formedformed bbyy oneone ofof thethe crystalcrystal facesfaces bohedralbohedral oror dipyramidaldipyramidal faces,faces, e.g.e.g. thethe anglesangles withwith thethe opticoptic axisaxis isis designateddesignated O.6. ThisThis angleangle betweenbetween twotwo rhombohedralrhombohedral facesfaces randr and r'r' {lOTI}{1011} iinn indicatesindicates hohoww muchmuch thethe crystalcrystal hashas toto bebe tiltetiltedd awayaway corundum.corundum. fromfrom thethe opticoptic axiaxiss inin ordeorderr toto bebe ableable toto observeobserve thethe InIn TablesTables 1,1, 2 anandd 3 thethe mosmostt significantsignificant crystalcrystal tracetrace ofof thethe crystalcrystal faceface clearlyclearly inin thethe microscope.microscope. BByy facesfaces areare listedlisted whichwhich occuroccur inin naturalnatural andand syntheticsynthetic measuringmeasuring thisthis rotationrotation angleangle 0,6, itit isis easyeasy ttoo corundum,corundum, berylberyl andand quartz.quartz. InIn addition,addition, thethe anglesangles determinedetermine thethe correspondingcorresponding crystalcrystal faceface bbyy usingusing formedformed bbyy thethe correspondingcorresponding crystalcrystal facesfaces witwithh ththee TablesTables 1,21,2 oror 33,, respectively.respectively. c-axisc-axis (o-angles)(6-angles) andand thethe mostmost importantimportant anglesangles TheThe differentdifferent rhombohedralrhombohedral oror dipyramidaldipyramidal cryscrys formedformed bbyy twotwo crystalcrystal facesfaces areare given.given. InIn FiguresFigures 33,, taltal facesfaces if{/or/' or 1')) formform characteristiccharacteristic anglesangles withwith thethe 4 andand 5 somesome idealizedidealized lineline drawingsdrawings ofof thethe relevantrelevant basabasall planeplane (c)(c) oror withwith prismprism facesfaces (m(m oror a),a), whichwhich mineralsminerals withwith allall importantimportant crystalcrystal facesfaces ofof diagnosdiagnos alsoalso cancan bebe easilyeasily observeobservedd inin thethe microscope.microscope. IInn tictic valuevalue areare picturepicturedd revealingrevealing ththee relativerelative orientaorienta dependencedependence ofof 06 [cf.[cf. FigureFigure 2]2] therethere areare fourfour tiontion ofof thesethese facesfaces inin thethe crystals.crystals. importantimportant formulaeformulae indicatingindicating thethe relationrelation betweenbetween thethe angleangle formedformed bbyy anyany givengiven crystalcrystal faceface (j(/or/' or 1')) III.III. MeansMeans forfor thethe determinationdetermination ofof crystalcrystal facesfaces andand prismprism facesfaces (m(m oror a) oror betweenbetween thethe angleangle andand characteristiccharacteristic anglesangles formedformed bbyy anyany givengiven crystalcrystal facfacee (j(forf) or 1') andand thethe 777.III.]1 Sample holder with with twotwo rotationrotation axes axes and and its its use use basalbasal pinacoipinacoidd (c)(c):: InIn orderorder toto investigateinvestigate andand determinedetermine diagnosticdiagnostic structuralstructural propertiesproperties inin a facetedfaceted gemstonegemstone iinn 0 f/ /\A m = 180° - 60 differentdifferent directionsdirections ofof view,view, itit isis oftenoften necessarynecessary ttoo 0 I'/' A/\ a = 180° - 60 examineexamine a givengiven facetedfaceted samplesample inin differentdifferent orientaorienta f/ /\c=90A c = 90°0 +0+ 6 tions,tions, i.e.i.e. toto removeremove thethe samplesample fromfrom thethe holderholder andand I'/' /\c=90A c = 90°0 +0+ 6 ttoo placplacee thethe objectobject underunder investigationinvestigation afterafter ititss rotationrotation backback intointo thethe holderholder again.again. AccordinAccordingg ttoo BesidesBesides thethe aboveabove mentionementionedd anglesangles thertheree existexist thethe geometricalgeometrical propertiepropertiess ofof thethe cutcut gemstone,gemstone, somesome otherother importantimportant anglesangles formeformedd byby rhom-rhom distinctdistinct directionsdirections ofof viewview inin connectionconnection withwith ththee N 'oJ:) 'oJ:) 0- (D Cl - - J'-' ~ 00 ':-' ~ 34w 8 J. Gemm., 1991,22,6 f c-axis c) crystal, clinographic e) synthetic a crystal, natural flux-grown a a of of projection c-axislprojection b) clinographic d) e crystal, plane, natural a of composition as n) projection (1120) c-axis a a) crystal. with n (1010) flux-grown corundum; a of across GJCan~ synthetic projection contacttwin flux-grown crystal, and d clinographic f) natural synthetic of crystal, habit natural flux-grown a a of of characteristic projection projection The 3. Fig. J.J. Gemm.Gemm.,, 1991,22,61991, 22, 6 349349

m m m

Fig.Fig. 4.4. ThThee characteristicharacteristicc habihabitt ooff naturalnatural berylberyl;; aa)) c-axisc-axis projectionprojection,, b),b), c)c) clinographicclinographic projections.projections.

ordinarordinaryy 360°360° rotationrotation aboutabout ththee verticaverticall axisaxis ooff thethe conventionalconventional samplsamplee holderholder araree easileasilyy accomaccom plishedplished.. IInn otherother words,words, a cucutt gemstongemstonee iiss easilyeasily placeplacedd inin distinctdistinct orientationsorientations intintoo thethe conventionalconventional samplesample holdeholderr withwith oneone singlesingle verticalvertical rotatiorotationn axisaxis,, \ z / \ e.ge.g.. ththee gegemm isis heldheld bbyy thethe crocodilecrocodile clipsclips betweenbetween ththee tabletable andand culetculet oror aatt ththee girdlegirdle.. However,However, r Y r additionaadditionall andand differentdifferent orientationorientationss ooff a cutcut gemgem- stonestone araree mormoree difficuldifficultt toto obtain.obtain. BecausBecausee ofof thisthis factfact,, iitt isis veryvery timtimee consuminconsumingg oror sometimessometimes eveevenn impossiblimpossiblee toto adjusadjustt thethe optiopticc axisaxis z ofof a normallynormally facetedfaceted gemstongemstonee parallelparallel ttoo thethe / r \ 2- microscopmicroscopee axisaxis.. TheThe recognitionrecognition ofof structuralstructural propertiesproperties,, e.g.e.g. ththee exactexact determinatiodeterminationn ofof growthgrowth planeplaness usingusing thethe rotationrotation angleangle 0,6, anandd thethe verificaverifica tiotionn ooff thethe applicabilityapplicability ooff growthgrowth featuresfeatures foforr thethe a distinctiodistinctionn betweebetweenn naturalnatural andand syntheticsynthetic gemgem- stonesstones isis practicallpracticallyy impossiblimpossiblee oorr aatt leasleastt veryvery timetime consumingconsuming withwith thethe conventionallconventionallyy useusedd gegemm holhol ders.ders. FoForr thithiss reasonreason,, oneone ofof ththee authorauthorss (Schmetzer,(Schmetzer, 1985,1985, 1986)1986) improvedimproved thethe conventionalconventional samplesample holdeholderr witwithh ththee generallygenerally availableavailable 360°360° verticalvertical r rotatiorotationn axiaxiss bbyy addingadding a secondsecond horizontahorizontall rotationrotation axis.axis. BByy ususee ofof thisthis newnew axiaxiss a rotatiorotationn ofof thethe samplesample AA aboutabout ththee horizontahorizontall axiaxiss througthroughh anan anglanglee upup toto abouaboutt ± 40°40° isis practicable.practicable. ByBy attachingattaching a dialdial withwith a 0 360° subdivisiosubdivisionn ttoo ththee conventionaconventionall verticaverticall axiaxiss m hm andand addingadding a smallsmall indicatorindicator witwithh setset screwscrew ttoo thethe m 360°0 dial,dial, ththee anglanglee betweebetweenn twtwoo structuralstructural propprop ertieserties ofof a gemstone,gemstone, e.e.g g.. thethe angleangle betweenbetween thethe opticoptic axiaxiss ooff aann opticallopticallyy uniaxiauniaxiall mineraminerall anandd a distinctdistinct growtgrowthh oror twintwin planplanee cancan bbee measuredmeasured easileasilyy [cf.[cf. \ ) FigurFiguree 2]2].. \ TheThe measuremenmeasurementt ooff structuralstructural elementselements isis carcar / b riedried ououtt aass followsfollows:: bbyy usinusingg crossecrossedd polarizerpolarizerss inin ^ ththee gemgem microscope,microscope, interferencinterferencee figures consistingconsisting ooff colourecolouredd interferenceinterference ringringss areare observeobservedd inin distincdistinctt orientationorientationss ofof thethe crystal.crystal. TiltingTilting thethe crystacrystall towardtowardss a positiopositionn inin whicwhichh ththee anglanglee FigFig.> 55.. ThThee characteristicharacteristicc habihabitt ooff naturanaturall quartzquartz;; aa)) oaxic-axiss betweebetweenn thethe Optiopticc axiaxiss ooff thethe sampleSample anandd ththee projectionprojection,, bb)) clinographicclinographic projection.projection. 350 J. Gemm., 1991, 22, 6

Fig. 9. Angled growth structure in natural sapphire from Pailin, Cambodia; planes parallel to the hexagonal dipyramids z and z' (2241) form an angle of 121.1°. View 10.4° inclined to the c-axis, crossed polarizers, 20x. microscope axis is diminished, the interference rings move towards the centre of the stone [Figures 6, 7]. After having placed the optic axis in the best available position [Figure 8], the indicator attached to the, dial of the vertical axis is fixed to 0°. Afterwards, the sample is rotated about the vertical axis towards a position, in which sharp parallel growth planes or a single twin plane become visible in the gem microscope [Figure 9]. By use of a rotation angle 6, which is now directly readable on the dial, the growth or twin plane under investiga tion is exactly determined [cf. Tables 1, 2 and 3]. The experimental limit of error in the measurement of 6 with the method described equals ± 1°. Consequently, all crystal faces quoted in Tables 1,2 and 3 are unequivocally determined with the excep tion of v (4481) and co (14 14 28 3) in corundum with 6-values of 5.2 and 4.5°, respectively. For a more detailed description of this sample holder with two rotation axes and its use for the distinction of natural and synthetic ruby as well as natural and synthetic amethyst consult the paper of Schmetzer (1986) in this journal. A further improvement of the sample holder described above is the use of three independent rotation axes and three attached dials. This type of sample holder [Figure 12] allows the conventional 360° rotation about the vertical axis, and additional rotations about two horizontal axes, which are orientated parallel and perpendicular to the micro scope axis, through angles up to about ± 40° in both Figs. This series describes the variation of interference directions. This three-axial sample holder can be 6, 7, 8. figures of a natural ruby from Burma during a slight used like that one with two rotation axes, but it is rotation of the stone; Fig. 6: the angle between the optic axis and the microscope axis is about 35°; Fig 7: also possible to use all three axes with attached dials tilting the corundum crystal slowly towards a position, for the determination of crystal faces by means of in which the angle between the optic axis and the the stereographic projection. However, this proce microscope axis is diminished moves the interference dure needs more experience and is quite compli rings towards the centre; Fig. 8: the optic axis is exactly parallel to the microscope axis. Crossed polar cated. Therefore, this method will not be discussed izers, 60 x. in further detail within this publication. The three- J. Gemm., 1991,22,6 351

Figs. This series describes the determination of an angle 4>' formed by two families of straight parallel growth planes in a natural 10, 11. emerald from Nigeria; Fig. 10: one wire of the cross hairs attached to the objective lens is tilted towards a position exactly parallel to the first group of parallel growth planes [in this case growth planes parallel to the basal pinacoid c (0001)], the dial attached to the objective tube is adjusted with its Opposition coincident with the indicator fixed to the ocular; Fig. 11: the objective with fixed indicator is tilted into a position, in which the wire of the cross hairs is exactly parallel to the second group of parallel growth planes [in this case growth planes parallel to the hexagonal dipyramidp (1012)], the angle formed by the two sets of growth planes [in this case 150.1°] is now directly readable on the 360° dial. - View perpendicular to the c-axis, the c-axis runs almost horizontally, crossed polarizers, 20 x. axial type of sample holder is especially applicable 360° dial attached to the ocular tube. In general, for optical biaxial gem minerals, e.g. for the distinc both crystal faces under investigation are determin tion of natural and synthetic alexandrite. able by the use of Tables 1,2 or 3, respectively.

III.2 Measuring ocular and its use In situations when the optic axis is not easily orientated parallel to the microscope axis or for a direct determination of two families of straight parallel growth planes, it is often useful to work with a measuring ocular in addition to one of the above described sample holders. The measuring ocular consists of the normal rotary eyepiece of the gem microscope with cross hairs attached to the ocular lens. Attached to the eyepiece tube there is a fixable 360° dial, and connected to the ocular there is a fixed indicator. With these supplementary facilities attached to the conventionally available eyepiece, it is possible to measure easily the angle 4> formed by two structural features, e.g. between two families of straight parallel growth planes, which reflect the morpho logy of a rough crystal [Figures 9,10 and 11]. Using the above mentioned facilities, first the trace of two families of straight parallel growth planes have to be observable in the microscope. By rotating the eyepiece with the cross hairs, the ocular is placed in a position with one wire of the cross hairs parallel to the first family of growth planes [Figure 10]. Subsequently, the dial attached to the objective tube is rotated and adjusted with its Opposition coincident with the indicator, which is fixed to the ocular. The ocular is now turned into a position, in which the direction of the second family of parallel growth planes coincides with the wire of the eyepiece [Figure 11]. The angle between the two Fig. 12. Improved three-axial sample holder with one 360° sets of growth planes is now directly readable at the vertical and two ±40° horizontal rotation axes, each of position of the indicator fixed to the objective at the them having an attached dial. 352352 J.J. Gemm.Gemm.,, 1991,22,61991, 22, 6

FigFig.. 13.13. Cross-sectionsCross-sections ofof a facetedfaceted opticallyoptically uniaxiauniaxiall gemstonegemstone (natura(naturall emeraldemerald)) inin differentdifferent orientationsorientations withwith thethe optiopticc axisaxis parallelparallel toto ththee microscopmicroscopee axiaxiss (cross-section(cross-sectionss (a),(a), (b(b)) anandd (c(c)) araree relaterelatedd bbyy a rotationrotation ofof 45°45° abouaboutt thethe optiopticc axis);axis); rotatingrotating thethe crystalcrystal abouaboUlt ththee 360°360° verticaverticall rotationrotation axisaxis,, inin eacheach ooff thethe differentdifferent orientationorientationss (a)(a),, (b)(b) anandd (c)(c) ththee tracetracess ofof variousvarious setsetss ofof parallelparallel growtgrowthh planeplaness becombecomee visiblvisiblee iinn ththee microscopemicroscope anandd araree determinedeterminedd byby useuse ooff thethe rotatiorotationn anglanglee D.6.

III.III.3 3 Suggested combinationcombination of of both both methods methods ForFor a combinatiocombinationn ofof botbothh methodmethodss describedescribedd inin sectionssections 111.1III. 1 andand 111.2,III.2, a firstfirst generalgeneral stepstep wouldwould bbee ththee determinationdetermination ofof thethe positiopositionn ooff thethe opticoptic axiaxiss ofof ththee facetefacetedd gemstongemstonee underunder investigationinvestigation asas explaineexplainedd iinn sectionsection 111.1.III. 1. ForFor subsequentsubsequent proceproce dures,dures, itit isis helpfuhelpfull ttoo retairetainn thethe orientationorientation ofof thethe optiopticc axiaxiss relativerelative ttoo ththee girdlgirdlee oror relativrelativee toto dominantdominant facetsfacets,, e.ge.g.. ththee tabletable facetfacet ofof thethe cutcut gemstone,gemstone, andand alsalsoo relativrelativee toto distinctdistinct typetypess ooff inclusioninclusionss ifif presentpresent.. NoNoww parpartt ooff ththee internalinternal crystalcrystal facesfaces cacann bebe.. determinedeterminedd accordinaccordingg toto secsec tiontion 111.1III. 1 byby rotationrotation ofof thethe gemstonegemstone aboutabout thethe verticalvertical axiaxiss anandd measurinmeasuringg thethe rotatiorotationn angleangle b6 betweebetweenn appearinappearingg straightstraight paralleparallell growthgrowth planesplanes a anandd thethe opticoptic axisaxis.. TToo obtaiobtainn a maximumaximumm numbenumberr ooff crystalcrystal facesfaces byby thithiss methodmethod,, thethe stonestone itselfitself shouldshould bbee placeplacedd inin differendifferentt orientationorientationss intointo thethe samplesample holder,holder, whicwhichh araree relatedrelated bbyy a rotationrotation ofof 45°45° aboutabout thethe opticoptic axiaxiss asas shownshown iinn FigureFigure 13,13, keepinkeepingg ththee opticoptic axiaxiss paralleparallell toto thethe microscopemicroscope axisaxis iinn alalll differentdifferent orientations.orientations. ThisThis procedurproceduree iiss necessarnecessaryy becausebecause inin ononee simplesimple orientation,orientation, onlonlyy parpartt ofof alalll growthgrowth planeplaness ofof thethe gemstonegemstone becombecomee visiblvisiblee throughthrough a 360°360° rotatiorotationn ofof thethe samplesample abouaboutt thethe verticaverticall axisaxis ooff thethe samplesample holder.holder. InIn a secondsecond step,step, thethe gemstongemstonee shouldshould bbee rotatedrotated througthroughh 9090°° towardtowardss anan orientationorientation,, inin whichwhich thethe optiopticc axisaxis ofof thethe gemstongemstonee isis placeplacedd iinn a directiondirection b paralleparallell ttoo thethe 360360°° verticaverticall axiaxiss ooff ththee samplesample holdeholderr [Figure[Figure 14].14]. InIn thathatt particulaparticularr orientation,orientation, lugPig.. 14.14. Cross-sectionsCross-sections ooff a facetedfaceted opticaopticall uniaxiauniaxiall gemstonegemstone thethe growthgrowth structuresstructures paralleparallell ttoo ththee basabasall pinacoidpinacoid (natura(naturall emerald)emerald) iinn differendifferentt orientationorientationss witwithh thethe (c)(c) or parallel to the first- or second-order hexagon opticoptic axisaxis paralleparallell ttoo thethe 3603600° verticaverticall rotatiorotationn axisaxis or parallel to the first- or second-order hexagon (cross-section(cross-sectionss (a(a)) anandd (b)(b) areare relatedrelated bbyy a rotationrotation ooff alal prisprismm facefacess (m(m oror a) cancan bebe recognizerecognizedd easilyeasily.. 3030°° abouaboutt thethe optiopticc axis)axis);; bbyy a rotatiorotationn througthroughh 3030°° DurinDuringg a rotationrotation ooff ththee gemstongemstonee aboutabout ththee 360°360° aboUlabout thethe 360360°° verticalvertical rotationrotation axiaxiss (i.e(i.e.. iinn thisthis verticalvertical axiaxiss ooff thethe samplesample holder,holder, thethe basabasall pinapina particular orientation about the optic axis), various particular orientation aboUl the optic axis), various coid (c)(c) or growth structures parallel to this face are setsetss ooff growthgrowth planesplanes becombecomee visible;visible; bbyy a rotationrotation coid or growth structures parallel to this face are througthroughh 60°60°,, identicaidenticall setssets ooff growtgrowthh planeplaness araree reperepe permanentlpermanentlyy visiblvisiblee iinn thethe gemgem microscopmicroscopee [Fi[Fi atedated.. guresgures 14,14, 15].15]. AfterAfter eaceachh 3030°° oror 60°60° rotation,rotation, J.J. Gemm.,Gemm., 1991,22,61991, 22,6 353353

c \ c ~\\/ \ z z\z I \ t I I I I I I I I I I a a I I I I I , \r} z z \.~\ __c__ ...1/ c \ '/ k J I a II

c r\ c n n\n d > / /- f r \ n n

I b II

c c fiP < A5 5 s m m a a

I c II

'rr z\z

\mm m

\Zz rr/

Fig.Fig. IS.15. Cross·sectionsCross-sections ofof naturalnatural corundumcorundum (a),(a), syntheticsynthetic flux-grownflux-grown corundumcorundum (b),(b), naturalnatural berylberyl (c),(c), andand naturalnatural quartzquartz (d);(d); solidsolid lineslines representrepresent tracestraces ofof crystalcrystal faces,faces, dasheddashed lineslines representrepresent edgesedges ofof thethe crystals;crystals; (a),(a), (b),(b), andand (c):(c): byby a rotationrotation throughthrough 30030° aboutabout theirtheir opticoptic axis,axis, cross-sectionscross-sections (I)(I) ofof thethe opticaloptical uniaxialuniaxial crystalscrystals areare convertedconverted toto crosscross sectionssections (II);(II); byby a rotationrotation throughthrough 60'60° aboUlabout thethe opticoptic axisaxis cross-sectionscross-sections (I)(I) ooff thethe opticallyoptically uniaxialuniaxial crystalscrystals areare convertedconverted ttoo cross-sectionscross-sections (I')(I') withwith identicalidentical facesfaces oror cross-sectionscross-sections (II)(II) areare convertedconverted toto cross-sectionscross-sections (II')(II') withwith identicalidentical faces,faces, respectively;respectively; (d):(d): bbyy a rotationrotation throughthrough 60'60° aboutabout thethe opticoptic axisaxis identicalidentical cross-sectioncross-sectionss areare repeated.repeated. - ViewView perpendiculaperpendicularr toto thethe Coaxes,c-axes, thethe coaxesc-axes runrun vertically.vertically. 353544 JJ.. Gemm.Gemm.,, 19911991,22,6, 22, 6 subsequensubsequentt firstfirst-- and/oand/orr second-ordesecond-orderr prisprismm facefacess verticaverticall axiaxiss ooff ththee samplsamplee holdeholderr anandd measuremenmeasurementt becombecomee visiblvisiblee (i(iff presenpresentt iinn ththee samplsamplee undeunderr ooff ththee rotatiorotationn anglanglee ob,, thithiss procedurproceduree iiss aatt leasleastt investigation)investigation).. Afte Afterr measurinmeasuringg ththee angleangless 'r/> I twictwicee repeaterepeatedd iinn differendifferentt orientationorientationss ooff ththee formeformedd bbyy aann unknowunknownn crystacrystall facfacee (f(j oorr f)1') witwithh gemstonegemstone,, whicwhichh araree relaterelatedd bbyy a rotatiorotationn ooff 4545°° ththee basabasall pinacoipinacoidd (c(c)) oorr witwithh prisprismm facefacess ((mm oorr a; abouaboutt ththee optiopticc axisaxis.. cfcf.. FigurFiguree 22)) usinusingg ththee methomethodd describedescribedd iinn sectiosectionn A seconsecondd neneww methomethodd foforr ththee determinatiodeterminationn ooff IIIIII.2,. 2, botbothh angleangless cacann bbee useusedd foforr ththee determinadetermina crystacrystall facefacess ooff opticaopticall uniaxiauniaxiall mineralmineralss useusedd bbyy tiotionn ooff ththee unknowunknownn growtgrowthh planeplaness (cf(cf.. TableTabless 11,2, 2 ththee authorauthorss iiss ththee measuremenmeasurementt ooff characteristiccharacteristic anandd 3)3).. angleangless betweebetweenn twtwoo crystacrystall facefacess bbyy usinusingg croscrosss AfteAfterr ththee exacexactt determinatiodeterminationn ooff ononee grougroupp ooff hairhairss iinn a measurinmeasuringg oculaocularr anandd a 360360°° dial attachedattached growtgrowthh planeplaness iiss performeperformedd iinn ononee distincdistinctt orientaorienta ttoo ththee tubtubee ooff ththee eyepieceeyepiece.. IInn ordeorderr ttoo performperform tiotionn ooff ththee samplesample,, subsequentlsubsequentlyy rotatinrotatingg ththee hexhex thesthesee subsequensubsequentt serieseriess ooff measurementsmeasurements,, ththee agonaagonall oorr trigonatrigonall gemstongemstonee abouaboutt ititss verticallverticallyy stonstonee iiss removeremovedd frofromm ththee samplsamplee holdeholderr anandd placeplacedd optiopticc axisaxis,, afteafterr eaceachh rotatiorotationn througthroughh 30°30°,, reorientatereorientatedd iinn a positionposition,, iinn whicwhichh ththee optiopticc axiaxiss iiss successivelsuccessivelyy ththee nexnextt sesett ooff growtgrowthh planeplaness witwithh perpendiculaperpendicularr ttoo ththee microscopmicroscopee axisaxis.. ThiThiss meanmeanss differendifferentt 'r/> I angles angle sshould shoul dappear appea rfor fo rcorundum corundu m ththee optiopticc axiaxiss iiss nonoww paralleparallell ttoo ththee verticaverticall 360360°° anandd beryberyll [Figure[Figuress 1414,, 15]15].. HoweverHowever,, ththee angleangless rotatiorotationn axiaxiss ooff ththee samplsamplee holderholder,, whicwhichh allowallowss a betweebetweenn ththee growtgrowthh planeplaness (f(j oorr 1')/') anandd ththee basabasall rotatiorotationn 'ofof ththee facetefacetedd gemstongemstonee undeunderr maintemainte pinacoipinacoidd (c(c)) oorr ononee ooff ththee prisprismm facefacess (m oorr a) araree nancnancee ooff ththee positiopositionn ooff ththee optiopticc axisaxis.. ThThee structustructu repeaterepeatedd afteafterr eaceachh rotatiorotationn througthroughh 6060°° foforr alalll rarall featurefeaturess araree thethenn determinabldeterminablee bbyy measuringmeasuring threthreee mineralsminerals,, corundumcorundum,, beryberyll anandd quartquartzz [Fi[Fi ththee angleangless betweebetweenn knowknownn crystacrystall facefacess thathatt appearappear gurguree 15].15]. IInn generalgeneral,, witwithh severaseverall subsequensubsequentt rotarota frequentlyfrequently,, liklikee ththee basabasall pinacoiplnacoidd (c(c)) oorr ononee ooff thethe tiontionss ooff ththee crystacrystall abouaboutt ththee optiopticc axiaxiss througthroughh 3030°° hexagonahexagonall prispfismm facefacess ((mm oorr a), anandd aann unknownunknown eacheach,, a completcompletee sesett ooff growtgrowthh structurestructuress becomesbecomes crystacrystall facfacee (f(j oorr 1')./')• WitWithh ththee samsamee methomethodd a visiblvisiblee iinn ththee gegemm microscopmicroscopee anandd ththee determinadetermina determinatiodeterminationn ooff twitwinn oorr glidglidee planeplaness iiss possiblepossible.. tiotionn ooff alalll structurastructurall propertiepropertiess ooff ththee mineraminerall iiss FurthermoreFurthermore,, ththee angleangless betweebetweenn adjacenadjacentt rhomrhom- performableperformable.. bohedrabohedrall oorr pyramidapyramidall facefacess araree ablablee ttoo bbee deterdeter minedmined.. IVIV.. ConclusionsConclusions WitWithh somsomee experienceexperience,, ththee combinatiocombinationn ooff bothboth IInn thithiss firsfirstt parpartt ooff ththee articlarticlee a generagenerall survesurveyy ooff methodmethodss allowallowss ththee completcompletee determinatiodeterminationn ooff alalll differendifferentt possibilitiepossibilitiess foforr ththee determinatiodeterminationn ooff existinexistingg growtgrowthh structurestructuress aass welwelll aass twitwinn oorr glideglide structuralstructural featurefeaturess ooff facetefacetedd uniaxiauniaxiall gemstonesgemstones planeplaness ooff everyevery opticallyoptically uniaxialuniaxial mineral.mineral. byby useuse ofof a samplesample holdeholderr withwith twotwo independentindependent InIn thethe secondsecond anandd thirthirdd parpartt ooff thisthis publication,publication, rotatiorotationn axesaxes iiss givengiven.. TheThe basibasicc purpospurposee foforr thethe whichwhich willwill appeaappearr inin subsequentsubsequent issueissuess ooff thisthis additioadditionn ooff a secondsecond horizontahorizontall rotationrotation axisaxis isis anan journaljournal,, somesome examplesexamples forfor thethe applicatioapplicationn ofof thethe easyeasy orientationorientation ooff ththee opticoptic axisaxis ofof ththee gemgem parallelparallel methodsmethods describedescribedd foforr thethe characterizatiocharacterizationn ofof imim ttoo thethe microscopmicroscopee axis.axis. WithWith anan additionaadditionall imim portanportantt gemgem mineralsminerals ooff distincdistinctt occurrenceoccurrencess aass provemenprovementt ofof thethe two-axialtwo-axial samplesample holderholder towardstowards welwelll aass somesome commocommonn syntheticsynthetic gemstonesgemstones availavail a three-axialthree-axial one,one, itit isis alsoalso possiblepossible toto determinedetermine ablablee iinn ththee tradtradee areare describeddescribed iinn detail.detail. characteristiccharacteristic crystalcrystal facesfaces anandd anglesangles ofof opticallyoptically biaxialbiaxial minerals,minerals, e.g.e.g. alexandrite.alexandrite. FoForr thisthis somesome ReferenceReferencess whawhatt moremore complicatedcomplicated methomethodd ththee ususee ofof thethe Klein,Klein, C.C.,, HurlbutHurlbut,, C.S.,C.S., Jr.,Jr., 1985.1985. Manual of Mineralogy (afler(after stereographic projection is necessary. James D. DanaDana),), TwentiethTwentieth Edition.Edition. JohJohnn WileyWiley & Sons,Sons, stereographic projection is necessary. NeNeww York.York. InIn a firstfirst step,step, itit isis importantimportant toto locatelocate thethe opticoptic Schmetzer,Schmetzer, K.,K., 1985.1985. EinEin verbesserterverbesserter ProbenhalterProbenhalter undund seineseine axisaxis ofof thethe stonestone underunder investigationinvestigation relativerelative toto thethe AnwendungAnwendung aufauf ProblemeProbleme derder UnterscheidungUnterscheidung natiirlichernatürlicher dominantdominant facetsfacets ofof thethe stone.stone. WithWith thethe opticoptic axisaxis und synthetischersynthetischer Rubine Rubine sowie sowie natürlicher natiirlicher und synthetischer und syntheti Amethyste.scher Amethyste. Z. Dt. Gemmol. Z. Dl. Ges. Gemmol., 34, 30-47. Ges., 34, 30-47. orientatedorientated parallelparallel toto thethe microscopemicroscope axis,axis, itit isis Schmetzer,Schmetzer, K.,K., 1986.1986. AnAn improvedimproved samplesample holderholder andand itsits useuse inin possiblepossible toto determinedetermine thethe rotationrotation anglesangles b6 ooff thethe distinctiondistinction ofof naturalnatural andand syntheticsynthetic rubyruby asas wellwell asas growthgrowth planesplanes byby tiltingtilting thethe gemstonegemstone inin a direcdirec naturalnatural andand syntheticsynthetic amethyst.amethyst. J. Gemm.,Gemm., 20,20, 20-33.20-33. tion,tion, inin whichwhich thethe opticoptic axisaxis isis horizontallyhorizontally twistedtwisted [Manuscript[Manuscript receivedreceived 3 3 May May 1989.]1989. ] towardstowards anan orientationorientation perpendicularperpendicular toto thethe micromicro scopescope axis.axis. TheThe angleangle b6 betweenbetween thethe opticoptic axisaxis andand a familyfamily ofof straightstraight parallelparallel growthgrowth planesplanes isis readread ableable atat thethe dialdial fixedfixed toto thethe 360°360° verticalvertical axisaxis ofof thethe samplesample holder.holder. HavingHaving performedperformed thethe alignmentalignment ofof thethe opticoptic axisaxis andand thethe determinationdetermination ofof growthgrowth structuresstructures byby rotationrotation ofof thethe samplesample aboutabout thethe J.J. Gemm.,Gemm., 1991,22,61991, 22, 6 355355

EmeraldEmeraldss fromfrom ColombiaColombia (Part(Part 1)*1)* George Bosshart Bosshart Switzerland Switzerland

AbstracAbstractt beryberyll latticlatticee (C(Crr = V,V, witwithh thethe Cr/CrNV ratiratioo foundfound ttoo bebe IntroductioIntroductionn (Par(Partt 1I)) ranginrangingg fromfrom 4.4.55 ttoo 0.50.5,, iinn extremextremee casecasess frofromm aboutabout 1100 AlAI.. TheThe historyhistory ooff ththee ColombiaColombiann emeralemeraldd minesmines ttoo 0.1)0.1).. IronIron,, howeverhowever,, hahass barelybarely beebeenn detecteddetected iinn thethe A2A2.. TheThe geographicalgeographical locatiolocationn ofof thethe emeraldemerald UV/VIUV/VISS absorptioabsorptionn spectraspectra ooff ColombiaColombiann emeralds.emeralds. occurrenceoccurrencess ThoughThough generallgenerallyy presentpresent inin slightlyslightly largerlarger amountsamounts thathann Cr33++,, iroironn doedoess nonott recognizablyrecognizably influencinfluencee thethe 2+ 3+ colourcolour (littl(littlee Fe2 + anandd possiblypossibly somesome Fe3 + positionepositionedd inin BlB 1.. ThThee emeralemeraldd depositsdeposits andand theitheirr geologicalgeological ththee axiaaxiall channelschannels ooff ththee ring-silicatring-silicatee structure).structure). environmentenvironment A detailed presentation presentation of ofthe the currently currently known known internal inter B2B2.. HypotheseHypothesess ofof emeraldemerald genesisgenesis nal characteristiccharacteristicss (inclusion(inclusionss anandd growtgrowthh structures)structures) iiss B3.B3. ThThee minemine workingsworkings supplemented by by a discussion a discussion of identification of identification problems prob lems witwithh treatetreatedd emeraldsemeralds anandd ththee disclosuredisclosure ooff thethe GemmologicalGemmological propertiesproperties (Part(Part 2)2) treatmentreatmentt durinduringg transactionstransactions iinn thethe wholesalewholesale anandd retailretail CIC1.. Morphology,Morphology, qualityquality andand sizesize ooff ththee emeraldemerald trade. Allocation of the emeralds to individual Colombian crystalcrystalss Allocation of the emeralds to individual Colombian mineminess oonn ththee basibasiss ofof inclusioninclusion patternpatternss doedoess notnot appearappear C2C2.. ChemicalChemical composition,composition, chromophorchromophoree anandd tracetrace possiblpossiblee inin mosmostt instances.instances. However,However, thethe differentiationdifferentiation elementelement contentscontents ooff ColombiaColombiann emeraldsemeralds fromfrom otheotherr naturalnatural emeraldsemeralds C3.C3. LighLightt absorptionabsorption,, coloucolourr anandd fluorescencefluorescence (suc(suchh aass thosthosee frofromm ththee PanjshePanjsherr ValleValleyy exhibitingexhibiting veryvery C4C4.. OpticaOpticall valuevaluess andand densitydensity similarsimilar (s,l,g(s,l,g)) three-phasthree-phasee inclusionsinclusions)) oror frofromm difficult,difficult, C5CS.. InclusionInclusionss anandd growtgrowthh characteristicscharacteristics modermodernn hydrothermahydrothermall anandd flufluxx syntheticssynthetics iiss shownshown ttoo bebe feasiblfeasiblee bbyy a combinatiocombinationn ofof microscopy,microscopy, refractometry,refractometry, TreatmentTreatmentss (Part(Part 3)3) anandd absorptionabsorption spectrometryspectrometry (UVNIS(UV/VIS andand NIR/MIR),NIR/MIR), DD.. Oil,Oil, ultrasonicultrasonic anandd heaheatt treatmentstreatments assisteassistedd bbyy chemicalchemical analysisanalysis onlonlyy inin thethe mosmostt difficultdifficult casescases.. SafeSafe identificatioidentificationn ofof authenticityauthenticity,, treatment,treatment, andand originorigin ofof emeralds,emeralds, howeverhowever,, isis increasinglincreasinglyy becomingbecoming DiscussioDiscussionn ththee tasktask ofof thethe expertexpertss iinn thethe specializedspecialized laboratory.laboratory. EE.. DifferentiatioDifferentiationn ooff thethe ColombiaColombiann emeraldemeraldss fromfrom ThThee mineralogicamineralogicall definitiodefinitionn ooff emeralemeraldd aass a yellowishyellowish naturalnatural emeraldemeraldss ooff otheotherr origins,origins, syntheticsynthetic toto bluish-greenbluish-green varietvarietyy ooff naturanaturall beryberyll iiss shownshown ttoo bebe emeraldsemeralds andand emeralemeraldd imitationsimitations valid forfor any any Cr Cr and and V-containing V-containing variety variety except except possibly poss ibly thethe rare,rare, absolutelabsolutelyy chromium-frechromium-freee (V,Fe)-beryls(V,Fe)-beryls AcknowledgementsAcknowledgements (modification of of the the former former definition definition of type of typeII emerald): II emer BibliographBibliographyy ald): inin manmanyy ooff thethe preferredpreferred ColombianColombian emeralds,emeralds, chromiumchromium isis clearlyclearly dominateddominated bbyy vanadiumvanadium (CrN(Cr/V ratioratio AbstractAbstract < 1).1). However,However, chromiumchromium hashas a higherhigher efficiencyefficiency ofof A condensedcondensed historicahistoricall anandd mininminingg surveysurvey isis followedfollowed colorationcoloration thathann vanadiumvanadium andand a muchmuch highehigherr oneone thanthan by aa compilation compilation of ofthe themost most notable notable crystals crystals of Colombian of Col iroironn ionsions inin thethe variousvarious substitutionalsubstitutional anandd interstitialinterstitial ombian emeraldemeraldss eveeverr foundfound anandd ofof thethe detaildetailss ofof theirtheir latticlatticee sitessites ofof beryl.beryl. CrCr influencesinfluences colourcolour eveevenn aatt veryvery chemicalchemical composition.composition. A summarysummary ofof ththee elementalelemental low tracetrace levels.levels. substitutionssubstitutions andand theirtheir effectseffects oonn ththee outlinedoutlined rangrangee ooff AnAn extensivextensivee andand up-dateup-datedd selectionselection ofof literature,literature, gemmological data data is is given. given. coverincoveringg allall aspectsaspects citedcited,, completecompletess thethe synopsis.synopsis. SpecialSpecial emphasisemphasis iiss placeplacedd oonn ththee causecause ofof thethe famous,famous, vividlyvividly greegreenn colorationcoloration,, i.e.i.e. onon ththee selectiveselective absorptionabsorption ThThee introductiointroductionn toto thisthis revierevieww iiss basebasedd oonn thethe studystudy ooff a fractiofractionn ofof thethe extraordinarilextraordinarilyy extensiveextensive literaturliteraturee onon ColombianColombian emeralds.emeralds. of orange-redorange-red and and violet violet light, light, dictated dictated by minor by minor contents con ThThee maimainn partpart ofof thethe papepaperr (Part(Part 22)) containcontainss datadata collectedcollected anandd findingsfindings tentsof the of thechromophoric chromophoric elements elements Cr and Cr V andsubstituting V substitut achieveachievedd oveoverr manmanyy yearyearss iinn thethe SSESSEFF LaboratorLaboratoryy iinn Zurich.Zurich. ingfor for Al 3+A1 in3 +octahedrally in octahedrally coordinated coordinated sites of thesites of the ParPartt 3 willwill dealdeal withwith thethe difficultiedifficultiess encountereencounteredd iinn identifyingidentifying treatedtreated emeraldsemeralds anandd witwithh thethe disclosurdisclosuree necessarnecessaryy whenwhen sellingselling thethemm anandd willwill *Thi*Thiss isis a papepaperr whicwhichh wilwilll bbee publishepublishedd iinn The Journal iinn threthreee partsparts.. TheThe discussdiscuss ththee possibilitiespossibilities ooff differentiatiodifferentiationn betweenbetween ColombiaColombiann anandd otherother completecomplete bibliographbibliographyy iiss presentepresentedd witwithh ParPartt 11.. naturalnatural emeraldemeraldss anandd ththee synthetisyntheticc emeralds.emeralds.

Introduction coast 400 years ago. A ship of the Tierra Firme fleet, Al. The history of the Colombian emerald mines the galleon Nuestra Senora de Atocha for instance, The ancient South American Indian tribes were sank in 1622 near the Florida Keys, carrying rich in natural resources, yet their need of these valuable gold and emerald freight. In 1985, over goods was modest and sensible. Gold and emeralds 2300 loose and set emeralds were successfully lifted were used commercially as well as for royal insignia. off the wreck. The largest stones recovered weighed Both had a symbolic and ceremonial character. The 64 and 30 carats. original inhabitants of Peru, Mexico and the Carib bean were treated less kindly by fate than the A2. The geographical location of the emerald occurr Chinese, Japanese or other ancient cultures. From ences about 1500 onwards, the Incas, Aztecs and Mayans The Andes are mountain chains rich in raw were overrun, enslaved and exploited by the so- materials. Together with the Himalayas, the Alps called discoverers from the Old World. and the North American cordilleras, they belong to The emerald pits of the Chibcha Indios near the youngest and highest mountain systems in the Somondoco, later called Chivor, were discovered by world. All these Alpine type mountain ranges were the Spaniards in the early sixteenth century and and still are being thrust upward at the front of from then on intensely mined. The finds of the slowly drifting Continental plates (in the case Muzo Indians took the same course once the tribes discussed, at the front of the very old Brazilian and had been subjected by the Spaniards. In the the Guyana plates)1. seventeenth century, the decimation of the Col The results of plate movements and orogenies are ombian Indians through imported illnesses and frequent earthquakes and volcanic eruptions, such drudgery was such that it led to a shortage of cheap as the big quakes in North Yemen (1982), Mexico slave labour. Chivor was forced into oblivion for the City (1985), the San Francisco Bay (1989) or the next 200 years and the deposits were overgrown by Philippines (1990) and the eruptions of Mount St. jungle vegetation. Mining in Muzo became spor Helens (1980) or of the Nevado del Ruiz (1985), less adic. than 100 km north-west of Muzo. However, between 1537 and 1650 the Spanish From the south-west to the north-east, the Col royalty had accumulated such immense riches that ombian Andes divide into three mountain ranges, all purchasing wishes of the Indian Moguls, the the Cordillera Occidental, Central and Oriental. Ottoman aristocracy and the European courts could The connection with the North American cordiller be satisfied. Because of the scarcity of green woods as is established via both Central American bran and fields in their own countries, the Muslims have ches, the western chain running directly through treasured for ages the colour green. In fact it is the the west of Mexico, the eastern chain bending via holy colour of Islam. This explains the abundance Venezuela and the long Caribbean archipelago back of Colombian emeralds in the treasuries of Arabian to Yucatan and then northward towards the Rocky sheiks. The Persian crown jewels in particular are mountains. said to abound with these gems. Hundreds of Extending for some 150 km, the Colombian cabochons and faceted emeralds over 100 carats, emerald belt stretches from the north to the east of some even over 300 carats, were to be found in the the capital, Bogota, across the eastern branch of the safes of the Banque Markazi in Teheran. Andes. This Cordillera Oriental divides the belt Beautiful and large, rough and cut, engraved and into two mining districts2 with Muzo and Coscuez inscribed Colombian emeralds from that period can in the north-west (Boyaca Province), and Chivor also be admired in the Topkapi Palace Museum in (Boyaca and Cundinamarca R) and the mines of Istanbul. Gachala in the south-east (Cundinamarca Pro Notable historic crystal groups, single crystals vince). Even between neighbouring mines of the and Colombian emerald gems from colonial times Muzo district there is no very obvious geological are also exhibited in the Natural History Museum relationship. The rugged terrain and the thick in Vienna (among others the group of crystals ^he formation of the Colombian Andes is not due to simple or nappe named 'Moctezuma', measuring 17x16 cm and folding. They are marine and continental block formations generated by the horizontal north-west drift of the Guyana plate (presently at a rate of consisting of single Muzo and Chivor crystals glued about 50 mm per year) onto the subducted Pacific Nazca plate. Geological together). An original Chivor crystal group approx terms: orogeny = formation of mountains, subduction = down- movement (of marine plates), circum-Pacific mountain systems = Andes/ imately 30 cm across, carried by the figure of a Rocky Mountains/Aleutian island arch/Japan/Philippines/New Guinea/ Moor, and an emerald suite are displayed in the New Zealand Alps. Green Vaults of Dresden. Fine specimens are to be 2The mines of the Muzo district from south to north are: El Pehon, Aposentos (near Yacopi), Coper, Maripi, Muzo (Tequendama, Santa seen in many other museums (except in Spain where Barbara, El Chulo), Coscuez and Penas Blancas. Those of the Chivor royalty was said to have preferred gold to emeralds). district from S to N are: Vega de San Juan, Las Cruces, El Toro, El Diamante (all near Gachala), Mundo Nuevo, Buenavista, Chivor, Achiote Not all Colombian emeralds reached the Spanish und Sagrada Familia (near Somondoco). J. Gemm., 1991,22,6 357

subtropical mountain vegetation have made access 2. Main crystallization: calcite, pyrite, dolomite, for geological mapping and systematic prospecting quartz and emerald with the accessory minerals very difficult. parisite, albite, pink apatite and colourless fluorite, Apart from the mines of Muzo and Chivor - 3. Calcite, pyrite, dolomite and baryte. renowned worldwide for the quality and quantity of Parisite is a very rare, brownish Ca(Ce,La,Di)- their emeralds - there is supposedly a large number carbonate named after the Colombian Jose Ignacio of smaller, less important diggings and mines Paris (last century). (about 200), the names and locations of which are The northern part of the district of Chivor is less obscure or conflicting. Localities such as Borur, well explored than the Gachala and Muzo areas. In Borbur and Burbar are quoted, but it is conceivable Chivor the veins are known to be poor in calcite, but that all these names refer to one and the same rich in albite and pyrite, and found between or occurrence. The spelling of several mines also varies underneath nearly horizontal limonite beds. The in literature (Coscuez/Cosquez, Perias Blancas/Pena crystallization sequence is: Blanca, etc.). Apart from further mines in the 1. Pyrite and quartz, Colombian emerald belt, Kazmi & Snee (1989) 2. Pyrite, emerald and albite with subordinate mention an isolated occurrence in the Valle Andalu- apatite and dolomite. cia (240 km WSW of Bogota). Reports that emer Limonite (mainly goethite) on the one side and alds have been found as far south as Ecuador, micas (muscovite, sericite, fuchsite) plus clay however, have not been confirmed (Schwarz, minerals (kaolinite) on the other side are encoun 1989a). tered as dissociation products of pyrite and albite (the white feldspar). A second beryllium mineral, a Bl. Emerald deposits and their geological environ bluish euclase (BeAl[Si04]OH, monoclinic), has ment been detected in company with the emeralds of The Colombian emeralds occur in dark, carbo Gachala as well, although not often. naceous shales and thin, inter-layered limestones of Omnipresent minerals in Muzo are calcite and early Cretaceous age, that is, about 120 to 130 pyrite and in Chivor pyrite and albite. million years old. This rock series was formed of chalky and argillaceous, marine and continental B2. Hypotheses of emerald genesis sediments of high organic content and is therefore The genesis of the emerald deposits is controver grey to black in colour. Since the early Tertiary sial. The postulation put forward most frequently in period, they have been lifted, folded, faulted and literature is the formation from hydrothermal solu mineralized (Figure 1). tions. This conclusion has been reached by studies Emeralds appear enriched in places where large- of the paragenesis of the gangue (vein matrix) and of scale tectonic faults once cut through the sediments. the homogenization temperatures of multi-phase The Muzo district lies directly at the Rio Itoco fault inclusions in the emeralds (Kozlowski, et al. (1988) (striking NW-SE) and the Chivor district at the San suggesting a minimum temperature of the fluids of Fernando fault system (striking NE-SW). The 470°C, prior to taking into account a correction of at emeraldiferous lodes and veins follow the minor least + 100°C for an overburden pressure of ^ 1 lateral clefts as well. kbar). In the so-called Villeta series of Muzo and in the Fluid phases under pressure are exceptionally somewhat older Caqueza series of Chivor the veins mobile and can easily travel long vertical distances. form sills and often fill out cavities and steep As hydrothermal differentiation products of fissures. The emeralds preferably concentrate in the magmatic crystallization cycles, they are thought to lower fold axes of the carbonaceous shales but represent residual solutions which delivered the especially at intersections of veins and clefts. The light elements Si, Al, Na, (Mg) and in particular the crossings seem to have offered quieter crystalliza volatile beryllium. However, other origins of the tion conditions creating an easier migration of solutions such as fossil and possibly marine waters mineral forming solutions than in the actual veins. from rock pores containing sodium and chlorine In the district of Muzo the emerald-bearing lodes may be argued as well. and veins consist mainly of calcite and show Rising through the fracture systems and clefts in thicknesses of a few up to 300 millimetres. In the argillaceous, calcareous and evaporitic sedi contrast, veins with dolomite, albite and baryte are ments characteristic of these parts of the Cretaceous frequently barren of emeralds (sterile). The calcite succession, these brines in addition could have veins of Muzo are characterized by the following dissolved: succession of parageneses (chronological sequence 1. carbonates, sulphides, sulphates, fluorides, phos of mineral associations): phates and quartz, all observed as gangue minerals, 1. Calcite and pyrite, 2. the emerald colour-causing transition elements 358 J. Gemm., 1991, 22, 6

Cr and V plus Fe, This appears to have happened in the area of the 3. the element Be (Escovar, 1979) and mines El Diamante and Las Cruces near Gachala. 4. some rare earths (Ottaway, et al., 1986). In contrast, the wall rocks in the Muzo district are Generally it seems less likely that chromium and said to be unaltered. beryllium have been extracted or leached out from The third variant of the hydrothermal hypothesis the limestone and clay rocks (except in the Gachala of emerald formation involves circulating ground area), in contrast to vanadium which is well known waters. Such carbon dioxide-containing waters seep to be present geochemically in sediments with into inclined rock layers and fault systems, reach a organic constituents such as those in the dark certain depth and mineralize under the influence of shales. Correspondingly, vanadium is observed in heat and pressure. During their re-ascent, the elevated concentration in the Trapiche emeralds of waters become oversaturated due to decreasing the Muzo district (Hanni, 1982). In addition, hardly temperature and pressure so that their mineral

Fig. 1. Two specimens of carbonaceous shale with calcite veins (one with abundant pyrite) and a pale emerald crystal group, about 4cm in length. Ali specimens from the Colombian mining district. any metamorphic rocks, ultrabasic or acid bedrocks contents are precipitated on the side walls of the have been found in the wider vicinity of either clefts. mining district which could be considered as possi However, the postulation of hydrothermal forma ble sources of Cr and Be (major ophiolitic and tion must be re-examined iri view of the facts that granitic rocks are present in the western Colombian the hypersaline brines have been at temperatures of cordilleras only, associated with important plati up to 600°C and that in many places they have num and gold deposits). apparently not affected the wall rocks of the A variant of the hydrothermal hypothesis is the emerald veins at all. For the time being, the origins concept of metasomatism, in which process indi of beryllium, chromium and water (fossil rock vidual minerals of the wall rocks are not only porosity waters originally of marine provenance, leached out by the hot brines, but are replaced from depths of ^ 5000m?) also remain unexplained. materially (i.e. they are carbonatized and albitized). According to Kazmi & Snee (1989), the suture J.J. Gemm.,Gemm., 1991,22,61991, 22, 6 359359

zoneszones ofof ththee earth'earth'ss crustcrust contaicontainn ththee highesthighest outputoutput ofof 150,000150,000 ctct (1986).(1986). BecausBecausee ooff thethe clearclear potentiapotentiall forfor emeralemeraldd depositdepositss iinn ththee world.world. ExamExam concentrationconcentration ofof emeraldemeraldss inin larglargee clefts,clefts, tunnellingtunnelling plepless araree ththee broabroadd collisiocollisionn beltbelt betweebetweenn ththee IndianIndian iiss ththee preferrepreferredd methomethodd ofof mining.mining. sub-continentsub-continent andand ththe'e EurasiaEurasiann plateplate iinn NorthNorth Chivor, historicallhistoricallyy thethe oldestoldest minemine,, hahass hadhad PakistanPakistan anandd AfghanistanAfghanistan anandd ttoo a lesserlesser extentextent thethe productioproductionn peakpeakss andand totaltotal break-downbreak-downss sincesince thethe UralUral mountainmountainss andand ththee vicinityvicinity ofof ththee AfricaAfricann RiftRift timetimess ooff thethe Conquista.Conquista. AtAt presentpresent thethe outputoutput ValleValleyy (Egypt(Egypt,, TanzaniaTanzania,, Mozambique)Mo"ambique).. TheThe collicolli appearsappears toto bbee fairlfairlyy low.low. ChivorChivor was anandd stillstill isis sionsion ofof submarinesubmarine ultraultrabasi basicc rocksrocks anandd aciacidd plutons,plutons, essentiallyessentially anan open-pitopen-pit benchinbenchingg operationoperation,, butbut withwith theitheirr geochemicallygeochemically increaseincreasedd contentcontentss ooff therethere isis somesome undergrounundergroundd miningmining tootoo.. chromiumchromium anandd berylliuberylliumm respectivelyrespectively,, wouldwould alonealone ThThee mineminess neanearr GachaldGachala werweree discoverediscoveredd iinn 19531953 offeofferr thethe rarerare anandd favourablefavourable conditionconditionss foforr thethe anandd flourisheflourishedd durinduringg ththee fiftiefiftiess andand sixties.sixties. SinceSince formatioformationn ooff emeraldemeraldss iinn thesthesee suturesuture zones.zones. TheThe thethenn thethe emeraldsemeralds frofromm thesthesee minesmines areare hardlhardlyy everever CordillerCordilleraa OrientaOrientall inin ColombiColombiaa alsoalso representsrepresents a encounteredencountered oonn ththee gemgem market.market. collisiocollisionn zonzonee (in(in fronfrontt ofof ththee north-wesnorth-westt driftingdrifting GuyanGuyanaa plate)plate).. InIn ththee author'author'ss judgemenjudgementt (cf.(cf. C5C5.. InclusionsInclusions andand growthgrowth characteristicscharacteristics,, footnotfootnotee 7)7),, [[ManuscriptManuscript receivedreceived 19 19 March March 1990.] 1990. ] thethe ColombiaColombiann emeraldemerald belbeltt hashas yeyett ttoo givegive uupp thethe secretsecret ooff ititss possiblypossibly remoteremote chromiuchromiumm andand berylberyl liuliumm sources.sources. BibliographyBibliography AnonAnon,, 1961.1961. A neneww emeraldemerald finfindd inin Colombia.Colombia. Gems && Gemology,Gemology, XX,, 55,, 142-58.142-58. (Boru(Borurr emeralds)emeralds) B3.B3. The Mine Workings AreAremm J.E.J.E.,, 1987.1987. Color Encyclopedia of Gemstones,Gemstones, 2n2ndd eded.. VaVann SinceSince thethe endend ofof ththee laslastt centurcenturyy thethe ColombianColombian NostranNostrandd ReinholdReinhold Co.Co. Inc.,Inc., NeNeww York.York . (emeral(emeraldd survey)survey) Bancroft,Bancroft, P.,P., 1973.1973. The World's Finest Minerals and Crystals.Crystals. mineminess havhavee hahadd anan eventfueventfull history.history. AAtt timestimes thethe 158-9.158-9. VikingViking PressPress Inc.Inc.,, NeNeww YorkYork.. (Patrici(Patriciaa emerald)emerald) mineminess werweree inin privatprivatee handshands,, sometimessometimes thetheyy werewere Bank,Bank, H., H.,Henn, Henn, U., U., 1990: 1990: Geschliffener, Geschliffener, durchsichtiger,durchsichtiger, gelbbrauner gelb supervisedsupervised bbyy thethe GovernmenGovernmentt oorr thethe BancBancoo dede llaa Parisitbrauner aus Parisit Muzo, aus Kolumbien. Muzo, Kolumbien. Z.Dt.Gemm.Ges. Z .Dt.Gemm.Ges. 39, 39, RepublicaRepublica.. AlongsidAlongsidee thesthesee mormoree oror leslesss strictlystrictly 4,229-32.4, 229-32. (pari(parisit sitee data)data) Bariand,Bariand, P.,P., Poirot,Poirot, J.P.,J.P., 1985.1985. Larousse des pierres précieuses,pnicieuses, controllecontrolledd formformss ofof management,management, a toleratedtolerated blackblack 132-42.132-42. LibrairLibrairee LarousseLarousse,, ParisParis.. markemarkett fefedd bbyy thethe unorganizedunorganized guaqueroguaqueross (treasure(treasure ('Moctezuma(,Moctezuma'' grougroupp ofof emeraldemerald crystals,crystals, etc.)etc.) huntershunters)) hashas foforr a longlong timetime beebeenn aann importantimportant BauerBauer,, M.,M., 1896.1896. Edelsteinkunde. C.HC.H.. Tauchnitz,Tauchnitz, LeipziLeipzigg (2(2.. economieconomicc factorfactor.. TheseThese guaquerosguaqueros searchsearch ththee wastewaste Auf!.Aufl. 1909).1909). PreciouPreciouss StonesStones (1968)(.1968),, DoveDoverr Publ.Pub!.,, NewNew washed down to the river beds below the mines. YorkYork (republication(republication ofof ththee firsfirstt EnglisEnglishh editioeditionn ofof Precious washed down to the river beds below the mines. Stones (1904),(1904), ChCh.. GriffinGriffin,, London).London). NationalizeNationalizedd mininminingg alsalsoo sufferedsuffered heavyheavy losseslosses afterafter Beus,Beus, A.A.A. A.,, Mineev,Mineev, D.A.D.A.,, 1972.1972. Some geological and geochemical ththee closureclosure ofof ththee MuzMuzoo mineminess frofromm 19731973 toto 19771977 featuresfeatures of the the Muzo-Coscuez emerald emerald zone, zone, Cordillera Cordillera Oriental, Orien duedue toto a seriesseries ofof murdersmurders.. TodaTodayy thethe wholwholee districtdistrict Colombia.tal, Colombia. Empresa Empresa Colombiana Colombiana de Minas, de Biblioteca Minas, Biblioteca is a prohibited area, closely guarded by the army. (unpubl.)(unpub!.),, 5555 pp.pp. is a prohibited area, closely guarded by the army. Biesalski,Biesalski, E.E.,, 1957.1957. Pflanzenfarbenatlas DIN 6164. MusterMuster- SinceSince 19781978 privateprivate companiescompanies werewere givengiven miningmining schmidt-Verlaschmidt-Verlagg Gottingen.Göttingen. leaseleasess bbyy thethe StateState foforr fivefive yearyear periodsperiods.. ItIt isis saidsaid thatthat (Wes(Westt GermanGerman ColouColourr CharChartt Atlas)Atlas) suchsuch shortshort contractscontracts (today(today thethe leasesleases areare foforr tenten Blak,Blak, A.R.A.R.,, IsotaniIsotani,, S.,S., Watanabe,Watanabe, S.,S., 1982.1982. OpticaOpticall AbsorptionAbsorption anandd ElectroElectronn SpinSpin ResonanceResonance iinn BlueBlue anandd GreenGreen NaturalNatural years)years) forceforce thethe managementmanagementss toto ususee dynamitedynamite asas BerylBery!.. Phys.Chem.MineralsPhys.Chem.Minerals,, 88,161-6., 161-6. welwelll aass bulldozersbulldozers andand pressurizepressurizedd waterwater ttoo movemove BosshartBosshart,, G.,G., 1982.1982. DistinctionDistinction ofof naturanaturall anandd synthetisyntheticc rubiesrubies larglargee rocrockk massesmasses.. ThiThiss isis a ververyy questionablequestionable bbyy ultra-violeultra-violett spectrophotometry.J.Gemm.spectrophotometry. J .Gemm. 18,2,145-60.18, 2, 145-60. developmendevelopmentt iinn operatingoperating ththee minesmines,, withwith immenseimmense (evaluation(evaluation ofof thethe UUVV absorptioabsorptionn behavioubehaviourr ooff chromiferouschromiferous effects on the ecology of the environment. minerals)minerals) effects on the ecology of the environment. BosshartBosshart,, G.G.,, Frank,Frank, E.E.,, Hanni,Hänni, H.A.,H.A., Barot,Barot, N.N.,, 1982.1982. BlueBlue OverOver thethe centuries,centuries, thethe Muzo mineminess havhavee yieldedyielded colour-changingcolour-changing kyanitkyanitee fromfrom EasEastt Africa.Africa. J.GemmJ.Gemm,, 18,18, 33,, bbyy fafarr thethe largeslargestt andand mosmostt constanconstantt productioproductionn ooff 205-12205-12.. emeralemeraldd iinn ththee worldworld (1986(1986 estimatedestimated toto bbee anan Bowersox,Bowersox, G.W.G.w.,, 1985.1985. A statusstatus reporreportt onon gemstonegemstoness fromfrom enormous 300,000 ct). Until approximately 20 years AfghanistanAfghanistan.. Gems & Gemology,Gemology, 21,21, 4,192-204.4, 192-204. enormous 300,000 ct). Until approximately 20 years (Panjsher(Panjsher emeraldsemeralds withwith 3-phas3-phasee inclusions)inclusions) agoago,, thesthesee minesmines werweree workeworkedd almostalmost exclusivelexclusivelyy byby CIBJO (Confederation(Confédération Internationale de la Bijouterie, Joaillerie,Joaillerie, open-castopen-cast methodmethodss inin smallsmall terracesterraces,, bubutt frofromm thenthen Orjevrerie,Orfèvrerie, des diamants, perles et pierres, 1988). Gemstone onon byby massivmassivee removaremovall ofof completecomplete rocrockk layerslayers.. BookBook,, ArtArt.. 55aa andand e.e. Presently it is planned to convert to modern (Rules(Rules ooff ApplicatioApplicationn forfor treatetreatedd emeralds)emeralds) Presently it is planned to convert to modern DeerDeer,, W.A.,W.A., HowieHowie,, R.A.R.A.,, ZussmanZussman,, J.J.,, 1972.1972. An Introduction to undergrounundergroundd mining.mining. the Rock Forming Minerals. LongmanLongman,, London.London. ThThee neighbourinneighbouringg Coscuez minminee hahass alsalsoo beenbeen Deer,Deer, W.A.W.A.,, Howie,Howie, R.A.,R.A., ZussmanZussman,, J.J.,, 1986.1986. Rock Forming workedworked forfor 404000 years,years, bubutt thisthis deposidepositt hahass beenbeen Minerals, vol. 1BIB Disilicates and Ring Silicates. LongmanLongman ScientificScientific & Technical,Technical, JohnJohn WileWileyy & Sons,Sons, NeNeww York.York. markemarkedd bbyy longlong periodperiodss ofof inactivityinactivity.. InIn ththee paspastt fewfew DesautelsDesautels,, P.E.P.E.,, 1979.1979. TreasuresTreasures iinn thethe SmithsonianSmithsonian - TheThe GemGem years,years, howeverhowever,, CoscueCoscuezz hahass overtakenovertaken ChivoChivorr asas thethe Collection.Collection. Smiths.Inst.,Smiths.Inst., WashingtonWashington DC.DC. secondsecond largeslargestt produceproducerr withwith aann estimateestimatedd yearlyyearly (emeral(emeraldd cat's-eycat's-eyee 4.4.66 ctct,, nono.. 2256)2256) 363600 JJ.. Gemm.Gernrn.,, 19911991,22,6, 22, 6

DiehlDiehl,, R.R.,, 19761976.. DeDerr physikalisch-chemischphysikalisch-chemischee BegrifBegrifff dederr KleinKlein,, F.F.,, 19511951.. Smaragde unter dem Urwald. VerlaVerlagg FF.. KleinKlein,, 'Phase''Phase:. Z.Dt.Gemmol.Ges.Z.Dt.Gemmol.Ges.,, 2525,, 44,, 211-3211-3.. Idar-ObersteinIdar-Oberstein.. (meanin(meaningg ooff ththee tertermm 'phase')'phase') KoivulaKoivula,, J.I.J.I.,, KammerlingKammerling,, R.C.R.e.,, 1989a1989a.. EmeralEmeraldd imitationimitation EpplerEppler,, W.F.WF.,, 19641964.. EinschlüssEinschliissee iinn EdelsteineEdelsteinenn (30(30.. EinschlüssEinschliissee frofromm quartzquartz.. GemsGems& & Gemology (Ge(Gemm News)News),, 2525,1,50-1., 1, 50-1. iimm SmaragSmaragdd vovonn Burbar)Burbar).. Goldschmiede-ZeitungGoldschmiede-Zeitung,, 1010,64., 64. KoivulaKoivula,, J.I.J.I.,, KammerlingKammerling,, R.C.R.e.,, 1989b1989b.. TunnelTunnelss useusedd ttoo minminee (Burba(Bur barr emeralds)emeralds) emeraldemeraldss aatt MuzoMuzo.. Gems & Gemology (Ge(Gemm News)News),, 2525,, 22,, EpplerEppler,, W.F.WF.,, 19731973.. Praktische Gemmologie. Riihle-DiebenerRühle-Diebener 112112.. VerlagVerlag,, Stuttgart.Stuttgart. Koivula,Koivula, J.I., J.I., Kammerling, Kammerling, R.C.,R.e., 1989c. 198.9c. Santa Santa Terezinha Terezinha emerald emer (gemmologica(gemmologicall datdataa anandd inclusioninclusionss ooff ColombiaColombiann emeralds)emeralds) ald treatmenttreatment.. GemsGems& & Gemology (Ge(Gemm News)News),, 2525,, 33,, 180-1180-1.. EscovarEscovar,, R.R.R.R.,, 19791979.. GeologíGeologiaa y geoquímicgeoquimicaa ddee lalass minaminass ddee ('Opticon('Opticon'' fracturfracturee sealant)sealant) esmeraldaesmeraldass ddee GachaláGachahi,, CundinamarcaCundinamarca.. Bol.Geol.Bol.Geol.,, 2222 (3)(3),, Kozlowski,Kozlowski, A., Metz, A., Metz,P., Jaramillo, P., Jaramillo, H.A.E., H.A.E., 1988. 1988. Emeralds Emeralds 117-53117-53.. (berylliu(berylliumm frofromm ththee walwalll rocksrocks)) frofromm SomondocoSomondoco,, ColombiaColombia:: chemicachemicall compositioncomposition,, fluidfluid FeatherFeather,, R.C.R.e.,, 19901990.. ParisitParisitee iinn emeraldemerald.. Lap.J.Lap.].,, 8/90.8/90. inclusioninclusionss anandd originorigin.. N.Jb.Miner.Abh.N.Jb.Miner.Abh.,, 159159,, 11,23-49., 23-49. FryerFryer,, C.W.e.W,, 19901990.. EmeraldEmerald,, witwithh fillefilledd fracturesfractures.. Gems & Larsen, E.S., E.S., Berman, Berman, H., H.,1964. 1964. The TheMicroscopic Microscopic Determination Determina GemologyGemology,, GeGemm TradTradee LaLabb NotesNotes,, 2626,, 11,95-6., 95-6. oftion the ofthe Non-opaque Non-opaque Minerals. Minerals. USGS Bull.,USGS 848, Bull., 2nd 848,ed. 2nd ed. (Yehud(Yehudaa fracturfracturee fillingfillingss iinn emeralds)emeralds) (specifi(specificc refractivities)refractivities) FujisakiFujisaki,, Y.Y.,, 19761976.. InclusionInclusionss iinn EmeralEmeraldd frofromm MuzoMuzo,, Colombia.Colombia. LebedevLebedev,, A.S.A.S.,, IlyinIlyin,, A.G.A.G.,, KlyakhinKlyakhin,, V.A.V.A.,, 19831983.. VariétéVarietess ddee J.Gemm.Soc. Jap.Jap.,, 33,, 44,, 157-6157-644 (Englis(Englishh abstract)abstract).. béryberyll gemmgemmee hydrothermalhydrothermal.. Rev.gemm. a.f.g.a.f.g.,, 7676,4-5., 4-5. (or(oree mineraminerall inclusions)inclusions) (bery(beryll chromophores)chromophores) GeoskopGeoskop,, 19841984.. PlattentektonikPlattentektonik.. ImmeImmerr weiteweilerr bibiss Amerika.Amerika. Leithe-JasperLeithe-Jasper,, M.M.,, DistelbergerDistelberger,, R.R.,, 19821982.. Kunsthistorisches Geo. 1111,238-240., 238-240. Museum WienWien,, 2929.. VerlaVerlagg C.He.H.. BeckBeck,, Miinchen.München. (curren(currentt continentacontinentall drifdriftt rateratess anandd directions)directions) (larges(largestt polishepolishedd ColombiaColombiann emerald)emerald) GrundmannGrundmann,, G.G.,, MorteaniMorteani,, G.G.,, 19891989.. EmeralEmeraldd MineralizationMineralization LindLind,, T.T.,, SchmetzerSchmetzer,, K.K.,, BankBank,, H.H.,, 19861?86.. BluBluee anandd greegreenn berylberylss durinduringg RegionaRegionall MetamorphismMetamorphism,, ThThee HabachtaHabachtall (Austria)(Austria) (aquamarine(aquamariness anandd emeraldsemeralds)) ooff gegemm qualitqualityy frofromm Nigeria.Nigeria. andand Leydsdorp Leydsdorp (Transvaal, (Transvaal, South Africa) Africa) Deposits. Deposits. Economic Econo J.Gemm.J.Gemm.,, 2020,, 1,40-8.1, 40-8. mic Geology,Geology, 8484,, 1835-49.1835-49. (beryllium)(beryllium) MartinMartin,, D.D.D.D.,, 1987.1987. GemstonGemstonee DurabilityDurability:: DesigDesignn ttoo display.display. Giibelin, Gübelin,E.J., 1973. E.J., 1973.Internal Internal World World of ofGemstones. Gemstones. 1st 1st ed.,ed., Gems & GemologyGemology,, 2323,, 33,, 63-7763-77.. 29,49,53,61,76,143,145,150-229,49,53,61,76,143,145,150-2.. ABABCC EditionsEditions,, Zurich.Zurich. MedenbachMedenbach,!, O.0.,, WilkWilk,, H.H.,, 1977.1977. Zauberwelt der Mineralien,Mineralien, (inclusio(inclusionn micrographmicrographss ooff ColombiaColombiann emeralds)emeralds) 192-194192-194.. SiglochSigloch EditionEdition,, KünzelsauKiinzelsau,, ThalwilThalwil,, Salzburg.Salzburg. GübelinGiibelin,, E.J.E.J.,, 19821982.. DiDiee EdelsteinvorkommeEdelsteinvorkommenn Pakistans,Pakistans, (larg(largee formaformatt photphotoo ooff ColombiaColombiann emerald)emerald) 2.Teil2.Teil.. DiDiee SmaragdvorkommeSmaragdvorkommenn iimm Swat-Tal.Swat-Tal. LapisLapis,, VIVI,, MeenMeen,, V.B.V.B.,, TushinghamTushingham,, A.D.A.D.,, 1969.1969. Crown Jewels of Iran.Iran. 19-2619-26 anandd 4242.. (Swa(Swatt ValleValleyy emeralds)emeralds) UniversitUniversityy ooff TorontTorontoo PressPress,, Toronto.Toronto. GübelinGiibelin,, E.J.E.J.,, KoivulaKoivula,, J.I.J.I.,, 1986.1986. Photoatlas of Inclusions in MenzhausenMenzhausen,, JJ,, 1987.1987. The Green Vaults, an IntroductionIntroduction,, 13th13th Gemstones. ABABCC EditionsEditions,, Zurich.Zurich. ed.ed.,, 9191.. StatStatee ArArtt CollectionsCollections,, Dresden.Dresden. (frequen(frequentt anandd rarraree ColombiaColombiann inclusions)inclusions) (historica(historicall ChivoChivorr group)group) HänniHanni,, H.A.H.A.,, 1982.1982. A contributiocontributionn ttoo ththee separabilitseparabilityy ooff naturalnatural NassauNassau,, K.K.,, JacksonJackson,, 1970.1970. TrapichTrapichee EmeraldEmeraldss frofromm ChivoChivorr andand anandd synthetisyntheticc emeraldsemeralds.J.Gemm.,. J.Gemm., XVIIIXVIII,, 22,138-44., 138-44. MuzoMuzo,, ColombiaColombia.. Am.Min.Am.Min.,, 5555,, 416-2416-277 (correctio(correctionn 1808-1809).1808- HänniHanni,, H.A.H.A.,, 1988a.1988a. WenWennn eess eieinn OlfeldÖlfeld iimm GarteGartenn gibt.gibt. Nassau1809)., K. , 1978. Trapiche-Smaragde von Muzo. Lapis, IV, Schweiz.Uhrm.Goldschm.Z.Schweiz. Uhrm.Goldschm.Z.,, 33,461-4., 461-4. Nassau, K., 1978. Trapiche-Smaragde von Muzo. Lapis, IV, (aspects(aspects ofof emeraldemerald treatment)treatment) 20-2320-23 undund 4040.. Hanni,Hänni, H.A.,H.A., 1988b.1988b. CertitudeCertitude dede lala determinationdétermination dede I'originel'origine NassauNassau,, K.,K., 1984.1984. Gemstone Enhancement. Butterworths,Butterworths, desdes gemmes.gemmes. Rev.gemm. a.f.g.,a.f.g., 97,97, 4-54-5.. LondonLondon.. (reliability(reliability degreesdegrees ofof originorigin determination)determination) NiedermayrNiedermayr,, G.,G., 1989a.1989a. DieDie EdelsteinsammlungEdelsteinsammlung imim NaturhisNaturhis- HennHenn,, U.,U., 1988.1988. UntersuchungenUntersuchungen anan SmaragdenSmaragden ausaus demdem torischentorischen MuseumMuseum inin WienWien.. Goldschmiede- und UhrmacherUhrmacher- Swat-Tal,Swat-Tal, Pakistan.Pakistan. Z.Dt.Gemmol.Ges.,Z.Dt.Gemmol.Ges., 37,37, 3/4,121-7.3/4, 121-7. Zeitung, 11/89.11/89. (Colombian(Colombian emeralds)emeralds) Hiss,Hiss, D.A,D.A, Holmes,Holmes, G.,G., 1989.1989. ColorColor Enhancement:Enhancement: HowHow toto telltell Niedermayr,Niedermayr, G.,G., 1989b.1989b. TheThe MineralMineral CollectionCollection ofof thethe MuseumMuseum youryour customer.customer. Jewelers' Circular-Keystone, 321-36.321-36. ofof NaturaNaturall History,History, Vienna.Vienna. Mineralogical RecordRecord,, 20,20, 347-347-54. Huffer,Huffer, H.,H., 1983.1983. TreatedTreated GemsGems - whywhy notnot facfacee thethe facts?facts? Niedermayr54. , G., 1990. Weitere Fluorit-Vorkommen in Europa Jewelers' Circular-Keystone,Circular-Keystone, MayMay 1983,1983, 33-80.33-80. Niedermayr, G., 1990. Weitere Fluorit-Vorkommen in Europa Hughes,Hughes, R.W,R.W., 1990.1990. A QuestionQuestion ofof Origin.Origin. Gemology Digest, 33,, undund ÜberseeUbersee.. Emser, Hefte II,11, 3,3, 76.76. (Muzo(Muzo fluorites)fluorites) 1,16-32.1, 16-32. Ottaway,Ottaway, T.L.,T.L., Wicks,Wicks, F.J.,F.J., Bryndzia,Bryndzia, L.T.,L.T., Spooner,Spooner, E.T.e.,E.T.C., JohnsonJohnson,, P.W,P.W., 1961.1961. TheThe ChivorChivor EmeraldEmerald Mine.Mine. J.Gemm.,J.Gemm., 1986.1986. CharacteristicsCharacteristics andand originorigin ofof thethe MuzoMuzo emeraldemerald VIII,VIII, 4,4, 126-52.126-52. deposit,deposit, ColombiaColombia (abstract).(abstract). International Mineralogical Kane,Kane, R.E.,R.E., KammerlingKammerling,, R.e.,R.C., Moldes,Moldes, R.,R., Koivula,Koivula, J.I.J.I. Association. Abstr.,Abstr., 193193.. McClure, S.F.,S.F., Smith, Smith, C.P., e.P., 1989. 1989. Emerald Emerald and Goldand Gold Treasures Trea Ponahlo,Ponahlo, ].,J., 1989.1989. MikrospektralphotometrieMikrospektralphotometrie derder EdelsteinEdelstein- sures ofof thethe SpanishSpanish GalleonGalleon NuestraNuestra SenoraSeñora dede Atocha.Atocha. Kathodolumineszenz.Kathodolumineszenz. Z.Dt.Gemmol.Ges.,Z.Dt.Gemmol.Ges., 38,38, 2/3,2/3, 63-84.63-84. Gems&Gems & GemologyGemology,, 2525,, 4,4,196-206. 196-206. (identification(identification ofof oiloil treatment)treatment) Kazmi,Kazmi, A.H.,A.H., Snee,Snee, L.W,L. W., 1989.1989. Emeralds of Pakistan-Geology,Pakistan - Geology, Rainier,Rainier, P.W,P.W., 1943.1943. Green Fire. JohnJohn MurrayMurray Publishers,Publishers, Gemology, & Genesis. GeologicalGeological SurveySurvey ofof PakistanPakistan & VanVan London.London. NostrandNostrand ReinholdReinhold Co.,Co., NewNew York.York. Ringsrud,Ringsrud, R.,R., 1983.1983. TheThe OilOil TreatmentTreatment ofof EmeraldsEmeralds inin Bogota.Bogotá. (monograph(monograph aboutabout PakistanPakistan andand AfghanAfghan emeraldemerald deposits)deposits) Gems&Gems & Gemology,Gemology, 19,3,149-56.19, 3, 149-56. Ringsrud, R., 1986. The Coscuez Mine. Gems & Gemology, 22, Keller,Keller, P.e.,P.C., 1981.1981. EmeraldsEmeralds ofof Colombia.Colombia. Gems&Gems & Gemology,Gemology, 17,17, Ringsrud, R., 1986. The Coscuez Mine. Gems & Gemology, 22, 2,80-92.2, 80-92. 2,67-79.2, 67-79. Keller,Keller, P.e.,P.C., 1990.1990. Gemstones and theirtheir origins. VanVan NostrandNostrand Roberts,Roberts, WL.,W.L., Rapp,Rapp, G.R.G.R. Weber,Weber, J.,J., 1974.1974. Encyclopedia of Reinhold,Reinhold, NewNew York.York. Minerals. VanVan NostrandNostrand ReinholdReinhold Co.,Co., NewNew York.York. Kiefert, L., L., Schmetzer, Schmetzer, K., K., 1990. 1990. Die Diemikroskopische mikroskopische Bestimmung Bestim (parisite,(parisite, MuzoMuzo emeralds,emeralds, zeoliteszeolites etc.)etc.) mung strukturellerstruktureller MerkmaleMerkmale optischoptisch einachsiger,einachsiger, natiirnatür- Robinson,Robinson, G.W,G.W., King,King, V.T.,V.T., 1989.1989. What'sWhat's newnew inin Minerals?Minerals? licherlicher undund synthetischersynthetischer Edelsteine.Edelsteine. TeilTeil 2.2. GoldschmiedeGoldschmiede- Mineralogical Record,Record, 20,20, 392,392, 394.394. Zeicung,Zeitung, 1/90,1/90, 157-62. 157-62. (new(new MuzoMuzo emeraldsemeralds ofof exceptionalexceptional quality)quality) (identification(identification ofof authenticityauthenticity andand originorigin withwith thethe aidaid ofof growthgrowth Roedder,Roedder, E.,E., 1982.1982. FluidFluid InclusionsInclusions inin Gemstones:Gemstones: ValuableValuable structures)structures) Defects.Defects. GIAGIA InternationalInternational GemologicalGemological SymposiumSymposium Pro-Proceedings, J.J. Gemm.Gemm.,, 1991,22,61991,22,6 361361

ceedings, 482-502.482-502. (Colombia(Colombiann multiphasmultiphasee inclusions)inclusions) InstitutoInstituto EcuatorianEcuatorianoo dede Mineria,Mineria, Quito.Quito. Schafer,Schäfer, w.,W., 1984.1984. DiDiee kolumbianischenkolumbianischen Smaragd-LagerstattenSmaragd-Lagerstätten (emerald(emerald occurrencoccurrencee iinn Ecuador?)Ecuador?) MuzMuzoo unundd Chivor.Chivor. LapisLapis,, IVIV,, 9-239-23 anandd 5050.. Schwarz,Schwarz, D.,D., 1989b.1989b. SmaragdabbauSmaragdabbau iinn KolumbienKolumbien,, neueneue (Muzo(Muzo andand ChivorChivor minminee reportsreports oftheof the eighties)eighties) AspekteAspekte.. Z.Dt.Gemmol.Ges.Z.Dt.Gemmol.Ges.,, 38,38, 4,155-60.4, 155-60. SchäferSchafer,, w.,W., 1987a.1987a. AuAuff SafariSafari zzuu dedenn Smaragdminen.Smaragdminen. Schmuck (lates(latestt ColombianColombian productioproductionn andand exporexportt figures)figures) & Uhren,Uhren, 3,3, 36-41.36-41. Schwarz,Schwarz, D.D.,, 1990a.1990a. DieDie brasilianischenbrasilianischen SmaragdeSmaragde undund ihreihre Schafer,Schäfer, w.,W., 1987b.1987b. GrüneGriiness Fieber,Fieber, TeiTeill.l 1. Schmuck & Uhren,Uhren, 66,, Vorkommen:Vorkommen: SantaSanta TerezinhaTerezinha ddee GoiásGoias.. Z.Dt.Gemmol.Ges.,Z.Dt.Gemmol.Ges., 19-21.19-21. 39,39, I,1, 13-44.13-44. (Brazilia(Braziliann emeralds)emeralds) Schafer,Schäfer, w.,W., 1987c.1987c. GriinesGrünes FieberFieber,, Teil2.Teil 2. Schmuck & Uhren,Uhren, 99,, SchwarzSchwarz,, D.D.,, 1990b,1990b, personapersonall communication.communication. 24-724-7.. Schwarz, D., D., 1991. 1991. Die Die chemischen chemischen Eigenschaften Eigenschaften der Smaragde. der Smar Schafer,Schäfer, w.,W., 1987d.1987d. HimmlischeHimmlische TränenTranen,, TeiTeill I.1. Schmuck && agde. TeilTeil 44,, KolumbienKolumbien.. Z.Dt.Gemmol.Ges.Z.Dt.Gemmol.Ges.,, mehrteiligemehrteilige Uhren,Uhren, 10,10, 35-835-8.. SerieSerie (i(inn Vorbereitung).Vorbereitung). SchäferSchafer,, w.,W., 1987e.1987e. HimmlischeHimmlische Tranen,Tränen, TeiTeill 2.2. Schmuck && (The chemical chemical properties properties of ofemeralds. emeralds. Series Series in preparation) in preparation) Uhren,Uhren, 11,11, 36-836-8.. Sinkankas,Sinkankas, ].,J., 1981.1981. Emeralds and other Beryls. ChiltoChiltonn BookBook Schmassmann,Schmassmann, H.,H., 1980.1980. Geologie undund GeneseGenese der der schweizerischen schweizerischen CompanyCompany,, RadnorRadnor PaPa.. Mineral- und Thermalwiisser.Thermalwässer. Sonderdruck aus OltOOtto Hiirgl:Hörgl: Stockton,Stockton, C.M.,C.M., 1984.1984. TheThe chemicalchemical distinctiodistinctionn ofof naturanaturall fromfrom Die Mineral- und Heilquellen der Schweiz, 47-10047-100.. VerlagVerlag syntheticsynthetic emeralds.emeralds. Gems&Gems & Gemology,Gemology, 20,20, 3,141-5.3, 141-5. PauPaull HauptHaupt,, BetnBern undund Stuttgart.Stuttgart. Stockton,Stockton, C.M.C.M.,, 1987.1987. TheThe separatioseparationn ofof naturalnatural frofromm syntheticsynthetic (geology(geology anandd genesigenesiss ofof mineraminerall anandd thermathermall waters)waters) emeraldemeraldss bbyy infrareinfraredd spectroscopyspectroscopy.. Gems&Gems & GemologyGemology,, 2323,, 2,2, Schmetzer,Schmetzer, K.,K., 1978.1978. Vanadium III als FarbtriigerFarbträger bei naturlichennatürlichen 96-9.96-9. Silikaten und Oxiden - ein Beitrag zur Kristallchemie des Superchi,Superchi, M.,M., RolandiRolandi,, V.V.,, 1980.1980. A proposaproposalforl for delimitindelimitingg rubyruby Vanadiums. ThesisThesis,, Univ.Univ. Heidelberg.Heidelberg. (from(from roserose anandd violeviolett corundumcorundum)) andand emeraldemerald (from(from lightlight (vanadiu(vanadiumm IIIIII chromophorchromophoree inin silicatesilicatess anandd oxides)oxides) greegreenn andand darkdark greegreenn beryl)beryl).. Z.Dt.Gemmol.Ges.Z.Dt.Gemmol.Ges.,, 29,29, 112,1/2, Schmetzer,Schmetzer, K.,K., 1982.1982. AbsorptionsspektroskopiAbsorptionsspektroskopiee undund FarbeFarbe vonvon 68-7068-70.. V3+V3+-haltigen -haltigen natiirlichen natiirlichen Oxiden Oxiden und Silikatenund Silikaten - ein Beitrag - ein Bei Taylor,Taylor, A.M.,A.M., 1977.1977. EmeraldEmeraldss anandd EmeraldsEmeralds.. J.Gemm.J.Gemm.,, XVXV,, 77,, zurtrag Kristallchemie zur Kristallchemie des Vanadiums. des Vanadiums. N.Jb.Miner.Abh. N.Jb.Miner.Abh.,, 372-7.372-7. (emeral(emeraldd typestypes I andand II)II) 144,144, 1,73-106.1, 73-106. TroupTroup,, G.J.G.].,, Hutton,Hutton, D.R.D.R.,, 1983.1983. ThThee useuse ofof electroelectronn spinspin Schmetzer,Schmetzer, K.,K., 1988.1988. CharacterizatioCharacterizationn ofof RussiaRussiann hydrotherhydrother- resonance spectroscopy spectroscopy to todistinguish distinguish synthetic synthetic from from natural natu mallymally growgrownn syntheticsynthetic emeralds.J.Gemm.,emeralds. J.Gemm., 21,21, 33,145-64., 145-64. gemstones.ral gemstones.J.Gemm., J.Gemm., 18, 5, 421-31. 18, 5, 421-31.. Schmetzer,Schmetzer, K.,K., 1989.1989. TypesTypes ooff watewaterr iinn naturalnatural anandd syntheticsynthetic (syntheti(syntheJicc andand naturanaturall emeraldemerald ESESRR spectra)spectra) emerald.emerald. N.Jb.Miner.Mh., 1,1, 15-26.15-26. Trueb,Trueb, L.L.,, 1989.1989. FlüssigFliissigee PhasePhasenn imim tiefetiefenn Krustengestein.Krustengestein. Schmetzer,Schmetzer, K.,K., BankBank,, H.,H., 1981.1981. AnAn unusuaunusuall pleochroispleochroismm iinn Neue ZürcherZurcher Zeitung, Forschung und Technik,Technik, 230230,, 828L. ZambiaZambiann emeraldsemeralds.J.Gemm.,. J.Gemm., 17,7,443-6.17, 7, 443-6. (fluid(fluid phasephasess inin deedeepp crustcrust rocks)rocks) Schrader,Schrader, H.W.H.W.,, 1983.1983. ContributionContributionss ttoo thethe studystudy ofof thethe WaltonWalton,, J.].,, 1950.1950. UnusuaUnusuall emeraldemerald.. Gemmologist,Gemmologist, 19,19, 123-5123-5.. distinctiodistinctionn ofof naturanaturall andand synthetisyntheticc emeraldsemeralds.J.Gemm.,. J. Gemm., 18,18, (parisit(pari sitee data)data) 66,530-43., 530-43. Ward,Ward, F.F.,, 1990.1990. TheThe TimelesTimelesss MystiquMystiquee ofof EmeraldsEmeralds.. NationalNational Schrader,Schrader, H.W.H.W.,, 1985.1985. 'Dreiphasen-Einschluss'Dreiphasen-Einschluss'' iinn einemeinem Geographic MagazineMagazine,, 7,7, 38-6938-69.. SmaragdSmaragd auauss Siidafrika.Südafrika. Z.Dt.Gemmol.Ges.,Z.Dt.Gemmol.Ges., 3434,, 3/43/4,130-1., 130-1. Wegener,Wegener, A.,A., 1929.1929. Die Entstehung der Kontinente und Ozeane. 4.4. (3-phas(3-phasee inclusionsinclusions,, CobraCobra mine)mine) rev.rev. Aufl.Aufl. VieweViewegg & Sohn,Sohn, BraunschweigBraunschweig.. The Origin of Schwarz,Schwarz, D., D.,1987. 1987. Esmeraldas Esmeraldas - Inclusoes- Inclusôes em em Gemas. Gemas. Universi Universidade Continents and Oceans,Oceans, 1966.1966. DoverDover PublPub!.. Inc.Inc.,, NeNeww York.York. dadeFederal Federal de Ouro de Preto, Ouro 1st Preto, ed. Emeralds, 1st ed. Emeralds, 2nd rev. and 2nd rev. and WoodWood,, D.L.,D.L., NassauNassau,, K.,K., 1968.1968. ThThee CharacterizatioCharacterizationn ooff BerylBeryl ext.ext. eded.. (i(inn preparation).preparation). and EmeraldEmerald by by visible visible and andinfrared infrared absorption absorption spectroscopy. spectro (geology,(geology, occurrencesoccurrences,, chemicalchemical andand opticaopticall datdataa ofof emeraldsemeralds scopy. American MineralogistMineralogist,, 5353,, 777-800.777-800. etc.)etc.) (beryl(beryl absorption absorption spectra spectra and andallocation allocation of chromophores) of chromophores) Schwarz,Schwarz, D.D.,, 1989a,1989a, personapersonall communicatiocommunicationn ofof a replreplyy bbyy thethe 363622 JJ.. Gemm. Gemm.,, 1991,22,1991 , 22,66

THTHEE GEMMOLOGICA GEMMOLOGICALL GEGEMM TESTINTESTINGG OOFF GREA GREATT ThThee singl singlee organizatio organizationn fo forr everyon everyonee

WWee offe offerr a comprehensiva comprehensivee rang rangee o fof gemmologica gemmologicall service servicess t oto ou ourr membersmembers,, student studentss an andd other otherss wit withh a commerciaa commerciall o ror professiona professionall interestinterest.. ^r-feS EDUCATIOEDUCATIONN ThThee Diplom Diplomaa Cours Coursee in inGemmolog Gemmologyy (leadin(leadingg to toFellowshi Fellowshipp - FGA- FGA) ) WeWe tak takee prid pridee in in ou ourr internationa international reputatiol reputationn as as a learnea learnedd societ societyy dedicate dedicatedd to toth ethe promotio promotionn of of gemmologicagemmologicall educatio educationn an andd th ethe sprea spreadd of of gemmologicagemmologicall knowledge knowledge.. ThThee Diplom Diplomaa Cours Coursee ha hass bee beenn speciall speciallyy compile compiledd int intoo a a serieseriess of ofteachin teachingg module moduless tha thatt ar eare bot bothh readabl readabe lean andd lavishl lavishlyy illustratedillustrated.. Thes Thesee course coursess provid providee a comprehensiv a comprehensivee step-by-ste step-by-stepp guid guidee to toth ethe fascinatin fascinatingg worl wodrl odf ofgemmolog gemmologyy an andd an an opportunit opportunityy to toear earnn th ethe covete covetedd initial initials s FGFGAA - Fello - Felloww of ofth ethe Gemmologica Gemmologicall Association Association.. INSTRUMENTSINSTRUMENTS,, BOOK BOOKSS AN ANDD SPECIMEN SPECIMENSS ThrougThroughh ou ourr Instrument Instrumentss Divisio Divisionn w ewe ar eare abl ablee to tosuppl supplyy gemmologicagemmologicall instruments instruments,, gemston gemstonee an andd jeweller jewelleryy relaterelatedd books books,, audiovisua audiovisuall materia maleriall an andd gemston gemstonee specimensspecimens.. Th Thee showroo showroomm is opeis openn durin duringg norma normall officofficee hour hourss whe whenn exper expertt assistanc assistancee is availableis available. . JJ.. Gemm.Gemm.,, 1991,22,61991,22,6 363363

ASSOCIATIOASSOCIATIONN ANANDD LABORATORLABORATORYY BRITAIBRITAINN witwithh aann interesinterestt iinn gemstonesgemstones..

BByy makinmakingg ususee ooff ththee comprehensivcomprehensivee catalogu£catalogue you^ can order goods by mail, telephone oorr fafaxx frofromm anywheranywheree iinn ththee worlworld.d GEMSTONGEMSTONEE TESTINGTESTING THTHEE JOURNALJOURNAL OFOF ANANDD RESEARCRESEARCHH GEMMOLOGGEMMOLOGYY AA fulfulll gemstongemstonee ThThee JournaJoumal l iiss amonamongg identificatioidentificationn anandd ththee mosmostt respected^ of researcresearchh servicservicee iiss ititss typtypee iinn ththee worldworld.. offereofferedd ttoo membersmembers.. Papers on all aspects ThThee QeGemm TfestinTestingg of.gemstonei«of gemstone research^ LaboratorLaboratoryy arepublisheare publishedd (establishe(establishedd iinn 19251925)) iiss superblsuperblyy together with the equippeequippedd witwithh UV/visiblUV Ivisiblee anandd FTIFTIRR proceeiingproceedingss ooff ou ourr spectrophotometersspectrophotometers, ^numerous X-ray organizationorganization,, brancbranchh unitunitss forfor ththee identificatioidentificationn ooff pearls pearls,^ anandd information, book reviews and abstracts. otheotherr sophisticatesophisticatedd identificatioidentificationn anandd Ad*Advertisements^ are accepted at very researcresearchh instrumentatioiinstrumentationL. reasonable rates. DIAMONDIAMONDD GRADINGRADINGG MEETI GS WWee alsalsoo offeroffer a DiamondDiamond GradingGrad^ facility •lyeptuteLectures ^by British and international wMewhichh iiss seconsecondd ttoo nonnonee in^ the world. experts are organized throughout the year BotBothh CIBJCIBJOO anandd GIGIAA reportreportss araree bbilMlboth in London^ and in the provinces. available.-available.- • - For further information on the services . ~:[;~~0$ " .:"'< . ~!;.~" "' '' ' availablavailablee pleaspleasee ususee ththee tear-oftear·offf couponcoupon; , ,,"~""" ... :.,- --." II^BMiSi IJStil provided or contact Mrs Laine Durkin on 071·404 3334 who will be pleased to assist you. 27 Greville Street, ..:r::;:: London ECIN 8SU -^ Telephone: 071·4043334 Fax:071-404884Fax: 071-40488433 364364 J.J. Gemm.Gemm.,, 1991,22,61991,22,6

SodiumSodium polytungstatpolytungstatee asas a gemmologicalgemmological tooltool W. William Hanneman, Ph.D.Ph.D.

CastroCastro ValleyValley,, CACA 94645,94645, USAUSA

CurrentlyCurrently,, thethe useuse ofof heavheavyy liquidliquidss iiss probablyprobably thethe liquiliquidd solution,solution, bothboth thethe stonestone anandd ththee stonestone tongstongs mostmost noxiousnoxious activityactivity ooff gemmologists.gemmologists. AsideAside fromfrom shouldshould bbee dippeddipped intintoo a containercontainer ofof rinserinse water.water. healthhealth factorsfactors,, thesethese liquidsliquids areare foufoull smellingsmelling andand AnAnyy 'lost'lost'' sodiumsodium polytungstatpoly tungstatee cancan bebe reclaimedreclaimed areare lighlightt sensitive.sensitive. TheyThey decomposdecomposee intintoo acidicacidic latelaterr bbyy simplysimply allowinallowingg thethe rinserinse waterwater ttoo evapoevapo and/oand/orr corrosivecorrosive productsproducts anandd thetheyy areare nonott reclaimreclaim- raterate.. ableable.. ThereThere oughtought toto bbee a betterbetter approachapproach - andand thertheree is.is. ItIt utilizeutilizess a substancesubstance knowknownn asas sodiumsodium RetrofittingRetrofitting heavlheavlyy liquiliquidd setssets polytungstatpoly tungstatee (Ref(Ref.. 1,2,3,4).1,2,3,4). TheThe simplestsimplest typetype ooff retrofiretrofitt forfor practisinpractisingg gemgem ! PurePure sodiumsodium polytungstatpoly tungstatee (3Na2(3Na2 W0W04•.9W09W0 44..- mologistmologists's (especiall(especiallyy thosthosee witwithh severaseverall setsetss ooff H 20)0) isis a whitewhite crystallinecrystalline powder.powder. ItIt isis notnot volatilevolatile bottlesbottles containincontainingg drieddried uupp and/oand/orr decomposeddecomposed andand hashas nnoo odourodour.. SodiumSodium polytungstatpoly tungstatee isis bothboth heavheavyy liquiliquidd solutions)solutions) isis ttoo cleacleann outout ththee ololdd bottlesbottles heatheat andand lightlight stable.stable. ItIt isis easileasilyy dissolvedissolvedd inin water,water, andand,, usingusing ththee samesame referencreferencee stones,stones, replacreplacee thethe easilyeasily rinsedrinsed fromfrom a gemgem,, anandd cacann bbee easileasilyy rere liquidsliquids witwithh appropriatappropriatee solutionssolutions ofof sodiumsodium polypoly claimed.claimed. ItIt isis non-reactive,non-reactive, anandd itsits solutionssolutions areare tungstatetungstate.. ThiThiss serviceservice iiss alsalsoo providedprovided bbyy HanneHanne neutral.neutral. manman GemologicalGemological Instruments.Instruments. SodiumSodium polytungstatpoly tungstatee isis availablavailablee inin smallsmall quanquan titietitiess aass a solutionsolution ofof 2.2.88 g/cmg/cm33 densitydensity foforr $12$12 perper DeterminationDetermination ooff densitdensityy usinusingg sodiumsodium ouncouncee fromfrom HannemanHanneman GemologicalGemological Instruments,Instruments, polytungstatpolytungstatee solutionssolutions EOP.O.. BoBoxx 24532453,, CastrCastroo Valley,Valley, CCAA 94546.94546. DensitiesDensities ThThee determinatiodeterminationn ofof ananyy densitdensityy belobeloww thethe valuevalue aass highhigh aass 3.13.1 g/g/cmcm3 araree easileasilyy preparedprepared.. A dropperdropper isis ooff 3.103.10 g/g/cmcm3 onon ananyy gemmologicagemmologicall specimenspecimen cacann bebe suppliedsupplied ttoo facilitatfacilitatee dilutions.dilutions. easileasilyy accomplishedaccomplished usinusingg sodiumsodium polypolytungstat tungstatee solutions.solutions. TheThe procedurproceduree startsstarts withwith a saturatedsaturated SafetySafety solutionsolution ooff sodiumsodium polytungstatpoly tungstatee oror oneone iinn whichwhich AAss iiss trutruee witwithh alalll substances,substances, thethe dosdosee makesmakes thethe ththee testestt specimenspecimen floatsfloats.. Then,Then, bbyy ththee carefulcareful poisonpoison.. Consequently,Consequently, nonott eveevenn watewaterr oorr oxygenoxygen cancan additioadditionn ooff watewaterr bbyy meanmeanss ofof a dropper,dropper, thethe densitydensity bbee guaranteedguaranteed toto bbee completelcompletelyy safe.safe. CurrentlyCurrently ooff ththee solutionsolution iiss reducereducedd toto ththee pointpoint aatt whicwhichh thethe thertheree iiss nono evidenceevidence atat alalll thathatt sodiumsodium polypolytungstat tungstatee specimenspecimen jusjustt remainremainss suspended.suspended. ThThee densitdensityy ooff causescauses healthealthh problemsproblems forfor itsits usersusers (Ref.(Ref. 2,4).2,4). ItIt ththee solutionsolution nownow matchematchess thatthat ofof ththee gemgem.. A dropdrop ooff produceproducess nono fumesfumes andand iiss notnot absorbedabsorbed bbyy ththee skin.skin. ththee liquiliquidd iiss thethenn removedremoved,, andand itsits refractiverefractive indexindex NeverthelessNevertheless,, oneone obviouslobviouslyy shouldshould nonott eateat it,it, andand (nD)(nD) iiss determineddetermined oonn anyany gemmologicagemmologicall refractorefracto- ononee shouldshould keepkeep iitt awayaway fromfrom childrenchildren.. IInn anyany casecase,, meter.meter. ThiThiss valuevalue isis comparecomparedd witwithh ththee graphgraph shownshown iinn allall aspectsaspects iitt iiss a vastvast improvementimprovement overover thethe inin FigureFigure 1I fromfrom whichwhich thethe densitydensity cancan bbee deter-deter organiorganicc brominbrominee compoundscompounds currentlcurrentlyy beinbeingg used.used. minedmined.. . AlternativelAlternativelyy ththee densitdensityy cacann bbee calculatecalculatedd bbyy UseUse ofof sodiumsodium polytungstatpolytungstate e solutionssolutions usinusingg thethe followinfollowingg equation:equation: GemmologistsGemmologists accustomeaccustomedd ttoo usingusing ththee traditiontradition 3 aall heavyheavy liquidsliquids shouldshould havhavee fewfew problemsproblems adjustingadjusting DensitDensityy (g/cm(g/cm3)) = 2.802.80 + 8.438.43 (nD(nD - 1.5551.555)) toto ththee useuse ooff sodiumsodium polytungstatpoly tungstatee solutions.solutions. TheyThey araree simplysimply a highighh concentrationconcentration ooff aann inorganicinorganic saltsalt NoteNotess oonn ththee useuse andand preparationpreparation ofof solutionssolutions dissolvedissolvedd inin waterwater.. Consequently,Consequently, ifif leftleft opeopenn ttoo thethe WhenWhen makinmakingg solutionssolutions ofof sodiumsodium polypolytungstate tungstate,, atmosphere,atmosphere, ththee watewaterr willwill evaporate,evaporate, leavinleavingg thethe onlyonly distilleddistilled,, deionized,deionized, oorr softenedsoftened watewaterr shouldshould whitewhite salt.salt. However,However, ththee solutionsolution cancan bbee easilyeasily bbee usedused.. TheThe presencpresencee ofof calciucalciumm ionionss willwill causecause thethe reconstitutedreconstituted bbyy replacingreplacing ththee water.water. formatioformationn ofof a finfinee whitwhitee precipitateprecipitate.. IfIf thisthis shouldshould WheneveWheneverr a gegemm iiss removeremovedd fromfrom thithiss heavyheavy happenhappen,, eitheeitherr ignoreignore iitt oror allowallow iitt ttoo settlesettle toto thethe

SodiumSodium polypolytungstattungstate e - waterwater solutionssolutions DensityDensity vsvs refractivrefractivee indexindex valuesvalues 1.6 ' 1.591.59 >/ /' 1.581,58 /'/ A 1,57 1.57 V / / OJ 1.56 / ."" .S ',/ OJ /' 1.551.55 'bu .;:oj v/ OJ 1.54 ~ // 1,53 ' 1.53 ,/ // 1,521.52 / // 1.51 //' T 1.5 2,4 2.6 2,8 3 DensityDensity ofof solution,solution, g/g/cmcm3

Fig.Fig. I.1. GraphGraph showingshowing thethe relationshiprelationship betweebetweenn refractiverefractive indexindex andand densitydensity ofof sodiumsodium polytungstatpoly tungstatee solutions.solutions. bottombottom andand removeremove it.it. tungstatetungstate solutionssolutions cannotcannot replacereplace purpuree methylenemethylene TheThe solubilitysolubility ofof thethe sodiumsodium polypolytungstat tungstatee inin iodideiodide (density(density 3.323.32 g/g/cmcm33).). BecauseBecause ofof itsits highhigh waterwater isis enhancedenhanced byby heat.heat. SupersaturatedSupersaturated solutionssolutions refractiverefractive indexindex (1.73),(1.73), methylenemethylene iodideiodide isis exex areare easilyeasily preparedprepared bbyy thethe additionaddition ofof solidsolid saltsalt toto a tremelytremely usefuluseful asas anan immersionimmersion liquidliquid forfor thethe warmedwarmed solution.solution. OnOn standingstanding overnight,overnight, crystalscrystals microscopicmicroscopic examinationexamination ofof thethe corundumcorundum gems.gems. willwill formform asas thethe supersaturatedsupersaturated solutionsolution becomesbecomes Consequently,Consequently, methylenemethylene iodideiodide probablprobablyy alwaysalways merelymerely saturated.saturated. TheThe densitydensity ofof thisthis solutionsolution isis willwill remainremain a vitavitall componentcomponent ofof thethe gemmologist'sgemmologist's 33 aboutabout 3.103.10 g/cm .• ProbablyProbably thethe besbestt wayway toto maintainmaintain arsenal.arsenal. AsAs such,such, itit willwill stillstill bebe availableavailable forfor densitydensity youryour sodiumsodium polypolytungstat tungstatee stockstock solutionsolution iiss asas a determinations.determinations. Fortunately,Fortunately, ofof allall thethe heavyheavy orgaorga saturatedsaturated solutionsolution withwith a fewfew crystalscrystals inin thethe bottom.bottom. nicnic liquids,liquids, methylenemethylene iodideiodide isis probablprobablyy thethe leastleast UnlikeUnlike organicorganic heavyheavy liquids,liquids, therethere isis onlyonly a noxious.noxious. minorminor changechange inin densitydensity whewhenn a warmwarm solutionsolution OnOn thethe otherother hand,hand, forfor thosethose workersworkers whowho wishwish toto cools.cools. SinceSince thethe refractiverefractive indexindex alsoalso changes,changes, therethere obviateobviate allall heavyheavy organicorganic liquidsliquids asas wellwell asas thethe isis a built-inbuilt-in temperaturetemperature compensation.compensation. AsAs a pracprac highlyhighly toxictoxic ClericiClerici Solution,Solution, thethe HannemanHanneman DirectDirect ticaltical matter,matter, asas longlong asas densitydensity valuesvalues areare expressedexpressed ReadingReading SpecificSpecific GravityGravity BalanceBalance (Ref.(Ref. 5)5) isis thethe toto onlyonly twotwo decimaldecimal places,places, thethe effectseffects ofof temperatempera mostmost cost-effectivecost-effective approach.approach. tureture cancan bebe neglected.neglected. SodiumSodium polytungstatpoly tungstatee cancan bebe reclaimedreclaimed fromfrom solutionssolutions atat anyany timetime bbyy allowingallowing thethe waterwater toto ReferencesReferences evaporate.evaporate. Overnight,Overnight, inin anan openopen vessel,vessel, willwill usuallyusually I.1. Callahan,Callahan, J.,J., 1987.1987. A Non·ToxicNon-Toxic HeavyHeavy LiquidLiquid …... ForFor bebe sufficient.sufficient. HeatHeat willwill accomplishaccomplish iitt inin a veryvery shortshort SeparationSeparation OfOf MineralMineral GrainsGrains,, Journal of SedimentarySedimentary time.time. ItIt isis notnot necessarynecessary toto gogo toto completecomplete dryness.dryness. PetrologyPetrology,, 57,4,765·6.57, 4, 765-6. NeverthelessNevertheless,, itit isis usuallyusually helpfulhelpful toto havehave a smallsmall 2.2. Kazantzis,Kazantzis, G.G. Handbook Of Toxicology Of Of Metals,Metals, Tungsten.Tungsten. InIn FribergFriberg et ai,al, Elsevier,Elsevier, NewNew York,York, 709709.. quantitquantityy ofof drydry saltsalt availableavailable forfor adjustingadjusting densitiesdensities 3.3. Savage,Savage, N.N.,, 1988.1988. TheThe UsUsee ofof SodiumSodium PolyPolytungstat tungstatee ForFor upward.upward. ThisThis isis simplersimpler thanthan evaporation.evaporation. ConodontConodont Separations,Separations. Journal of MicropalaeontologyMicropalaeontology,, 7,7, 1,1, AnyAny powderypowdery filmfilm ofof saltsalt remainingremaining onon a gem,gem, 39·40.39-40. tool,tool, oror refractometerrefractometer surfacesurface cancan bebe removedremoved byby 4.4. Sax,Sax, N.I.N.I.,, Lewis,Lewis, R.J.,R.J., 1986.1986. Rapid Guide To Hazardous Chemicals InIn The The Workplace. Workplace. Van Van Nostrand Nosirand Reinhold Reinhold Company, Com· wipingwiping withwith a softsoft dampdamp cloth.cloth. pany,New York. New 236.York. 236. 5.5. Anderson,Anderson, B.w.B.W. revisedrevised byby E.A.E.A. Jobbins,Jobbins, 1990.1990. Gem TestingTesting,, 10th10th Ed.,Ed., ButterworthsButterworths,, London,London, 6363.. DensitiesDensities aboveabove 3.13.1 g/cm3 FromFrom thethe precedingpreceding,, itit isis apparentapparent sodiumsodium poly-poly [Manuscript[Manuscript receivedreceived 24 24 SeptemberSeptember 1990.] 1990.] 366366 J.J. Gemm.,Gemm., 1991,22,61991, 22, 6

SpessartineSpessartine garnetgarnet inin BrazilianBrazilian topatopazz JohnJohn!. I. Koivula, C.C.W. W. Fryer and Robert. C. KammerlingKammerling

GemologicalGemological InstitutInstitutee ooff AmericaAmerica,, SantaSanta Monica,Monica, CaliforniaCalifornia,, USUSAA

FigFig.. I.1. TwoTwo ooff ththee sisixx topatopazz crystalscrystals examineexaminedd foforr thisthis reportreport.. TheThe largerlarger ofof ththee twtwoo measuremeasuress approximatelyapproximately 2244 millimetresmillimetres inin lengthlength.. NotNotee ththee orange-coloureorange-colouredd inclusioninclusion clearlclearlyy visiblevisible iinn thethe smallersmaller crystalcrystal.. Photograph by Robert Weldon.

AbstractAbstract centimetrecentimetress inin lengthlength.. HHee statedstated thatthat thetheyy hahadd beenbeen SpessartineSpessartine garnegarnett inclusionsinclusions werweree identifiedidentified inin topatopazz minedmined fromfrom a smallsmall graniticgranitic pegmatitpegmatitee neanearr ththee towntown crystalcrystalss fromfrom aann areaarea northnorth ooff TeofilTeofiloo OtoniOtoni inin MinasMinas GeraisGerais,, BrazilBrazil.. ThThee inclusioninclusionss werweree studiedstudied usinusingg a ooff PadrePadre ParaisoParaiso iinn MinasMinas GeraisGerais,, Brazil,Brazil, approxiapproxi combinationcombination ofof opticaopticall microscopymicroscopy anandd X-rayX-ray powdepowderr matelmatelyy 100100 kilometrekilometress northnorth ooff TeofilTe6filoo OtonOtonii onon diffractiondiffraction analysisanalysis.. highwahighwayy 116116.. OnOnee ooff thethe authorauthorss purchasepurchasedd sixsix ofof thesethese crystalscrystals IntroductioIntroductionn foforr examination;examination, twotwo ooff whicwhichh areare shownshown inin FigureFigure ThThee topaztopaz crystalscrystals examinedexamined foforr thisthis reportreport werewere 1.1. TheThe crystalcrystalss werweree soldsold onlonlyy aass topaz,topaz, anandd whilewhile obtaineobtainedd inin FebruaryFebruary 19901990 inin Tucson,Tucson, ArizonaArizona atat thethe somesome ooff themthem hahadd prominenprominentt eye-visibleye-visiblee mineralmineral annuaannuall gegemm andand mineraminerall show.show. NatalinNatalinoo EugeniEugenioo dede inclusioninclusionss ofof a slightlyslightly pinkish-brownispinkish-brownishh orangeorange OliveiraOliveira,, a BraziliaBraziliann mineraminerall dealerdealer fromfrom BeloBelo colourcolour,, nono mentiomentionn was madmadee ofof thethemm bbyy Mr.Mr. HorizontHorizontee hahadd a collectioncollection ooff approximatelyapproximately 4040 ooff Oliveira.Oliveira. ItIt waswas,, howeverhowever,, thesethese inclusionsinclusions thatthat thesethese crystalcrystalss rangingranging inin sizesize frofromm abouaboutt 1 toto 6 wherewhere ooff interesinterestt toto thethe authors.authors.

Fig. 2. Several well-defined spessartine garnets lie just be Fig. 3. The largest of the inclusions, a 1.7 millimetre spessar neath a prism face of their host topaz. Photomicrograph tine garnet exhibiting distinct isometric symmetry. by John I. Koivula. Magnified 5 x. Photomicrograph by John I. Koivula. Description and a tiny drop of refractometer contact liquid (RI The colour of the topaz crystals was a very pale 1.81) was placed on the fragment. When so im brownish-yellow, possibly resulting, at least in part, mersed the fragment virtually disappeared, show from the presence of brownish-yellow limonitic ing that the inclusion and the liquid were almost stains in surface-reaching pits and fractures. A identical in refractive index. Examination of the well-developed prismatic form, typical for topaz, inclusion with polarized light while immersed in the was common to all these crystals (Figure 1). The liquid proved it to be isotropic. terminations were a combination of pyramid faces Next, brightfield illumination was employed. and pinacoids, while the bases looked to be cleavage The microscope was critically focused on the planes modified by very light etching. fragment and the stage lowered, increasing its The inclusions in all of the topaz crystals were distance from the objective lens. This caused the confined to the near-surface area (Figure 2). They bright Becke line to move slightly outward into the showed a slightly pinkish brownish orange colour as liquid, proving that the liquid (1.81) had an index of previously mentioned, with a transparent to trans refraction higher than the inclusion. The results lucent diaphaneity. Initial examination with a gem- showed that the inclusion's refractive index was mological microscopic revealed an outward shape of within the range previously established for spessar the inclusions that suggested an isometric struc tine garnet (Liddicoat, 1989; Anderson, 1990). ture. While some of the inclusions exhibited dis torted forms, others showed obvious dodecahedral X-ray diffraction symmetry (Figure 3). The reported pegmatitic Using a glass fibre, a spindle was prepared for origin of the topaz hosts together with the generally X-ray powder diffraction from a minute amount of isometric appearance and colour of the inclusions, powder obtained by scraping one of the inclusions suggested that the inclusions might be spessartine exposed at the topaz crystal's surface. The spindle garnet. was mounted in a Debye-Scherrer powder camera As all of the inclusions were completely enclosed and exposed for 13 hours to X-rays generated from a by the host topaz it was decided that one of the copper target tube by a voltage of 46 kilovolts and a crystals would be broken in order to expose some of current of 26 milliamperes. Once exposed, the film the inclusions for analysis by optical microscopy was developed and allowed to air-dry. and X-ray diffraction. Because spessartine was initially suspect, the A rock and mineral splitter was therefore used to resulting pattern was first compared to our standard accomplish the task of exposing the inclusions for file pattern for this garnet. The result was a perfect further study. Once the topaz was broken one of the match, indicating structure very close to the (pure) largest inclusion fragments was removed from its spessartine end member. host and placed on a 3x1 inch glass slide for microscopic examination. The inclusions, still Conclusion attached to the freshly broken topaz surface, were Optical microscopy and X-ray diffraction were used set aside for X-ray powder diffraction analysis. to identify the euhedral to slightly distorted high- relief inclusions in these topaz crystals as spessar Optical microscopy tine garnets. The distinct shape and near-surface The inclusion fragment on the glass slide was entrapment of the inclusions are typical of late-stage centred on the stage of a Zeiss research microscope syngenetic growth. 368368 J.J. Gemm.,Gemm., 1991,22,61991, 22, 6

ThisThis isis notnot thethe firstfirst timetime thatthat spessartinespessartine garnetgarnet ReferencesReferences hashas beebeenn identifiedidentified asas anan inclusioninclusion iinn topaztopaz (Giibelin(Gubelin Anderson,Anderson, B.w.,B.W., 1990.1990. Gem Testing,Testing , TenthTenth EditionEdition revisedrevised E.A.E.A . andand Koivula,Koivula, 1986).1986). However,However, thisthis isis thethe firstfirst timetime JJobbins obbins.. Butterworths,Butterworths, London,London, England.England. Giibelin,Gübelin, E.J.,E.J., Koivula,Koivula, J.I.,J.I., 1986.1986. Photoatlas of InclusionsInclusions. in thatthat thethe authorsauthors havehave hahadd thethe opportunityopportunity toto Gemstones. ABCABC Edition,Edition, Ziirich,Zürich, Switzerland.Switzerland. examineexamine specimensspecimens thatthat areare soso locality-specific.locality-specific. Liddicoat,Liddicoat, R.T.,R.T., 1989.1989. Handbo~kHandbook of Gem Identification. 12th12th TopazTopaz andand spessartinespessartine garnetgarnet areare bothboth knownknown toto Edition,Edition, SecondSecond RevisedRevised Printing.Printing. GemologicalGemological InstituteInstitute ofof occuroccur inin complexcomplex graniticgranitic pegmatitepegmatitess (Roberts,(Roberts, America,America, SantaSanta MonicaMonica,, California.California. Roberts,Roberts, w.L., W.L., Campbell, Campbell, T.J., Rapp, Rapp, G.R., G.R., Jr., 1990.Jr., 1990. Encylopedia En CampbellCampbell andand Rapp,Rapp, 1990).1990). TheyThey areare sometimessometimes cylopediaof Minerals. of Second Minerals. edition. Second Van Nostrand edition. Van Nostrand foundfound asas well-formed,well-formed, gem-qualitygem-quality crystalscrystals inin thethe Reinhold,Reinhold, NeNeww York.York. core-zonecore-zone ofof thesethese pegmatitespegmatites,, inin 'gem'gem pockets'pockets' Shigley,Shigley, J.E.,J.E., Kampf,Kampf, A.R.,A.R., 1984.1984. Gem-BearingGem-Bearing Pegmatites:Pegmatites: a (Shigley(Shigley andand Kampf,Kampf, 1984).1984). WithinWithin thesthesee 'pockets''pockets' review.review. Gems&Gems & Gemology,Gemology, 20,20, 2,2, 64-77.64-77. topatopazz isis thethe moremore commoncommon ofof thethe twtwoo minerals.minerals. [[ManuscriptManuscript receivedreceived 2 2 November November 1990.]1990.] BecauseBecause ofof itsits chemistry,chemistry, topaztopaz cancan crystallizecrystallize latelate inin thethe developmentdevelopment ofof a 'pocket~'pocket', asas cancan spessartinespessartine forfor thethe samesame reason.reason. TheThe near-surfacenear-surface locationlocation ofof thethe spessartinespessartine inclusioninclusionss inin thesethese topaztopaz crystalscrystals indiindi catescates thatthat a singlesingle cyclecycle ofof garnetgarnet growthgrowth occurredoccurred nearnear thethe endend ofof thethe growthgrowth cyclecycle ofof thethe topaztopaz (James(James E.E. Shigley,Shigley, personal communication).communication). PORTABLEPORTABLE POLARISCOPEPOLARISCOPE

FromFrom thethe GemmologicalGemmological InstrumentsInstruments LtdLtd rangerange ofof equipment.equipment. TheThe RaynerRayner battery-operatedbattery-operated portableportable polariscopepolariscope;; basedbased onon thethe principlprinciplee ofof a Scopelight.Scopelight. SimplySimply insertinsert a gemstonegemstone intointo thethe polariscopepolariscope 'well','well', rotaterotate thethe filter,filter, andand viewview withwith easeease whetherwhether thethe gemstonegemstone isis singlysingly oror doublydoubly refractive.refractive. QuickQuick andand effortlesseffortless distinctiondistinction betweenbetween manymany gemgem species.species.

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Gemmological Abstracts

ARJALAGUER I VILARDELL, D., 1990. Abaco para Parisite is a well-known inclusion material of determination de los precios aproximados de los emerald. It is also found in Muzo in combination diamante s con talla brilliante de River a Top Cape with emerald, pyrites, marcasite, dolomite, albite, y para las purezas de Internally flawless a Pique calcite, quartz and gypsum. The authors examined en el intervalo de pesos de 0.25 a 3.00 quilates. a faceted specimen which was transparent and (Abacus for determining the approximate prices yellowish-brown. SG 4.33-4.34, RI 1.671-1.772, for brilliant-cut diamonds from River to Top DR 0.101, hardness 4-4V2. The stone showed a Cape and from clarity grades Internally Flawless distinct rare earth spectrum Nd3 + and Pr3 + E. S. to Pique with weight intervals from 0.25 to 3.00 ct.) Gemologia, 32, 85/86. 5-11,1 loose chart. An abacus [chart] is proposed for the determina BARTOLI, F., BITTENCOURT ROSA, D., DOIRISSE, tion of brilliant-cut diamond prices within certain M., MEYER, R., PHILIPPY, R., SAMAMA, J.-C, qualities and clarity grades. M. O'D. 1990. Role of aluminium in the structure of Brazilian opals. European Journal of Mineralogy, BANK, H., HENN, U., 1990. Kiinstlich gefarbte 2, 5,611-19,6 figs. Quarze als Imitationen fur Smaragd, Rubin und Major and trace element analyses by ICP of Saphir. (Artificially dyed quartzes as imitations precious opals from the State of Piaui, NE Brazil, for emeralds, rubies and sapphires.) Zeitschrift der show that the A1203 content appears to be the major Deutschen Gemmologischen Gesellschaft, 39, 2/3, control on the close-packed structure of silica 147-51, 7 figs (6 in colour), bibl. spheres, surface properties and colour. The Al-poor The raw materials for these imitations are trans opals (A1203 0.*6—1.*3 wt.%) are white-yellow to parent to translucent quartzes, i.e. rock crystal to dark yellow, relatively well ordered and associated milky quartz. Both rough crystals and cut stones with sandstones; their physically adsorbed water is have been examined by the authors. Cracks are lower (2. *6—3.*4 wt.%) than in Al-rich opals. In artificially induced, then the dye concentrates in contrast, the Al-rich opals (A1203 1.4—1.8 wt.%) these cracks, colouring them green, red or blue. and hydrated opals (physically adsorbed water According to CIBJO regulations these stones must 3.-8—4.*9 wt.%) present blue iridescence due to a be offered as artificially irreversible (or permanent less dense packing of silica spheres; they occur in ly) dyed agates. E.S. claystones. The IR, XRD and DTA patterns all show that the substitution of Al for Si in the BANK, H., HENN, U., 1990. Geschliffener, rosa- tetrahedral network is a function of the A1203 farbener Hodgkinsonit aus Franklin Furnace, content. R.A.H. New Jersey, USA. (Cut, pink hodgkinsonite from Franklin Furnace, New Jersey, USA.) Zeitschrift BECK, R.J., 1983. A new development in under der Deutschen Gemmologischen Gesellschaft, 39, 4, standing: the prehistoric usage of nephrite in 273-4, bibl. New Zealand. Bulletin of the Friends of Jade, 3, The authors describe the physical data of cut, 48-53, 5 figs. pink hodgkinsonite from Franklin Furnace in New After a general note on New Zealand nephrite, an Jersey. Hodgkinsonite is a silicate of the euclase- account is given of experiments to duplicate the hodgkinsonite group MnZn2[(OH)2Si04] and is appearance of prehistoric artefacts by heating. monoclinic-prismatic. SG 3.98, RI values nx = Hardness tests are also described. M.O'D. 1.720, ny= 1.739, nz= 1.743. DR0.023. E.S. BENTE, K., THUM, R., WANNEMACHER, J., 1991. BANK, H., HENN, U., PLATEN, H.V., 1990. Ges Colored pectolites, so-called 'Larimar' from Sier chliffener, durchsichtiger, gelbbrauner Parisit ra de Baoruco, Barahona Province, southern aus Muzo, Kolumbien. (Polished, transparent, Dominican Republic. Neues Jahrbuch fur Miner- yellowish-brown parisite from Muzo, Colombia.) alogie, Monatshefte, 1, 14-22, 2 figs. Zeitschrift der Deutschen Gemmologischen Gesell Pectolites from the Siera de Baoruco, Dominican schaft, 39,4, 229-32,1 graph, 1 table, bibl. Republic, are found in white to greenish and light 370 J. Gemm., 1991, 22, 6 bluish to blue colours. They form part of hydro ther CASSEDANNE, J., 1990. Un nouvel indice de microc- mal alteration products within a picritic basalt of line gemme a Minas Gerais. (A new variety of gem Cretaceous age. Formation temperature is thought microcline from Minas Gerais.) Revue de Gemmo to have been below 240°C. M.O'D. logie, 104,13-14, 6 figs (2 in colour). A hyaline variety of microcline is reported from BlANCHI PoTENZA, B., DE MlCHELE, V., LlBORIO, Fazenda Bel Vista, or Corrego do Luis, Minas G., NANA, G.P., 1989. L'olivina della Val Malenco Gerais, Brazil. The microcline occurs in a pegmatite (Sondrio) come materiale di interesse gemmolo- and has SG 2.57, H 6.5, and RI 1.518, 1.522 and gico. (Olivine from the Val Malenco (Sondrio) as 1.525 with a DR of 0.007. No absorption spectrum a material of gemmological interest.) La Gemmo- nor luminescence could be detected. Various inclu logia, 14, 3/4,23-33, 15 figs (12 in colour). sions are described. M.O'D. Green transparent olivine from the Giuel quarry in the Val Malenco, Sondrio, Italy, has SG 3.39, RI CASSEDANNE, J., 1990. Un nouveau materiau gem 1.661, 1.679, 1.699. Composition is close to 85.7 me: le quartzite a lazulite (Bahia-Bresil). (A new mol% forsterite, 14.0 mol% fayalite and 0.3 mol% gem material: lazulite in quartzite from Bahia, tephroite. Serpentine fibres and colourless diopside Brazil.) Revue de Gemmologie, 105,117-18, 3 figs crystals are found as inclusions. M.O'D. in colour. Gem quality translucent to opaque blue lazulite is BITTENCOURT, ROSA D., 1990. Les opales nobles reported from a quartzite in the north-west of the du District de Pedro II dans l'Etat de Piaui- state of Bahia, Brazil. The locality is between the Region Nord-Est du Bresil. (Precious opal from valleys of the Rio Paramirim in the east and the Sao the Pedro II district in the state of Piaui, north Francisco, in the west. Cabochons cut from the east Brazil.) Revue de Gemmologie, 104, 3-7, 14 lazulite have SG 2.76, RI 1.603-1.635 and 1.639- figs (3 in colour). 1.674. Stones appear a greyish-maroon through the Precious opal is reported from the Pedro II colour filter. Neither luminescence nor a useful district of Piaui state, north-east Brazil. The opals absorption spectrum were observed. M. O'D. have a comparatively low water content and should be stable. Quality is said to be good. M.O'D. CASSEDANNE, J.P., ALVES, J., 1990. Crystallized rose quartz from Alto da Pitora, Minas Gerais, BLANKENSHIP, D.T., 1985. The toughness of Brazil. Mineralogical Record, 21, 5, 409-12, 7 figs nephrite. Bulletin of the Friends of Jade, 4, 56-60. (6 in colour). The toughness of nephrite is discussed with Fine crystallized rose quartz is reported from particular reference to modern lapidary methods. Lavra [mine] da Pitora, on the northern slope of the M.O'D. Serra da Piorra range, 8km east north east of Galilea, BLEIKER, R., 1991. Die beruhmte chilenische Minas Gerais, Brazil. The quartz occurs in radiating Lapis-Lazuli-Lagerstatte bei Ovalle, Region Co- clusters, in groups of parallel to subparallel prisms quimbo. (The famous Chilean lapis-lazuli loca and as isolated crystals. M.O'D. tion near Ovalle, Coquimbo region.) Lapis, 16, 1, 18-23,10 figs (8 in colour). CHENG, TE-K'UN, 1985. Chinese jade exhibition, Lapis-lazuli is found in Chile near Ovalle in the Chengtu 1945. Bulletin of the Friends of Jade, 4, Coquimbo region on the border with Argentina. 61-6. Geological details of the occurrence are given. An introduction to Chinese jade in general M.O'D. precedes details of a jade exhibition held in Chengtu in 1945. Chinese characters for the basic jade BOSSHART, G., 1990. Les emeraudes de Colombie. artefact shapes are given. M. O'D. (Colombian emeralds.) Revue de Gemmologie, 105,13-16,1 fig. in colour. CHIHARA, K., 1989. (JADEITE IN GUATEMALA.) The paper introduces the history of Colombian Journal of the Gemmological Society of Japan, 14, emerald mining and goes on to describe the geogra 1/4, 26-35,10 figs. (In Japanese.) phy of the mine sites. Emerald formation and Geology, petrology, mineralogy and usage of properties are discussed and there are notes on Guatemalan jadeite are discussed. M. O'D. exploitation. M.O'D. COENRAADS, R.R., 1990. Key areas for alluvial BROWN, G., 1985. Detecting dyed jadeite. Bulletin diamond and sapphire exploration in the New of the Friends of Jade, 4, 28-32, 1 fig. England gem fields, New South Wales, Australia. Standard gemmological tests for jadeite are out Economic Geology, 85, 1186-207,19 figs. lined. M.O'D. At least two distinct periods of volcanic activity J. Gemm., 1991, 22, 6 371

are recorded for the Tertiary Central volcanic DE MICHELE, V., 1988. Kamienie szachetne i province which includes the New England gem ozdobne wloch. (Gem materials of Italy.) Miner fields of New South Wales, Australia. These define alogia Polonica, 19, 2, 127-36, 1 fig. key areas for diamond and sapphire exploration. Translation of a paper first appearing in La Other gem minerals found with sapphire include Gemmologia, 7,3/4,17-25,1981. M.O'D. zircon, rare chrysoberyl and chrome spinel in the placer deposits and in nearby basaltic soils olivine DIEHL, R., MENG, K.H., 1990. Ein gravierter and enstatite have been found. M. O'D. Kashmir-saphir. (An engraved Kashmir sap phire.) Zeitschrift der Deutschen Gemmologischen CONKLIN, L.H., 1990. The Harvard diamond Gesellschaft, 39, 4, 193-200, 7 figs (1 in colour), crystal. Matrix, 1, 6,90-2, 3 figs (1 in colour). bibl. A yellow diamond crystal weighing 84 ct and of The sapphire weighed 6.175 ct and measured octahedral form was stolen from the Harvard 12.19 x 10.04 x 5.32 mm, antique cut. 32 crown mineral museum in 1962. The history of the crystal facets and 4x16 facets on pavilion. Thin girdle. Silk is given. M.O'D. and microscopic inclusions showed it to be of Kashmir origin. The engraving represents a lion CORONA-ESQUIVEL, R., BENAVIDES-MUNOZ, sitting on a crown. The sapphire was found to have M.E., 1989. Excursion de la Sociedad Mexicana been engraved with fine diamond points using de Mineralogia a las minas de opalo del Estado de non-rotating tools. Due to the complexity of the Queretaro. (Excursion to the Queretaro opal motif, the documents thus sealed could not be mines by the Sociedad Mexicana de Mineralo forged. It is assumed that the seal was used by an gia.) Boletin de Mineralogia, 4,1, 80-5, 3 figs. Indian ruling family, probably Sikh, but origin and Details of the opal mines in the Mexican state of age are not known, although this sapphire has been Queretaro are given with notes on the geology and used frequently as an official seal. E. S. mineralogy. The most important of the mines are La Carbonera and Santa Maria Iris, both north of the FERREIRA, J.A.M., KARFUNKEL, J., SILVA, L.T., town of San Juan del Rio. M.O'D. 1990. Turmaline mit ungewohnlich intensiven Farben von Salgadinho, Paraiba, Brasilien. COZAR, J.S., 1989. Determination de rasgos de (Tourmalines with exceptionally intensive col tratamiento, en topacios azules irradiados, por ours from Salgadinho, Paraiba, Brazil.) Zeitschrift espectroscopia gamma de alta resolution. (Deter der Deutschen Gemmologischen Gesellschaft, 39, mination of signs of treatment in irradiated blue 2/3,165-7, bibl. topaz by gamma-ray spectroscopy. )Boletin del This new find in Paraiba in the north east of Instituto Gemologico Espahol, 31, 8-18, 14 figs( 8 Brazil consists of four small occurrences in Salga in colour). dinho. The tourmaline crystals are up to one metre Gamma-ray spectroscopy is ruled to be the only in length, but internally flawed due to tectonic method of distinguishing natural from irradiated movements. The cuttable stones are therefore re blue topaz. M.O'D. latively small. Colours are particularly intense and occur as emerald green to red, aquamarine-blue to violet. Multi-coloured stones are no exception. COZAR, J.S., SARMIENTO, L., BARBOSA, J.E., 1990. Some physical and chemical data are added. E. S. Trifllita gema. (Triphylite as a gemstone.) Boletin del Instituto Gemologico Espahol, 32, 31-6, 14 figs FLINT, D.J., DUBOWSKI, E.A., OLLIVER, J.G., (7 in colour). 1985. Latest report on Cowell jade. Bulletin of the Orange-brown triphylite from Minas Gerais, Friends of Jade, 4, 82-5. Brazil, has SG 3.51, RI 1.689,1.693,1.698 with DR More than one hundred outcrops of nephrite 0.007. M.O'D. have been found since 1966 in the Cowell area of the Eyre Peninsula, South Australia. Country rocks are CURRAN, R.T., 1988. A Hamlin Mount Mica quartzo-feldspathic gneiss and dolomitic marble. tourmaline. Matrix, 1, 5, 77-8, 2 figs. M.O'D. A crystal from the collection of the Hamlin family has come to light in the author's collection. A cavity FREY, R., 1983. Jade in Korea. Bulletin of the at Mount Mica was opened by Augustus C. Hamlin Friends of Jade, 3, 66-69,4 figs. in 1868 although the first tourmaline discoveries in Several colours of nephrite are found in Korea, a the area date back to the 1820s. The crystal large deposit of white-to-cream material being measures V/s inches in length and weighs approx particularly valuable. This occurs at the Chuncheon imately 60 ct. The colour is fine blue-green. M.O'D. mine situated near the city of the same name, about 372 J. Gemm., 1991, 22, 6

70 km north-east of Seoul. M. O'D. 16, 2, 37-46,20 figs (14 in colour). Emerald has been found on the Kesselklamm in FRIESE, B., 1991. Morphologie und Entstehung der the Austrian Untersulzbachtal. The area is south Sternsaphire aus Zaire. (Morphology and origin east of Neukirchen and the emeralds, some crystals of star sapphires from Zaire.) Aufschluss, 42, of which reach 7 mm in length, occur in a biotite 47-52,11 figs (10 in colour). schist. M.O'D. Star sapphire with a yellowish-brown back ground and a dark star is reported from Zaire. HANNI, H.A., 1990. Les gemmes du groupe des M.OT>. beryls. (Gemstones of the beryl group.) Revue de Gemmologie, 104, 8-12, 8 figs in colour. FUERTES MARCUELLO, J., GARCIA GUINEA, J., Gemstones of the beryl group are described and 1990. Caracterizacion mineralogica e historica del some notable specimens illustrated. M.O'D. larimar de Barahona (Republica Dominicana). (Mineral characteristics and history of larimar HANNI, H. A., 1990. Ein Beitrag zu den Erkennung- from Barahona, Dominican Republic.) Boletin del smerkmalen der Kaschmir-Saphire. (A contribu Instituto Gemologico Espahol, 32, 6-12, 11 figs in tion to the determination of Kashmir sapphires.) colour. Zeitschrift der Deutschen Gemmologischen Gesell- The ornamental blue variety of pectolite, larimar, schaft, 39, 2/3, 107-20, 21 figs (9 in colour), bibl. is found at Barahona in the Dominican Republic. More than fifty cut Kashmir sapphires were Characteristics and mining history are given. investigated. The detected inclusions confirmed M.O'D. those previously described in literature. Those specifically examined were tourmaline, pargasite, GRICE, J.D., BOXER, G.L., 1990. Diamonds from zircon, plagioclase, uraninite, allanite and probably Kimberley, Western Australia. Mineralogical Re rutile. Specific healing fissures and growth charac cord, 21, 6, 550-64, 9 figs (3 in colour). teristics and spectral peculiarities are discussed. The Argyle AK1 mine is producing the largest E.S. number of diamonds in the world at the time of writing. Pink stones are conspicuous in the produc HEMRICH, G.L., 1983. The jade work of India. tion and 'cognac', yellow 'champagne', apricot, Bulletin of the Friends of Jade, 3, 54-7. green and blue stones are also found. M. O'D. The article discusses the origin of the jade pieces in the collection of the Moguls. Afghanistan is GROAT, L.A., RAUDSEPP, M., HAWTHORNE, F.C., suggested as a place of origin for some of the pieces. ERCIT, T.S., SHERRIFF, B.L., HARTMAN, J.S., M.O'D. 1990. The amblygonite-montebrasite series: characterization by single-crystal structure re HENN, U., 1990. Cordierit aus Sud-Norwegen. finement, infrared spectroscopy and multinuc- (Cordierite from south Norway.) Zeitschrift der lear MAS-NMR spectroscopy. American Miner Deutschen Gemmologischen Gesellschaft, 39, 2/3, alogist, 75,992-1008, 9 figs. 99-106, 5 figs (4 in colour), 1 table, bibl. The F = OH substitution in the amblygonite- The cordierite occurrence in south Norway lies a montebrasite series is referred to a battery of tests. few kilometres away from Kragero, in an aventur- M.O'D. ine-feldspar-rich pegmatite layer surrounded by Precambrian para-gneiss and amphibolitic zones. GRUBESSI, O., AURISICCHIO, C., CASTIGLIONI, A., RI 1.532-1.534 to 1.537-1.540, DR 0.010-0.012. SG 1989. Lo smeraldo delle miniere dei faroni. 2.55-2.57. The pleochroic colours are blue, bluish- (Emerald mines of the Pharaohs.) La Gemmolo- violet and yellow, caused by iron. The spectrum gia, 14, 1/22, 7-21,9 figs (5 in colour). shows two bands at 936 and 573 nm, caused by iron. Emeralds found in a quartz and mica schist with There are hematite platelet inclusions causing the phlogopite, plagioclase and calcite at Djebel Zabar- aventurism and/or a cat's-eye effect. E. S. ah, Egypt, are thought to be similar to stones used in early Egyption jewellery. They are akin to Habach- HENN, U., BANK, H., 1990. Uber die Farbe der tal stones in properties and appearance. M. O'D. Sodalith-Minerale: Sodalith, Lasurit (Lapis lazu li) und Hauyn. (About the colour of the sodalite GRUNDMANN, G., SCHAFER, W., HOFER, H., 1991. minerals: sodalite, lazurite (lapis-lazuli) and Smaragde aus der Kesselklamm, eine interes- hauyne.) Zeitschrift der Deutschen Gemmologischen sante Neuentdeckung im Untersulzbachtal. Gesellschaft, 39,2/3,159-63,1 table, 1 graph, bibl. (Emerald from the Kesselklamm, an interesting The article summarizes the causes of colour in new discovery in the Untersulzbachtal.) Lapis, minerals of the sodalite group. Colour centres are J. Gemm., 1991, 22, 6 373

responsible forthe colour. The blue colour is caused KAMMERLING, R.C., KOIVULA, J.I., 1990. An by S03" or O centres, while sulphur complexes investigation of a dyed quartzite resembling like S04" or SO3" and S3~ or S2~ are responsible for sugilite. South African Gemmologist, 4, 3, 20-7, 3 the blue colour in lazurite and hauyne. S2~ centres figs in colour. are the reason for the orange-red luminescence. E. S. A dyed quartzite was confused with manganoan sugilite from the Wessels Mine near Kuruman, HENN, U., BANK, H., BANK-SCHERNER, M., 1990. South Africa. The colouring is seen to be concen Rubine aus dem Pamir-Gebirge, UdSSR. trated in fractures. M.O'D. (Rubies from the Pamir mountains, USSR.) Zeitschrift der Deutschen Gemmologischen Gesell- KATO, M., 1989. (Nomograph for calculating facet schaft, 39,4, 201-5,6 figs (1 in colour), bibl. cutting angles.) Journal of the Gemmological Soci The cuttable rubies originate in a marble zone of ety of japan, 14,1/4,12-15,4 figs. (In Japanese.) the Pamir mountains in the USSR near to the Nomographs are presented for the purpose of Chinese border. The red, reddish, and violet-red evaluation of facet cutting angles. M.O'D. stones have an SG 3.98, RI Ne = 1.761-1.762, n0 = 1.769-1.770, DR 0.008. Under the microscope one KATO, M., 1989. (Nomographs for diamond inci can see twinning lamellae, healing cracks, fluid dence-radiation.) Journal of the Gemmological inclusions, rutile dust and distinct growth striae. Society of Japan, 14, 1/4, 16-20, 4 figs. (In Trace elements were found to be chromium, iron Japanese.) and titanium. The absorption spectra showed typic Four nomographs are presented to illustrate the al Cr bands and the fluorescence is strong red. E. S. elucidation of scintillation in diamond. M. O'D.

HUNSTIGER, C, 1990. Darstellung und Vergleich KATO, M., 1989. (Nomographs of diamond inci primarer Rubinvorkommen in metamorphen dence-radiation on a pavilion.) Journal of the Muttergesteinen. Petrographie und Phasenpetro- Gemmological Society of Japan, 14, 1/4, 21-5, 4 logie. Teil III. (Presentation and comparison of figs. (In Japanese.) primary ruby occurrences in metamorphic rock. Nomographs are used to illustrate the passage of Petrography and phase petrography. Part III.) light through the pavilion of diamond. M. O'D. Zeitschrift der Deutschen Gemmologischen Gesell- schaft, 39, 2/3, 121-45, 7 figs (4 in colour), 3 KATO, M., 1988. (The scintillation by the incident tables, extensive bibl. rays through the pavilion.) Journal of the Gemmo Part III of this article deals with the formation of logical Society of Japan, 13,1/4,13-19,15 figs. (In rubies in marble, in more detail with the occurr Japanese.) ences in Prilep in Macedonia, where the rubies of The paper discusses how to counteract loss of irregular shape occur in white marble. The corun some of the incident rays through the pavilion of dum found in Passo Campolungo/Passo Cadonighi- gemstones. M.O'D. no in Switzerland is found as ruby as well as sapphire. Other ruby-carrying marbles mentioned KATO, M., 1988. (Incidence-radiation relations are those in Stirigma in Greece and those in Hunza, between the incident rays through the pavilion.) Kashmir. The petrology of rubies in marbles and Journal of the Gemmological Society of Japan, 13, dolomites is discussed. Further occurrences de 1/4, 22-4, 5 figs. (In Japanese.) scribed are those in Mangari in Kenya, in kyanite, Five examples of gemstone cutting are discussed tourmaline and feldspar rock, those found in Ngor- with particular reference to the behaviour of rays ongoro in Tanzania, found in anatextite, as well as passing to and through the pavilion. M.O'D. finds in O'Briens Claim, Zimbabwe, Mashishimala in South Africa, three mines in Madagascar (Vato- KEVERNE, R., 1983. A worldwide view of the jade mandry, Ankaratra and Gogogogo) and finally those market. Bulletin of the Friends of Jade, 3,14-21. in Malawi. In the majority of cases the rubies seem Sale-room prices for notable jade artefacts are to be a decomposition product. E. S. given: the year represented an improvement on previous market performance. M.O'D. KAMMERLING, R.C., KOIVULA, J.I., 1990. An update on assembled emerald specimens from KINNUNEN, K.A., MALISA, E.J., 1990. Gem- Africa. South African Gemmologist, 4, 3, 9-15, 4 quality chrysoprase from Haneti-Itiso area, cen figs in colour. tral Tanzania. Bulletin of the Geological Survey of Supposed emerald crystals from Zambia turned Finland, 62, 2,157-66. out to be colourless quartz fragments cemented Gem-quality, apple-green, Ni-bearing chalcedo- with a green epoxy-like material. M. O'D. nic silica occurs as veins in silicified serpentine in 374 J. Gemm., 1991, 22, 6 the Haneti-Itiso area. AAS gave high Ni 0.55 wt.% layer on the surface of pearls. Incidence can be and low Co and Cr (120 and lppm, respectively); lowered by keeping specimens in low or constant NAA revealed near chondritic REE contents. XRD humidity conditions. M. O'D. showed that the chrysoprase consists mainly of a-quartz and some opal-CT. The chrysoprase has LARSSON, T., 1990. Varmebehandlade bla safirer. RI 1.548-1.553, mean SG 2.56. Microscopically the (Heated blue sapphire.) Gem Bulletin, 2,4-7. Tanzanian chrysoprase consists of spherules which Details of the heat treatment of blue sapphire are are highly disordered, concentric, and composed of given with a short list of references. M. O'D. bipyramidal quartz, chalcedony, quartzine and opal-A. They can be classified into four main types LEAMING, S., 1983. On the origin of jade. Bulletin of according to the arrangement of concentric shells. the Friends of Jade, 3, 30-4. The diameter of the spherules ranged from 40 to 77 The crystal structure and chemical composition jum. Fluid inclusion types in the bipyramidal quartz of the jade minerals are discussed. M.O'D. are single phase, low-T type. The spherules, silica types and REE contents suggest that this chrysop LEUNG, I.S., 1990. Silicon carbide cluster entrap rase was deposited by evaporation of surface waters ped in a diamond from Fuian, China. American connected with the silicification of the serpenti- Mineralogist, 75, 1110-19, 7 figs. nites. R.A.H. A diamond crystal from Fuian, China, was found to contain four bluish-green 6H silicon carbide KIDWELL, A.L., 1990. Famous mineral localities: crystals overgrown by grains of the 3C polytype. Murfreesboro, Arkansas. Mineralogical Record, The multicrystalline cluster is surrounded by a thin 21, 6, 545-55, 14 figs (3 in colour). layer of K-Al-Si-rich glass in which an iron-rich The area is the largest and best-known diamond spherule is embedded. It appears that cubic SiC is a producer in the United States and forms part of the distinct though unnamed mineral species. M. O'D. Prairie Creek intrusive, about 3.5 km south-east of Murfreesboro, Pike County, south-west Arkansas. LHOEST, J.J., GAUTHIER, G.J., KING, V.T., 1991. Diamond crystals are recovered from several diffe The Mashamba West mine, Shaba, Zaire. Miner rent places in the area where they occur randomly. alogical Record, 22, 1, 13-20, 19 figs (13 in Their origin is at present unknown. M.O'D. colour). Among the minerals found at this copper mine KOIVULA, J.I., FRYER, C.W., 1990. Forsterite in are cobaltian calcite and transparent cuprite. Both Arizona pyrope. Zeitschrift derDeutschen Gemmo- are of gem quality. M.O'D. logischen Gesellschaft, 39,4,207-9,5 figs in colour, bibl. LINTON, T., 1990. Lighting techniques for micro Some Arizona pyropes were examined by X-rays scopic observation. Wahroongai News, 24,6,24-7, and under the microscope. Forsterite was identified 6 line drawings. as the inclusion. Pyrope is also a common inclusions A useful paper on illumination and use of a in peridot (which is olivine of forsteritic composi polarizing microscope. R. K. M. tion). E.S. LOWE, E.J., 1983. The jade dilemma of the 1980s. KOIVULA, J.I., KAMMERLING, R.C., FRYER, C.W., Bulletin of the Friends of Jade, 3,22-9. 1990. Gormanite in quartz. Zeitschrift der Deuts The general charactistics of jadeite and nephrite chen Gemmologischen Gesellschaft, 39, 2/3, 153-7, are discussed with notes on the main sources and a 3 figs in colour, bibl. short bibliography. M.O'D. Crystal inclusions of a dark bluish-green stalk like birefringent mineral in a rough grouping of MCCOLL, D., PETERSON, O.V., 1990. Titanite quartz crystals are described and identified, at least crystals from the Harts Range, Central Australia. in part, as gormanite (an iron aluminium phos Mineralogical Record, 21, 6, 571-4, 7 figs (5 in phate) by means of X-ray diffraction and optical colour). microscopy. The host quartz was collected from the Gem quality crystals of sphene [titanite] are Yukon territory in north-west Canada. E. S. reported from a feldspathic vein in the Harts Range of Central Australia, 200km north-east of Alice KOMATSU, H., 1989. (Origin and a counterplan of Springs. M.O'D. 'Uroko' (scaly spot) on the surface of pearls.) Journal of the Gemmological Society of Japan, 14, MACKENZIE, R.W.K., 1990. An additional use for 1/4, 3-11,19 figs. (In Japanese.) the Eikhorst [sic] Thermolyzer. South African Scaly spot is a local deterioration of the nacreous Gemmologist, 4, 3,28-31. J. Gemm., 1991, 22, 6 375

The Eickhorst Thermolyzer is used to disting ly for X> 684.5nm reaching the value y= 70% in the uish diamond from its simulants. It can also be used region of k which responds in the deep red. There is to say what these simulants are. A thermal conduc a minor maximum at XQ= 578.7nm. M.O'D. tivity table of gem materials is appended. M. O'D. PLASZYNSKA, M., 1988. Niektore wspolczesne MEYER, A.B., 1985. The nephrite question 1888. metody badan kamieni szlachetnych. (New Bulletin of the Friends of Jade, 4,20-7. methods in gem testing.) Mineralogia Polonica, Theories on the origin of jade artefacts found in 19, 1,131-6,2 figs. America are advanced. It is believed that the pieces The paper describes the Ceres Diamond Probe originated in Asia but the article challenges this and the Gem Diamond Pen. A useful short biblogra- theory on the grounds of as yet unlocated deposits phy is appended. M.O'D. in Mexico and near the Amazon River. M.O'D. PONAHLO, J., 1990. Kathodolumineszenz-und M.G.C., 1985. Jade auction in Burma, 1979. Bulle Absorptionsspektren gelber Saphire. (Cathodo- tin of the Friends of Jade, 4, 67-80. luminescence and absorption spectra of yellow The paper consists largely of a reproduction of a sapphires.) Zeitschrift der Deutschen Gemmologis- catalogue of gems, jade and pearl issued by the chen Gesellschaft, 39,4, 225-8,2 figs, bibl. Myanmar [Burma] Gems Corporation in 1979. A microspectrophotometric method is proposed M.O'D. based on cathodoluminescence spectra to diffe rentiate between yellow, yellow-brownish and MIYATA, T., 1988. (An introduction to gem mines orange sapphires coloured by Cr and Fe from of Pakistan.) Journal of the Gemmological Society similar sapphires with different colouring agents. of Japan, 13,1/4, 31-42,20 figs. (In Japanese.) E.S. The gem production of Pakistan is discussed with a map of general deposits and a smaller scale map of QUELLMALZ, W., 1991. Die edlen Steine Sachsens. the Hunza ruby mines. M. O'D. (Gemstones of Saxony.) Lapis, 16,1, 24-35, 8 figs in colour. NAITO, Y., 1988. (Gem-grade chromian diopside Gem and ornamental minerals from Saxony, found in the upper stream of Sano River, Yama- Germany, are briefly described with notes on the nashi Prefecture.) Journal of the Gemmological whereabouts of notable specimens. M. O'D. Society of Japan, 13, 1/4, 25-30, 9 figs. (In Japanese.) QUELLMALZ, W., 1990. A brief look at the Saxon Large single crystals of emerald-green chrome Erzgebirge. Mineralogical Record, 21, 6, 565-70, diopside are reported from the upper stream of the 10 figs (6 in colour). Sano River in the Kamisano area of Yamanashi Among the minerals found in the Erzgebirge (ore Prefecture, central Japan. Crystals up to 2 cm in mountains) area of Saxony, Germany, are yellow length have been found. M.O'D. topaz from Schneckenstein, violet crystals from Greifenstein, honey-yellow baryte crystals from NICHOL, B., 1983. Nephrite jade deposits near Poehla near Schwarzenberg and several occurrences Cowell. Bulletin of the Friends of Jade, 3, 77-88, 5 of native silver. Gem quality quartz crystals are figs. found at Ehrenfriesdorf (rock crystal); amethyst is Nephrite is found associated with an isoclinally found at Wiesenbad near Annaberg and smoky folded dolomitic marble and calc-silicate rock hori quartz at Zinnwald. M.O'D. zon in the upper 'Gneiss' complex of the Cleve Metamorphics (Lower Proterozoic) near Cowell, Eyre Peninsula, South Australia. Colours are green RAMSEYER, K., MULLIS, J., 1990. Factors influenc ish-yellow and green and vary from pale tones to ing short-lived blue cathodoluminescence of black with increasing iron content. Fine-grained alpha-quartz. American Mineralogist, 75,791-800, black nephrite is the most valuable. M.O'D. 19 figs (16 in colour). Crystals of alpha quartz from the Swiss Alps and PLASZYNSKA, M., 1988. Measurement of transmis from Grand Canary showed a short-lived blue, sion of Chelsea filter. Mineralogia Polonica, 19, 1, bluish-green or yellow luminescence with some 113-15,1 fig. areas remaining inert. A longer-lived violet and a The transmission curve for the Chelsea filter is brown luminescence of increasing intensity are less examined using a spectrophotometer. The distinc often seen in alpha quartz. The phenomenon is tive transmission characteristic equals zero at 333- ascribed to the uptake of charge balancing single 361.4nm and 607.7-684.5nm and increases distinct charged cations associated with the substitution of 376 J. Gemm., 1991, 22, 6

Al for silica. H can also cause short-lived cathodolu- from the Jos region of Nigeria. From the area of minescence. M.O'D. Pereval, Lake Baikal, USSR, come pale pink octahedra of spinel in white marble. M.O'D. REDMANN, M., 1990. Changierender Fluorit aus dem Schwarzwald. (Colour-changing fluorite ROSENZWEIG, A., 1983. On the 'rind' of nephrite from the Black Forest.) Zeitschrift der Deutschen jade. Bulletin of the Friends of Jade, 3, 70-1. Gemmologischen Gesellschaft, 39, 2/3, 169-72, 1 The brownish coating of many nephrite pebbles graph, bibl. has been attributed to weathering but the author The colour-changing fluorite was found in the suggests that in some cases at least the effect may be Clara Mine near Wolfach in the Black Forest. The a consequence of inherent colour zoning. M. O'D. Clara Mine yields mainly barytes and fluorites but also many rare minerals. The fluorites are usually ROSENZWEIG, D., 1983. Flowers in Chinese jade colourless or blue, violet, green, yellow or pink. The carving. Part 1. Bulletin of the Friends of Jade, 3, colour-changing stone was deep blue in daylight 37-44,4 figs. and violet in artificial light. RI 1.434, SG 3.18. The Flowers are a common Chinese jade decoration absorption spectrum contains bands with maxima and are found particularly on Qing (1644-1911) 3+ at 580, 400, 335 and 225nm, caused by a Fm pieces. Flowers are commonly grouped into sets colour centre. Absorption minimum in the visible (e.g. the four noble plants, plum, chrysanthemum, range is located at 480nm. E. S. bamboo and orchid). M. O'D.

ROBERT, D., 1990. Mesure de couleur au micro SCHAFER, W., 1990. Belmont und Sta. Terezinha. scope. (Colour measurement with the micro Reise zu den brasilianischen Smaragdminen. scope.) Revue de Gemmologie, 105,19-20,4 figs in (Belmont and Sta Terezinha. Journey to the colour. Brazilian emerald mines.) Lapis, 15,11,13-26,29 A means of assessing colour values using the figs (23 in colour). microscope is outlined. M. O'D. The paper describes a visit to the Belmont and Santa Terezinha emerald mines in the state of Goias, ROBINSON, G.W., 1990. Famous mineral localities: Brazil. Crystals are found in various matrices, De Kalb, New York. Mineralogical Record, 21, 6, including quartz and biotite on the one hand and 535-41,13 figs (6 in colour). yellowish feldspar or dolomite on the other. Details Some of the green transparent diopside crystals of marketing are given. A table lists the constants from De Kalb, New York, are of gem quality. They for the Itabira [Belmont] and Santa Terezinha are found in Precambrian metasedimentary rocks of emeralds. M.O'D. the Grenville series and are retrieved from a north- trending ridge of interbedded quartzite and calcite SCHLUESSEL, R., 1990. Les saphirs de Bo Ploi rock. Their matrix ranges from a quartz-tremolite (Kanchanaburi-Thailande). (The sapphires of Bo schist to a nearly pure white massive diopside. Ploi, Kanchanaburi, Thailand!) Revue de Gem Crystal habits vary from simple to fairly complex, mologie, 105, 6-10,20 figs (6 in colour). the green colour being pale on the whole. M. O'D. Geology and gemmology of blue sapphires found at Bo Ploi, Thailand, are described together with ROBINSON, G.W., KING, V.T., 1990. What's new in notes on handling, cutting and marketing. The minerals? Mineralogical Record, 21, 5, 481-92, 10 sapphires are a dark to medium blue, have refractive figs (9 in colour). indices 1.761-1.769, DR 0.008 and SG 4.0. Plagioc- Among the minerals described are pale morga- lase crystals, acicular rutile and some multi-phase nite from Pala, California; very fine bi-coloured inclusions showing interference colours are among elbaite from the Himalaya Mine at Mesa Grande, the inclusions reported. M.O'D. California, and morganite crystals on albite from the White Queen Mine in the same state. Gem SCHWARZ, D., 1990. Die chemischen Eigenschaften quality fire opal is reported from Sabine Parish, der Smaragde. I. Brasilien. (The chemical prop near Toledo Bend Reservoir, Louisiana. Fine erties of emeralds. Part I. Brazil.) Zeitschrift der morganite is reported from the Bennett Mine, Deutschen Gemmologischen Gesellschaft, 39, 4, Buckfield, Maine. Lettuce-green gem quality spo- 233-72, 1 map, 14 graphs, 15 tables, extensive dumene is reported from Resplendor, Minas Gerais, bibl. Brazil. In the same state are very high quality rose The author comprehensively researched the che quartz crystals at the Pitora Mine near Galilea and mical properties of emeralds from different locali fine colour zoned elbaite crystals from Barra de ties world-wide. This first part deals with Brazilian Salinas. Fine quality zoned elbaite is also reported emeralds. About 200 samples were examined by J. Gemm., 1991,22,6 377

microprobe. The amount of variation and mean and schists from the Kokchetav massif, northern concentration of the elements chromium, iron, Kazakhstan, USSR. Kyanite, mica, rutile, sphene, magnesium and sodium are tabulated. The results clinopyroxene and zircon occur as inclusions in are also correlated in graph form. E. S. garnet; the inclusions are often intergrown with diamond. It is thought that the material of the host SCHWARZ, D., 1990. Turmalin als Einschluss in protected the diamonds from retrogressive trans Beryll. (Tourmaline as an inclusion in beryl.) formation to graphite. M. O'D. Zeitschrift der Deutschen Gemmologischen Gesell- schaft, 39,4,191-2,1 fig. in colour (on front cover SOLANS, J., DOMENECH, M.V., 1990. Estructura of issue). cristalina, composition quimica y propriedades The author describes the crystals of brown fisicas de las gemas II. La dureza. (Crystal tourmaline found as inclusions in a colourless beryl structure, chemical composition and physical from the Governador Valadares district, Minas properties of gemstones. II. Hardness.) Gemolo- Gerais, in Brazil. Tourmaline is a common inclusion gia, 32, 85/86. 13-20,1 fig. material in beryl from many localities (Zambia, The use of hardness in gem testing is discussed. Urals, Habachtal, Madagascar, Socoto and Car- M.O'D. naiba). Beryl as an inclusion in tourmaline is rare. The author explains this be a definite crystallization SOSSO, F., SOI, V., PlLATI, T., DlELLA, V., LoBOR- sequence, the boron-rich phase coming before the io, G., GRAMACCIOLI, CM., 1989. Alessandrite beryllium enrichment. E. S. sintetica: nuovi dati cristallografici ed analitici. (Synthetic alexandrite: new crystallographic and SCOVILL, J.A., WAGNER, L., 1991. The Fat Jack analytical data.) La Gemmologia, 14, 3/4, 7-21, 9 mine, Yavapai County, Arizona. Mineralogical figs (5 in colour). Record, 22,1, 21-8,19 figs (9 in colour). Synthetic alexandrite from the USSR is ex Fine crystals of amethyst and smoky quartz are amined and found to be Cr-rich and Fe-poor. found at the Fat Jack mine, Yavapai County, Negative crystals in parallel arrangement and with Arizona. The mine is located in a large schist crystalline phases within are characteristic of the inclusion in the Crazy Basin quartz monzonite. product. M.O'D. Some of the quartz takes the sceptre form. M.O'D. SOUZA, R.A., WILSON, W.E., GANGEWERE, R.J., SENA SOBRINHO, M. DE, 1985. Notas sobre aluvioes WHITE, J.S., KING, J.E., 1990. The Hillman Hall diamantiferas do Estado de Minas Gerais, Brazil. of Minerals and Gems, the Carnegie Museum of (Notes on diamond-bearing placers in the state of Natural History, Pittsburgh. Mineralogical Re Minas Gerais, Brazil.) Iheringia. Serie Geologia, cord, 21, 5, 32pp [outwith the main pagination of 10,3-18,14 figs. the issue], 54 figs in colour. A study of the diamond-bearing placers of the Fine crystals of peridot, grossular garnet, topaz, main producing areas of Minas Gerais, Brazil, tourmaline and quartz, are among the exhibits showed that at least three geological ages for alluvial featured in the recently re-opened display. M.O'D. fertile deposits have been defined. M.O'D. WADE, K., FUJINUKI, T., 1988. (Factors controll SOBCZAK, T., SOBCZAK, N., 1990. Die klassischen ing amounts of minor elements in pearls.) Journal polnischen Chrysopras-Vorkommen von Szklary of the Gemmological Society of Japan, 13, 1/4, in Niederschlesien. (The classic Polish chrysop- 3-12, 5 figs. (In Japanese.) rase location of Szklary in Lower Silesia.) Lapis, A chemical analysis compared the amounts of 15,10, 29-31, 3 figs (2 in colour). minor elements in pearls with those in molluscan The Polish chrysoprase deposit at Szklary in shells. In general seawater pearls have larger Lower Silesia is described. The chemical and amounts of alkaline earth elements, alkali metal physical details of chrysoprase are given. M.O'D. elements and anion elements, while freshwater pearls are rich in manganese. M. O'D. SOBOLEV, N.V., SHATSKY, V.S., 1990. Diamond inclusions in garnets from metamorphic rocks: a WEERTH, A., 1991. Neue Mineralfunde aus den new environment for diamond formation. Na beriihmten pakistanischen Edelsteinpegmatiten. ture, 343, 742-6,2 figs. (New mineral discoveries from the famous Pakis Cubo-octahedral diamonds averaging 12 /xm in tan gem pegmatites.) Lapis, 16, 1, 36-7, 3 figs in size are found in zircon and garnet from high- colour. pressure metamorphic garnet-pyroxene and Tabular crystals of a pinkish apatite, prismatic pyroxene-carbonate-garnet rocks, biotite gneisses morganite and schorl crystals with colourless topaz 378 J. Gemm., 1991, 22, 6 on albite are reported from the gem pegmatites of 1990. Fluorit. (Fluorite.) [Single topic issue of] Stak-Nala, Shigar-Dassu and Shingus respectively. Emser Hefte, 11, 3, illus. in black-and-white and All these locations are in the northern areas of in colour. Pakistan. M.O'D. World fluorite occurrences are described, the main emphasis being placed on German-speaking WIGHT, W., 1988. Kamieni szlachetne i ozdobne countries. Extensive lists of references are provided. Kanady. (Gems and ornamental stones of Cana M.O'D. da.) Mineralogia Polonica, 19, 1,119-29,1 fig. Translation of a paper first appearing in Journal of Gemmologie Aktuell, 2/90. [No individual authors.] the Gemmological Society of Japan, 8, 27-39, 1983, The issue includes descriptions of: violet scapo- and the Journal ofGemmology, 18,6,544-62,1983. lite from Afghanistan; tourmaline and kunzite M.O'D. cat's-eyes from Brazil and a zoned tourmaline coloured purple and rose-colour from Paraiba, WILKE, H.-J., 1990. Die mineralogische Sammlung Brazil; colourless, light yellow and light green des Natural History Museum in London. (The montebrasite from Brazil; alexandrite from Orissa, mineral collection of the Natural History India, and an Indian ruby cat's-eye; yellow, yellow Museum in London.) Lapis, 15,10,13-24,16 figs ish-brown and brown parisite from Colombia; (12 in colour). adularescent orthoclase from Austria; star chry- The history and present arrangement of the soberyl from Sri Lanka; rose-coloured spinel from mineral collections of the Natural History Museum the USSR and ruby from the Pamirs where the in London are described. Some outstanding miner USSR borders China; facetable hodgkinsonite from al specimens are illustrated. M. OT). Franklin, NJ, USA; ruby and sapphire from North Vietnam. A synthetic ruby made from polycrystal- WILSON, W.E., 1991. What's new in minerals? line material is also reported. M. O'D. Mineralogical Record, 22,1, 53-5, 8 figs in colour. Fine crystals of red beryl from the Violet claims in the Wah Wah mountains of Utah feature in this 1991. FM-IGMS-MSA symposium on azurite and short article together with stalactitic groups of other copper carbonates. Mineralogical Record, rhodochrosite from the La Capillita mine, Catamar- 22,1,64-9, 9 figs (8 in colour). ca, Argentina, and beryl from Dusso, Pakistan. The papers abstracted are: Ribbe and Eriksson M.O'D. on azurite and malachite, chemically and structural ly related minerals: North on azurite and malachite WOLLAERT, E., VOCHTEN, R., VAN LANDUYT, J., from the Morenci and Metcalf mines, Greenlee 1990. Characterisation of gem opal and inferior County, Arizona: Wenrich on azurite and other opal qualities by means of electronmicroscopy. copper carbonates in northern Arizona solution- Zeitschrift der Deutschen Gemmologischen Gesell- collapse breccia pipes. M.O'D. schaft, 39, 4, 211-23,, 11 figs, 1 graph, bibl. The structural differences between gem opal and 1990. Guinean diamond production: a model to be potch are investigated by means of the electron emulated? Mazal U'Bracha, 34, 43-50, 10 figs( 8 microscope. Potch does not show any play of colour in colour). because it lacks the necessary complete uniformity The article describes the progress made recently of a perfect stacking of perfect spheres of identical in exploiting the diamond mines of Guinea. M.O'D. size and absence of void filling with silica. In gem opal the colour grains of the surface are the result of 1985. 'Khotan' jade, past and present. Bulletin of the different orientation of the microscopic planes that Friends of Jade, 4,40-50, 1 fig. constitute the surface. E. S. Some accounts of Khotan and its jade deposits are extracted from the literature. M.O'D. ZHILIANG, N., 1983. Preface to collected illustrated works on ancient jade. Bulletin of the Friends of Jade, 3, 58-62. Seventeen Chinese language books on jade are briefly summarized with brief notes on bibliogra phy and text. M.O'D. J. Gemm., 1991,22,6 379

Book reviews

ANNELS, A.E., BURNHAM, B.C. (EDS), 1986. The terns, polymorphism and series are also given: Dolaucothi gold mines. 2nd edition. Division of major locations are given in all cases though of Mining and Minerals Engineering, School of necessity these have to be selective. Engineering, University of Wales College of The book is very well produced and when we Cardiff, Cardiff, pp.62. Illus. in black-and-white. realize that there were over 3,000 distinct species Price on application. known at the time of writing we can see that the Gold has been mined in this area of South Wales book is long overdue. M.O'D. at least as far back as Roman times and this study outlines the work done on reconstructing the BEVINS, R.E., SHARPE, T., 1982. Welsh minerals. mining history of the area. Mineralogy and geology National Museum of Wales, Geological Series no. are discussed and the archaeology of the site is 4, Cardiff, pp.9 [19]. Illus. in colour. £1.80. related to other sites in the vicinity. It is hoped that This small book in landscape format illustrates some of the mine may be established as a working thirty Welsh minerals, some with possible mine museum. M. O'D. ornamental application. Part of the economic and informative publishing programme of the NMW, ANTHONY, J.W., BIDEAUX, R.A., BLADH, K.W., this is a well-produced book, giving chemical NICHOLS, M.C., 1990. Handbook of mineralogy, composition, mode of occurrence, hardness, speci Vol. 1. Mineral Data Publishing, Tucson, USA. fic gravity, size of speciment depicted and location pp. vii, 588. US$82.50 plus $5.00 shipping. for the thirty selected minerals. M.O'D. It is now 40 years since the last volume of Dana's system of mineralogy was published and, apart from CRAM, L., 1988. Journey with colour. Lightning Michael Fleischer's Glossary of mineral species there Ridge, NSW Reproduced from typewriting. Un has been no up-to-date monographic treatment of paged. minerals since then. The present book devotes one This unusual production consists of typewritten page to all the known and accredited elements, sheets containing papers, or the whole text, from sulphides and sulphosalts up to 1988 in most cases. the Lightning Ridge Flash newspaper of the famous Further volumes will follow in due course; the Australian opal field. A great deal of interesting second will cover silica and the silicates, the third information is included. M.O'D. halides, hydroxides and oxides, the fourth arsen ates, phosphates, uranates and vanadates and the DABDOUB, T., 1985. Opal report from Honduras 'The fifth borates, carbonates and sulphates. Smaller fire still burns9. Tropical Gem Explorations, groupings will accompany larger related ones in the Metairie, LA. pp. iii, 61. Illus. in black-and-white appropriate volume and organics will be covered by and in colour. Price on application. volume 5. A useful guide to the opal fields and mining Each entry gives crystal data, physical pro industry of Honduras. At Erandique, the chief opal perties, optical properties, cell data, chemistry, locality, the stones are found in seams or veins occurrence, association, name, location of type penetrating basalt/trachyte rock. Various back material, where known and the best references. grounds are found with play of colour and stones Where known and appropriate X-ray powder pat from this area are not subject to crazing. Other 380 J. Gemm., 1991, 22, 6

mining areas are also described and the author structure. The remainder of the main text, over 200 includes some entertaining and informative anec pages, is devoted to the general and detailed dotes. M.O'D. description of the mineral deposits which are divided into the nine areas of the Escarpment, DIETRICH, R.V., SKINNER, B.J., 1990. Gems, gra Alston Moor, West Allendale, East Allendale, Wear- nites and gravels: knowing and using rocks and dale, Teesdale, Haydon Bridge and the Durham minerals. Cambridge University Press, Cam Coalfield. The book is well printed and the mass of bridge, pp. viii, 173. Illus. in black-and-white and detail is easy to work through; maps are clearly in colour. £15.00. lettered. M.O'D. The book attempts to answer the question 'Why study minerals?' and concentrates upon explana GILLARD, G., 1983. Gemfields. Boolarong Publica tions of the nature and use of mineralogy, petrology tions, Ascot, Queensland, pp. 60. Illus. in black- and soil science. The book begins with an overview and-white. Price on application. of the mineral world and then describes the crystal This attractive book contains sketches of mining line state and mineral chemistry. Later chapters life at the gem centres of Anakie, Rubyvale, Sap cover rocks, soils, dusts and muds, ores and ore phire and other centres in central Queensland. minerals, building materials and concludes with a M.O'D. discussion of rocks and minerals in diverse environ ments. Three appendices give a description of GRICE, J.D., 1989. Famous mineral localities of chemical symbols and the periodic table, identifica Canada. National Museum of Natural Sciences, tion of the common-rock forming minerals and the Ottawa, pp. 190. Illus. in colour. £16.95. identification of rocks. Coloured pictures of good The author presents some of Canada's most quality form a centre section. The book is presum interesting mineral localities chosen because he ably aimed at a wide readership and is a good particularly likes them. This idiosyncratic approach attempt to bring a complicated science to the makes for a readable book with quite good coloured attention of those who may one day take it up. pictures (though not quite up to the best standards M.O'D. of today). Among the localities producing minerals of ornamental interest are the Jeffrey mine, Asbes DUNHAM, K.C., 1990. Geology of the northern tos, Quebec, celebrated for grossular garnet; Thun Pennine orefield. Vol. 1. Tyne to Stainmore. 2nd der Bay, Ontario, an amethyst location; Nain, edition. HMSO, London, pp. x, 299. Illus. in Labrador (labradorite); Baffin Island (lapis-lazuli); black-and-white and in colour. £32.00. the Cassiar Mountains, British Columbia The northern Pennine orefield is one of the (nephrite). Other sections describe the naming of world's major producers of fluorite in both commer minerals, mineral identification and mineral forma cial and specimen qualities. This new edition tion, but this varied information is made part of the general treatment of particular localities. There are replaces one which had become a quarry for useful lists of minerals by locality (those described collectors and covers that part of the orefield which in the text) and a good bibliography. This is a good contains the most productive fluorite deposits. All book to give to someone beginning to study miner mines, both working and abandoned, are described als, whether they plan to visit Canada or not. The in considerable detail with plans of the most style is personal and friendly and the price gives important veins. Each chapter has its own list of very good value for today. M. O'D. references and a final chapter comments on future prospects for the area. Baryte and witherite, both long sought by collectors, are also prominent in this HAILL, R.G., 1982. Opals of the Never Never. Castle area. The books forms an economic memoir cover Books, Cammeray. pp. viii, 152. Illus. in black- ing the areas of 1:50,000 and one inch geological and-white and in colour. Price on application. sheets 19 and 25, with parts of sheets 13, 24, 26, 31 Paperback reissue of the book first published in and 32 (England and Wales). Having spent many 1981*. M.O'D. hours at many of the working and abandoned sites above and below ground, I can strongly recommend HAMMOND, C, 1990. Introduction to crystallography. this book which I saw in proof some years ago and Oxford University Press and the Royal Microsco greatly welcome now. pical Society, Oxford, pp. viii, 101. Illus. in The book begins with a history of mining in the black-and-white. £19.95. area followed by a survey of the country rock of the This short book forms Vol. 19 of the Royal Lower Paleozoic foundation and sedimentary stra Microscopical Society's Microscopy Handbooks and tigraphy. Next comes a survey of the igneous provides a question-and-answer format with useful intrusions followed by an overview of the general *Reviewed Journal of Gemmology, XVIII, 5, 444. - Ed. J. Gemm., 1991,22,6 381

notes on computer programs to assist learning what use of enamel. One or two pages from the catalogues is described as a very simple subject. Black-and- of designers are reproduced and it is plain that white photographs illustrate various types of pack earrings were now intended to be used by a much ing but as always the paucity of well-formed natural wider social group. crystals prevents photographic illustration in depth By the present century experiment with earrings (cost may also play some part in this). A useful could be seen in many countries and above all this appendix gives biographical details of celebrated has been the century in which earrings gave desig crystallographers and the names and addresses of ners the opportunity to display their products. crystal-making kits are given. Otherwise the treat Many designers have been one-person workshops ment of the subject follows established lines. and innumerable attractive pieces are seen in daily M.O'D. use. This chapter outlines developments before the First World War and then decade by decade. HOLBECHE, S., 1989. The power of gems and crystals: With the close of the historical survey the book how they can transform your life. Piatkus, London. goes on to give biographical notes on the major (Reprinted 1990.) pp. 185. Illus. in black-and- designers and a glossary and index. There is a short white and in colour. Price on application. but useful bibliography; here space prevents cita Whatever your opinion on the power of inanimate tion of periodical articles. This is a most enjoyable objects to alter human health and behaviour, this is book and successfully bridges the sometimes im- an attractively produced book whose contents will aginery gap between a work relying only on its help many to get through life if no other source of illustrations and a purely scholarly undertaking. inspiration or comfort is available. Some at least of M.O'D. the gemmological material is accurate, but this is not the first purpose of the book. M.O'D. MUMME, LA., 1988. The world of sapphires. MASCETTI, D., TRIOSSI, A., 1990. Earrings from Mumme Publications, Port Hacking, NSW, Au antiquity to the present. Thames and Hudson, stralia, pp. xvii, 189. Illus. in black-and-white London pp. 224. Illus. in black-and-white and in and in colour. Price on application. colour. £30.00. Early October 1990 was a time of corundum for this reviewer since both this book and the Richard Two members of the staff of Sotheby's have Hughes book, Corundum, arrived in the same week. collaborated in the production of a recognizable There is no need to compare the two - both are Thames & Hudson book; large, well printed and first-class, but the work under discussion deals only with carefully chosen illustrations of high standard with the various types of sapphire and omits ruby. of reproduction and captioning. By far the largest section is devoted to the sapphire Worn throughout recorded history by men and regions of the world though the book opens with a women, earrings are perhaps the most popular item discussion of the types of sapphire and ends with of jewellery and are found in all civilizations with the more usual details of properties and testing, access to any form of ornamental material. This synthetics and fashioning. The chapter on the world makes the field of study so wide that a single book deposits gives a particularly rich amount of detail on could not cover it adequately and for this reason Australian occurrences and this alone makes the male and ethnic earrings have been omitted. The book well worth buying. Many of the deposits are authors also make the point that at the time of depicted on maps and there are some, though not writing earrings have seen the greatest develop many, bibliographical references. ments in materials and design, especially in the past few years when the number of materials used has This is an attractive book, written in a style which never been greater. The book begins by surveying demands many very short paragraphs, and it is the historical background from antiquity to the clearly aimed at students. There are a number of seventeenth century. At the end of this period misprints which should have been caught but they earrings had become complicated and the eight in no way detract from the quality of the book. I eenth century saw a more subdued elegance with should have liked to see a much larger bibliography the use of the girandole consisting of a surmount and better quality colour pictures - some of those in with detachable drops, the style first coming into the book are amateurish and do not show the detail use in the middle of the preceding century. This of their subject. For several reasons the picture design followed changes in fashion and hair styles showing mounted sapphires would have been better and gave jewellery makers the chance to use a omitted. M.O'D. variety of stones in fairly large sizes. The nineteenth century saw a renewal of experiment, with compli NEWBURY, C, 1989. The diamond ring: business, cated designs, classical imitations and considerable politics and precious stones in South Africa. 382 J. Gemm., 1991, 22, 6

Clarendon Press, Oxford, pp. xvi, 431. Illus. in The area also produces gold and there are many black-and-white. £42.50. references to gold recovery as well as to that of The book studies the history and production of emerald. Useful details of the geology are given and diamonds with their marketing from the time of the there are text maps which help to place the area. Kimberley diamond rushes and the rise of De Beers Even more useful are the citations to newspaper to the formation of the Central Selling Organiza articles and to obscure journals which would other tion. In the preparation of the book many sources wise be impossible to trace. M. O'D. hitherto unpublished have been drawn upon; these include mining company archives as well as public ones. The sources, as well as a most useful bibliogra ROBERTSON, R.S., SCOTT, D.C., 1990. Geology of phy, can be found at the end of the book. A Coober Pedy precious stones field. Geological Sur considerable amount of labour history and of the vey of South Australia, Adelaide. (Geological effects of diamond sales on the overall economy of Survey of South Australia. Report of investiga South Africa forms the main theme which opens tions.) pp.55. Illus. in black-and-white and in with a study of ownership and governance, 1867- colour. Price on application. 1889. The development from loose miners' oligar The report summarizes work on the Coober Pedy chies led to company consolidation and thence from opal fields during 1981-1986 giving details of each monopoly to cartel over the years 1890-1919 with worked claim. Excellent colour photographs show the beginning of the De Beers operations. This the various kinds of rock in which opal has been second part of the book takes up the years to the end found to occur and there is a general summary of the of the First World War and the formation of area geology to open the book. A geological map of Consolidated Diamond Mines. The third and last the area comes in a pocket at the end of the report. part of the book deals with the cartel contracts, M.O'D. alluvial mining, the Diamond Corporation, cutting and industrial outlets and a survey of the strategy of diamond marketing and the formation and control SCHUBNEL, H.-J., 1990. Cristeaux precieux. (Pre of the diaxnond stockpile. This is a most interesting cious crystals.) Museum National d'Histoire survey of a complicated topic and should be Naturelle, Galerie de Mineralogie, Paris, pp. 40. required reading for anyone working on the politics Illus. in black-and-white and in colour. Price on and economics of mining; it also helps to straighten application. out some of the intricate details of the development This is a beautiful catalogue, with short accounts of the De Beers organization and of the near- of various aspects of the mineral collections of the monopoly that it holds. M.O'D. Natural History Museum in Paris. Among the gem quality specimens illustrated are Brazilian beryl O'DONOGHUE, M., 1990. Kvartz. (Quartz.) Mir, crystals and emerald crystals from Colombia. Moscow, pp. 135. Illus. in black-and-white and in M.O'D. colour. 85 kopecks. (In Russian.) Russian edition of the author's Quartz, first published in 1987. (Author's note) M.O'D. SCHUBNEL, H.-J., 1987. Larousse des mineraux. (Minerals of Larousse.) 2nd edition. Librairie PALMER, A., 1990. Poona WA and the seekers of its Larousse, Paris, pp. 365. Illus. in colour. Price on emeralds. Lap Industries, North Lake, WA. pp x, application. 97. Illus. in black-and-white. Price on applica This well-produced book describes a very large tion. number of minerals in alphabetical order. Each This is an excellent account of the finding and description includes chemical composition and exploitation of the emerald deposits in the Poona crystal system, note on nomenclature and the main area of Western Australia. The book begins with the constants. Very brief locality notes are given and mining and social history of the area and goes on to preliminary material covers the usual introduction describe the finding of emerald. The deposits began to chemistry, crystallography and the history of to be worked commercially in the 1920s but work mineralogy. The standard of illustrations is quite declined in the late 1930s, to be revived later. For high but does not reach present-day levels of some years exploitation and recovery appeared to achievement. The lack of a bibliography is a serious have failed to reach the levels expected but in the fault and the small print may make reading difficult 1970s a number of efforts to revive production were for some. Notes on French nomenclature variation made. At the time of writing a further period of provide a certain charm as does the use of rhom- inactivity seems to have succeeded one of small bohedral as a name for the trigonal crystal system. production. M.O'D. J. Gemm., 1991,22,6 383

SNOWMAN, A.K. (ED.), 1990. The master jewelers. by John Wiley in 1966 and was planned to form the Thames and Hudson, London, pp. 262. Illus. in first of a series covering all the European countries. colour. £28.00. Standards of production have improved since then Fifteen major jewellers of the period from 1850 to and the projected series never materialized but this the present are discussed with illustrations of some book is a pleasure to read and use, with high-quality of their finest pieces. The jewellers are Castellani illustrations, diagrams and maps. Some Swiss and Giuliano (taken as one), Fontenay, Hancock, minerals are gemmologically interesting if not signi Falize, Boucheron, Faberge, Tillander, Lalique, ficant and in any case greater awareness of Alpine- Vever, Fouquet, Tiffany, Cartier, Van Cleef and type mineral associations is always valuable. Among Arpels, Verdura and Bulgari. There is a section of minerals with ornamental or specimen importance useful notes and a bibliography at the end of the are fluorite, quartz and sphene. M.O'D. main text. The standard of colour reproduction is very high and the book provides an attractive WYKOFF, G.L., 1982. Beyond the glitter. Adamas introduction to the period for the jewellery histo Publishers, Washington DC. pp. iv, 206. Illus. in rian and student of the decorative arts. M.O'D. black-and-white. $17.95. The book attempts to give jewellers and their WEIBEL, M., GRAESER, S., OBERHOLZER, W.F., customers some idea of the principles behind STALDER, H.-A., GABRIEL, W., 1990. Die Min- gemstone and jewellery purchasing, valuation and eralien der Schweiz. Fiinfte Auflage. (Minerals of care. While very many small details are inaccurate Switzerland. Fifth edition.) Birkhauser Verlag, and much of the writing rather breathless, the book Basel, pp. 222. Illus. in black-and-white and in succeeds fairly well in its task and does include colour. DM48.00. much material which would be hard to find without The first edition, by Weibel alone, was published a good deal of searching. M. O'D. 384 J. Gemm., 1991, 22, 6

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

OBITUARIES MEETING OF THE COUNCIL OF Mr Edward H. Tindall, FGA (D. 1950), Poole in MANAGEMENT Wharfedale, died in January 1991. At a meeting of the Council of Management held on 13 March 1991 at 1 Burlington Gardens, London NEWS OF FELLOWS W1X 2HP, the business transacted included the Michael O'Donoghue gave lectures on gem- election to membership of the following: stones to Ightham Historical Society on 16 January 1991 and to the West Kent Radio Society on 18 Fellowship January 1991. Chen, Xiugin, Hubei Province, China. 1990 Cook, Peter B.,Bewdley. 1958 Alan Hodgkinson, Alan Jobbins and Kenneth Fu, Lintang, Hubei Province, China. 1990 Scarratt gave lectures at the Tucson (Arizona) Gem Li, Yali, Hubei Province, China. 1990 and Mineral Fair in February 1991. Their subjects Liao, Xiangjun, Hubei Province, China. 1990 were respectively 'A taste of Scottish gemmology', Nazareth, Christopher T, Bombay, India. 1990 The Cheapside Hoard' and The diamond connec Porebska-Brozyna, Dorota, E. Rutherford, NJ, tion'. USA. 1990 Puerto Albero, Magdalena, Baneres, Spain. 1990 MEMBERS' MEETINGS Qi, Lijian, Hubei Province, China. 1990 London Temelcoff, Catherine F, Toronto, Ont., Canada. On 26 March 1991 at the Flett Theatre, Geologic 1990 al Museum, Exhibition Road, London SW7, films Wang, Manjun, Hubei Province, China. 1990 were made available by De Beers, covering many Wezel, Annemarie, Den Haag, The Netherlands. aspects of the diamond industry. 1986 Wu, Haiou, Hubei Province, China. 1990 Midlands Branch Yan, Weixuan, Hubei Province, China. 1990 On 18 January 1991 at the Society of Friends, Dr Zeeman, Walentin, Bunnik, The Netherlands. 1990 Johnson House, Colmore Circus, Birmingham, Dr Zhang, Liangju, Hubei Province, China. 1990 J.C. Wright gave a talk entitled 'Macro to micro'. On 15 February 1991 at the Society of Friends, Ordinary Membership Mr Nick Sturman gave a talk entitled 'Pearls and Araki, Kazuo, Hyogo Pref, Japan. pearl identification'. Asano, Isamu, Osaka, Japan. On 15 March 1991 at the Society of Friends, Dr Banks, Mary, Exeter. Roger Harding spoke about the work of the Blackett, Barbara, Windsor. Geological Museum and also that of The Gemmolo Bowles, Michael, Pretoria, S. Africa. gical Association and Gem Testing Laboratory of Bradford, Christine L., Hassocks. Great Britain. Brooks, Anna T, Watford. Brown, Par vis S., London. North West Branch Callaghan, Stephen, Horsham. On 16 January 1991 at Church House, Hanover Carmona, Charles, Los Angeles, Calif., USA. Street, Liverpool 1, Mr Kenneth Snowman gave a Cassidy, Lucinda, Bristol. talk entitled 'Little boxes'. Chariot, Donald R., Ruislip. On 20 February 1991 at Church House, Mr John Day, Brynley J., Oldham. Pyke gave a talk entitled 'A gem collection'. De Kock, Jhr H.M., Gouda, The Netherlands. F.G.A. your key to the fascinating world of Gemmology

The Gemmological The Gemmological Association and Gem Association's course Testing Laboratory of has been specially Great Britain has been compiled into a series actively involved in of teaching modules the very beginning of that are both readable Gemmology as an and lavishly independent science. illustrated. Today, the Together they Association takes provide a pride in its | comprehensive step- international by-step guide to the reputation as a learned fascinating world of society dedicated to gemmology and an the promotion of opportunity to earn gemmological the coveted initials education and the FGA - Fellow of the spread of Gemmological gemmological Association. knowledge. To find out more The Association's Gemmological Association complete the coupon coveted Fellowship is below and we will a mark of excellence and Gem Testing Laboratory immediately forward only bestowed upon Of Great Britain the Association's individuals who 1991 prospectus successfully undertake the Association's giving full details of this unique course written and practical examinations covering all aspects of gemmology as a science. [flease complete and return to the Gemmological Association Training Scheme. I ' 27 Greville Street, London EC1N 8SU England Tel: (071) 404 3334. Fax (071) 404 8843 I

I Name _

Position _

| Company^

. Address _

Telephone _ Lr. rJ 386 J. Gemm.,1991,22,6

Dobashi, Yumiko, Osaka, Japan. Tsai, Yeou Y, Hsinchu, Taiwan, ROC. Downing, Lucy N., London. Tsurita, Kazuo, Osaka, Japan. Eckman, James, Boardman, Ohio, USA. Vaughan, Michael, Ellesmere Port Erker, Rianna S., Chicago, 111., USA. Wikstrom, Michael D., Iowa, USA. Fleitman, Beth, Milton, Mass., USA. Yamamoto, Atsuko, Hyogo Pref., Japan. Fruttauro, Patricia A., Kew. Yamamoto, Keiko, Shiga Pref., Japan. Fukushima, Hideaki, Tokyo, Japan. Yamamoto, Midori, Fukuoka-shi, Japan. Gofa, Sophia, Athens, Greece. Yamanaka, Kazuko, Osaka-fu, Japan. Hasegawa, Shoji, Saitama-ken, Japan. Yonehara, Machiko, Hyogo Pref., Japan. Hirakawa, Noritatsu, Osaka, Japan. Yoshikawa, Youichi, Hyogo Pref., Japan. Homer, Neil, Glasgow. Yumoto, Atuko, Osaka-fu, Japan. Hoso, Sadayuki, Osaka, Japan. Zhang, Youxu, Hubei Province, China. Imakubo, Kohei, Nara Pref., Japan. Ishida, Hiroyoshi, Osaka, Japan. CULTURED BLACK PEARL AUCTION Ishikawa, Noriko, Tokyo, Japan. The Cook Islands, a close neighbour of Tahiti and Ito, Yuko, Kanagawa-ken, Japan. one of the smallest island nations in the world, will Iwata, Takeshi, Hyogo-Pref., Japan. be holding its second Cultured Black Pearl Auction James, Robert C, St Maarten, Netherlands from 8 to 12 June 1991. Antilles. The Cook Islands have a large natural resource of Johns, Antony A., Freeport, Bahamas. Pinctada margaritifera from which the black pearl is Kadowaki, Kayoko, Osaka-fu, Japan. produced. The black pearl industry was introduced Kawabata, Toshikatsu, Saitama Pref., Japan. in 1986 by a Tahitian company and has expanded Kawabe, Makoto, Kyoto, Japan. rapidly. The pearls are grown in the atoll of Kawaguchi, Michie, Osaka, Japan. Manihiki, a small atoll with a population of 600 Kohara, Sanae, Osaka, Japan. people, located 400 miles away from its closest Kvasnik, Brian, Minnesota, USA. neighbour. Larkins, Barry, London. Approximately 30 farmers will be selling their Mansfield, Julia R., London. pearls with a minimum of 30,000 pearls being Maung, Thein L.O., Singapore. offered. The size range is expected to be mostly Minami, Kazumasa, Osaka, Japan. above 10mm, and of a high quality. The growth of Moon, You S., Osaka, Japan. each pearl takes, on average, a period of two years, Mori, Junko, Hyogo Pref., Japan. and requires individual attention by each farmer. Morikawa, Shuji, Osaka, Japan. Nishi, Tetsuomi, Hyogo Pref., Japan. For more information contact Cook Islands Pearl Oda, Hideki, Hyogo Pref., Japan. Farmers Association, PO Box 160, Rarotonga, Okamoto, Kyoko, Osaka, Japan. Cook Islands, South Pacific. Telephone: 682 21743, Oldfield, Gemma M., London. Fax 682 21543. Oyama, Keiko, Fukuoka-ken, Japan. Papi, Stefano, Rome, Italy. Verbal testing at Laboratory Preece, Susanne L., Trowbridge. Would Fellows and Associate Members please Rennes, Michael D., London. note that as from 1 April 1991 the charge for a verbal Romano, Rossella, Ilford. test on articles sent to the Laboratory by post will be Sandum, Mark A., Margate. £11.00 per stone (including VAT) plus £4.00 post Sato, Hiroshi, Tokyo, Japan. age and packing. The articles should be accompa Shibata, Kazue, Chiba-ken, Japan. nied by a cheque for the total amount made payable Shimada, Kiichiro, Saitama-ken, Japan. to the GA & GTL of GB. The goods will be returned Shin jo, Yasushi, Osaka, Japan. by Registered Post with a receipt for the amount Shirafuji, Hisaka, Osaka, Japan. paid. Smith, Julia, Sudbury. Sugihara, Hideko, Osaka, Japan. Takano, Hirofumi, Tokyo, Japan. Tanami, Kazuhiro, Kanagawa Pref., Japan. Tanigaki, Takako, Osaka-fu, Japan. Taniuchi, Toshiko, Osaka, Japan. Toft, Peter C., Copenhagen, Denmark. Trathen, John E., Stoney Creek, Ont., Canada. Tsai, Shwu-jen, Hsinchu, Taiwan, ROC. J.J. Gemm.,Gemm., 1991,22,61991, 22,6 387387

LetterLetter toto thethe EditoEditorr

From R. Keith Mitchell, FGAFGA H DearDear Sir,Sir, DI-IODOMETHANEDl-IODOMETHANE ANANDD ALLALL THATTHAT InIn mymy reviewreview ofof E.A.E.A. Jobbins'Jobbins' excellentlyexcellently revisedrevised H-C -H H_ C_H 10th10th editionedition ofof B. w:W Anderson'sAnderson's valuablevaluable texttext bookbook Gem Testing (The Journal of Gemmology, 22,22 , 4)4) I commentedcommented thathatt certaincertain namename changes,changes, particularlyparticularly thosethose ofof ourour oldold friendsfriends methylenemethylene iodideiodide anandd H mono-bromo-naphthalenemono-bromo-naphthalene 'might'might makmakee organicorganic chemistschemists happy,happy, butbut tendtend toto leaveleave establishedestablished MethaneMethane Di-iodomethaneDi-iodomethane gemmologistsgemmologists puzzled~puzzled', andand I wentwent onon toto wonderwonder whywhy thethe secondsecond ofof thesethese namesnames shouldshould exchangeexchange thethe Fig.!.Fig. 1. 'mono-''mono-' prefixprefix forfor thethe figurefigure 1,1, whilwhilee methylenemethylene SoSo 'di-''di-' inin di-iodomethanedi-iodomethane indicatesindicates thatthat therethere areare iodideiodide becomesbecomes di-iodomethanedi-iodomethane andand notnot 22-- twotwo atomsatoms ofof iodine,iodine, bubutt thethe 1 inin 11-- iodomethane.iodomethane. bromonaphthalenbromonaphthalenee indicatesindicates thatthat a brominebromine atomatom TheseThese commentscomments werewere mademade inin a somewhatsomewhat replacesreplaces a hydrogenhydrogen inin thethe twotwo linkedlinked six-sidedsix-sided 'tongue-in-cheek''tongue-in-cheek' frameframe ofof mindmind andand mightmight bbee ringringss thatthat comprisecomprise thethe naphthalenenaphthalene (CIOHg)(Ci0H8) molemole attributedattributed toto a dourdour outlookoutlook engenderedengendered byby a surfeitsurfeit culecule atat positionposition 1.1. TheThe hydrogenhydrogen positionpositionss araree ofof years.years. WeWe 'Golden'Golden Oldies'Oldies' tentendd toto dislikedislike changechange numberednumbered 1 toto 8 inin a clockwiseclockwise direction,direction, asas shownshown forfor thethe sakesake ofof change!change! inin FigureFigure 2.2. MrMr MorganMorgan mentionsmentions thatthat a compoundcompound However,However, I amam notnot anan organicorganic chemistchemist andand I diddid withwith twotwo brominebromine atomsatoms wouldwould havehave themthem aatt speakspeak outout ofof turnturn onon somethingsomething ofof whichwhich I knewknew positionspositions 1 andand 33 in in the the doubledouble ringring andand wouldwould bebe veryvery little,little, a factfact whichwhich mymy goodgood friendfriend anandd formerformer calledcalled 1-3-dibromonaphthalene.1-3-dibromonaphthalene. student,student, A.D.A.D. Morgan,Morgan, FIEF,FIBF, FGA,FGA, ofof Northfield,Northfield, Birmingham,Birmingham, whwhoo understandunderstandss thethe subjectsubject fafarr H H better,better, mademade plaiplainn inin a kindlykindly personalpersonal letterletter atat thethe endend ofof lastlast year.year. H H AnotherAnother letterletter onon thethe samesame lineslines waswas receivedreceived byby ourour EditorEditor inin February,February, fromfrom DrDr MartinMartin EF. Ansell,Ansell, ooff Blackheath,Blackheath, London.London. DougDoug MorganMorgan pointspoints outout thatthat thethe oldold namename 'methylene'methylene iodide'iodide' waswas a poopoorr oneone sincesince 'iodide''iodide' H H impliesimplies thatthat itit iiss a saltsalt ofof iodiciodic acid,acid, whichwhich itit isis not!not!

TheThe heavyheavy andand highlyhighly refractiverefractive liquidliquid (the(the heaviestheaviest H H knownknown atat normalnormal temperaturestemperatures apartapart fromfrom thethe metalmetal NaphthaleneNaphthalene (carbons(carbons omitted)omitted) mercury)mercury) isis basebasedd oonn methane,methane, CH4 (marsh(marsh gas!),gas!), inin whichwhich twotwo ofof thethe hydrogenhydrogen atomsatoms areare replacedreplaced byby H BBrr twotwo iodineiodine atomsatoms toto givegive CHzlzCH2I2 whichwhich isis nownow moremore logicallylogically andand correctlycorrectly namednamed di-iodomethane.di-iodomethane. TheThe H twotwo moleculesmolecules cancan bbee formulatedformulated diagramaticallydiagramatically asas inin FigurFiguree 11.. TheThe namename 1-bromonaphthalene1-bromonaphthalene isis againagain moremore accurateaccurate andand logicallogical thanthan monobromonaphthalene.monobromonaphthalene. H H I havehave alwaysalways thoughtthought thatthat thethe prefixprefix 'mono-''mono-' andand ththee figurefigure 1 werewere synonymous,synonymous, e.ge.g. . mono-rail,mono-rail, mono-syllable,mono-syllable, meaningmeaning oneone railrail oror oneone syllable.syllable. ButBut H H inin thethe farfar greatergreater complexitiescomplexities ofof organicorganic chemistrychemistry I-bromonaphthalene1 -bromonaphthalene theythey areare usedused toto conveyconvey differentdifferent meanings.meanings. Fig.Z.Fig. 2. 388 J. Gemm., 1991, 22, 6

Dr Ansell points out that my contention that the All this reflects the immense complexity of organic name could be written '2-iodomethane'is nonsense, chemistry in comparison with inorganic chemistry, since it implies the presence of two carbon atoms in which is largely our concern in gemmology. The the methane molecule when there is only one. The former is the chemistry not only of simple hydrocar di-iodomethane name makes clear that there are bons, but of life itself. While agreeing with Dr indeed two univalent iodine atoms which together Ansell that a knowledge of this greater science is with the two hydrogen atoms satisfy the tetrava- helpful, I thank Heaven that I am merely a Gemmo- lence of the one atom of carbon. logist, and perhaps too old to learn new tricks! I am indebted to both these gentlemen and I promise not to use 1-chrome when I mean Yours etc., monochrome. R. Keith Mitchell It will be noted that organic formulae need to be diagramatic in order to be explicit, and the actual 20 March 1991 naming describes the positions and the numbers of Orpington, Kent. replacing atoms, at least in the simpler compounds.

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9898 HattonHatton Garden,Garden, LondonLondon ECI N 8NX8NX R.M.WeareR.M.Weare & CompaCompannyy Limited.Limited. TelephoneTelephone 071-405071-405 0197152860197/5286 6767 TheThe MountMount York.York. England.England. Y02Y02 2AX.2AX. TelexTelex 2187921879 MinholtMinholt TelTelephonephone 0904-621984.0904-621984. Telex:Telex: 5769757697 YorvYorvex.ex.CC ~ IJ L9k '" GEMMOLOGICAL INSTRUMENTS LIMITED (a division of the Gemmological Association and Gem Testing Laboratory of Great Britain)

are now trading from:

1st Floor 27 Greville Street (entrance in Saffron Hill) London EC1N 8SU

Telephone: 071-404 3334 Fax:071-404 8843 Volume 22 No. 6. April 1991

ThcJournal of Gemmology

Contents

Sir Frank Claringbull 1911-1990 330

Pocahontas A.E.Farn 331

Gem thaumasite from the Black Rock Mine, South Africa U. Henn, M. Redmann and H. Bank 334 Gemmological teaching in Catalonia J.B.Nelson 337

The microscopic determination of structural properties for the characterization of optical uniaxial natural and synthetic gemstones Part 1 : General considerations and description of the methods L. Kiefert and K. Schmelzer 344

Emeralds from Colombia (Part 1) G. Bosshart 355

Sodium polytungstate as a gemmological tool W. W. Hanneman 364

Spessartine garnet in Brazilian topaz

J.I. Koivula, C. W. Fryer and R. C. Kammerling 366

Gemmological Abstracts 369

Book reviews 379 Proceedings of The Gemmological Association and Gem Testing Laboratory of Great Britain and Notices 384 Letter to the Editor 387

ISSN: 0022-1252

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