Volume 22 No. 8. October 1991 TheJournal 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 ijjr. G.F. Herbert Smith, CBE, MA, D.Sc. Sir Lawrence Bragg, CH, OBE, MC, B.Sc, FRS Sir Frank Claringbull, Ph.D., F.Inst.P., FGS Vice-President: R. K. Mitchell, FGA

Council of Management D.J. Callaghan, FGA N.W. Deeks, FGA N.B. Israel, FGA E.A. Jobbins, B.Sc, C.Eng., FIMM, FGA I. Thomson, FGA V.P. 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 P. 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., FGS, CH. Winter, FGA F. Inst. P., C.Phys., 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 G. H. Jones, B.Sc, Ph.D., FGA L. Bartlett, B.Sc, M.Phil., FGA D. G. Kent, FGA E. M. Bruton, FGA P. Sadler, B.Sc, FGS, FGA C. R. Cavey, FGA K. Scarratt, FGA A.T. Collins, B.Sc, Ph.D E. Stern, FGA A. E. Farn, FGA Prof. I.Sunagawa,D.Sc 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

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 EON 8SU Telephone: 071-404 3334 Fax: 071-404 8843 ^Journal of Gemmology

VOLUME 22

NUMBER EIGHT OCTOBER 1991

Cover Picture Cross section of ruby crystal with massive rutile inclusion. (Plate 5, 'The growth of rubies in south-east Kenya'by R.M. Key and J.O. Ochieng, p.484).

ISSN: 0022-1252 458 J. Gemm., 1991,22,8

THE GEM DIAMOND DIPLOMA

GAGTL have brought together the finest minds in the world of diamonds to produce the most comprehensive Gem Diamond home study course available. The course acknowledges the professionalism of the international diamond market and includes every aspect of gem diamond you will ever need to know.

Following an examination in theoretical knowledge and practical application - including grading of polished and rough, you may gain the Gem Diamond Diploma and be entitled to the special Diamond Membership of GAGTL With DGA after your name your professionalism will be obvious for all to see

For further information please contact Louise Macdougall on 071-404 3334, or complete the reply form below.

Please complete and return to GAGTL Education Department, 27 Greville Street, London EC1N 8SU

Name:

Address:

Telephone: JG 10/91 J.J. Gemm.,Gemm., 1991,22,81991, 22, 8 459459

AnAn unusualunusual assembledassembled inclusioninclusion specimenspecimen Robert C. Kammerling and John I. KoivulaKoivula

GemologicalGemological InstituteInstitute ofof America,America, SantaSanta Monica,Monica, CaliforniaCalifornia 90404,90404, USAUSA

Fig.Fig. I.1. ThisThis assembledassembled agateagate specimenspecimen weighsweighs 61.3961.39 caratscarats andand measuresmeasures 39.0039.00 x 30.4530.45 x 6.42mm.6.42mm. PhotograpPhotographh byby RobertRobert Weldon,Weldon, GemologicalGemological InstituteInstitute ofof America.America.

AbstractAbstract Additionally,Additionally, featuresfeatures detecteddetected underunder magnifica­magnifica­ ThisThis articlearticle reportsreports onon anan assembledassembled stonestone consistingconsisting tiontion areare ofof concernconcern inin gemgem identification.identification. WithWith thethe ofof glassglass andand dendriticdendritic agateagate components.components. proliferatioproliferationn ofof newnew syntheticssynthetics andand thethe growinggrowing IntroductionIntroduction availabilityavailability ofof so-calledso-called 'sophisticated''sophisticated' man-mademan-made InclusionsInclusions areare anan importantimportant featurefeature inin gemstonesgemstones gems,gems, inclusioninclusionss areare usuallusuallyy thethe mosmostt reliablereliable -- forfor a numbernumber ofof reasonsreasons.. ForFor thethe diamonddiamond grader,grader, sometimessometimes thethe onlyonly - meansmeans ofof determiningdetermining thethe thethe presencepresence ofof a minuteminute inclusion,inclusion, jusjustt visiblevisible withwith naturenature ofof a gem.gem. NoNo longerlonger isis itit jusjustt a questionquestion ofof lOxlOx magnification,magnification, cancan setset thethe clarityclarity gradegrade andand naturalnatural vs.vs. VerneuilVerneuil syntheticsynthetic rubyruby.. TodayToday wewe faceface greatlygreatly affectaffect ththee stone'sstone's value.value. AlthoughAlthough oftenoften lessless thethe possibilitpossibilityy ofof havinghaving toto identifidentifyy fluxflux syntheticsynthetic closelyclosely scrutinizedscrutinized fromfrom anan evaluationevaluation standpoint,standpoint, rubies;rubies; fluxflux blueblue,, pinkpink andand orangeorange sapphires;sapphires; 'eye-visible''eye-visible' inclusioninclusionss cancan alsoalso havehave a significantsignificant syntheticsynthetic opalopal inin a varietyvariety ofof bodbodyy colourscolours andand effecteffect on·on thethe valuvaluee ofof a colouredcoloured stonestone (in(in thisthis patternspatterns ttoo theitheirr play-of-colour;play-of-colour; syntheticsynthetic alexan­alexan­ regard,regard, 'blemishes''blemishes' onon pearlspearls areare alsoalso anan importantimportant dritedrite andand eveneven cat's-eyecat's-eye alexandrite;alexandrite; andand thethe listlist goesgoes consideration).consideration). on.on. Furthermore,Furthermore, eveneven whenwhen wwee dodo determine,determine, forfor

© CopyrightCopyright thethe GemmologicalGemmological AssociationAssociation ISSN:ISSN: 0022-12520022-1252 460 J. Gemm., 1991,22,8

example, that a ruby is natural, we may then have to substance (Nassau, 1983). Equally germane to this determine whether or not it has been heat-treated to discussion are 'most agate doublets'. These are modify colour and/or clarity, or had surface cavities produced by precipitating out manganese oxide filled with a glass to improve appearance and add dendrites within gelatine on a glass plate and then weight. gently heating to remove excess water; another glass Inclusions (and related structural features) are plate is then cemented on top and assembled stones also important in that they are responsible for some fashioned from the composite piece (Webster, of the most intriguing gems, those which display 1983). optical phenomena. Were it not for fine, parallel acicular crystal inclusions in chrysoberyl, there Description of specimen under investigation would be no cat's-eye stones; but for intersecting, In the spring of 1990, a resident gemmology oriented rutile 'needles' there would be no star student at the Gemological Institute of America in rubies and star sapphires. There would be no Santa Monica donated a most interesting assembled sunstone or aventurine feldspars had not minute stone for examination. The specimen, a very shal­ hematite or copper crystals precipitated out in these low-domed oval single cabochon (Figure 1), had gem materials. been purchased at the Tucson Gem and Mineral Show in February, where it was represented as a Altered inclusion specimens dendritic agate; there was no indication from the Occasionally we also come across gem materials vendor that the piece was assembled or in any other that have been treated with the apparent purpose of way altered. The stone, which weighs 61.39 carats fabricating or altering inclusions. Two such fabri­ and measures 39.00 x 30.45 x 6.42mm, is essential­ cated specimens the authors have examined were ly colourless and almost transparent where inclu­ colourless quartz crystals with man-made 'three- sions are not present. It exhibits an attractive phase' inclusions. Thin, tubular columns had been pattern of dark reddish to greenish brown dendrites drilled in from their bases and had been partially in the type of general pattern which in the US trade filled with a liquid. The final touch - 'phase three'- is referred to as 'plume' structure (Figure 2). One was a minute faceted gem; in one specimen this small, irregular area has a dark yellowish brown 'solid phase' was a blue gem, in the other, a bright colour with wavy, agate-like banding. red stone. Each stone had its base sealed with what When examined from the side, the assembled appeared to be a mixture of epoxy resin and quartz nature of the piece becomes obvious (Figure 3). The fragments (Koivula and Kammerling, 1989). top consists of a very transparent, colourless convex In 1986 the authors first saw faceted colourless as cap joined to a flat, light grey, semi-transparent to well as blue topaz containing brownish yellow translucent base. acicular inclusions. First described as 'rutilated' topaz, it was later shown that the inclusions were limonite-stained etched dislocation channels Magnification (Koivula, 1987). Late in 1988 one of the authors was When examined under magnification the cap shown similar material in which the inclusions were appears virtually inclusion-free. Between the cap a dark red-brown and which reportedly had been and base there is a fairly thick (approximately altered by heat treatment. Subsequent investigation 0.5mm) transparent, colourless layer containing showed that the heating had altered the limonite many minute, spherical gas bubbles (Figure 4). staining to hematite, changing the colour of the Using a straight metal pin and very little pressure it inclusions and making them more prominent was easy to both scratch and indent this layer, which (Kammerling and Koivula, 1989). we believe to consist of an epoxy or similar synthetic Also seen occasionally are translucent to semi- resin (or perhaps a 'gel-type' cement). Some of this translucent chalcedonies • containing large, epoxy-like material runs out over part of the cap and apparently artificially induced dendritic inclusions. some irregular drops of what appears to be this It is believed that the gems are first soaked in a material are found on the cap near the separation copper solution, after which an electric current is plane. The entire base of the stone is also coated applied in order to precipitate out a dendrite of with this material; several scratches (Figure 5) and elemental copper (Dunn et al, 1981; Koivula and other irregularities (Figure 6), some resembling Misiorowski, 1986; Koivula and Kammerling, human fingerprints, are noted on the coating. The 1989). The copper solution is also probably re­ base section, which is approximately 1.2mm thick, sponsible for the blue-green body colour of such contains (in addition to the dendritic inclusions treated gems. There is also a brief mention in the already described) some irregular, wispy, milky- literature of an agate cabochon on the back of which white areas, some of which show typical 'botryoidaP dendrites were engraved and then filled with a black or 'fortification agate' structure (Figure 7). J.Gemm., 1991,22,8 461

Fig. 2. The dendrites in the assembled stone exhibit an Fig. 3. When examined from the side, the assembled nature of attractive 'plume' structure. Photomicrograph by John the stone becomes obvious. Photomicrograph by John I. Koivula. Magnified 3x. I. Koivula.

Fig. 4. Numerous minute, spherical gas bubbles can be seen Fig. 5. A scratch can be seen in the colourless coating on the in the colourless cement layer between the cap and the base of the assembled agate. Photomicrograph by John base. Photomicrograph by John I. Koivula. Magnified I. Koivula. Magnified lOx. 40x.

Fig. 6. Irregular surface features, probably human finger­ Fig. 7. The typical agate structure was detected in some areas prints, were also noted on the coated base. Photomicro­ of the agate base. Photomicrograph by John I. Koivula. graph by John I. Koivula. Magnified 5x. Magnified 30x. 462462 J.J. Gemm.,Gemm., 1991,22,81991, 22, 8

GemmologicalGemmological propertiesproperties ththee epoxepoxyy anandd notnot ooff thethe underlyingunderlying chalcedony.chalcedony. InIn A spotspot refractivrefractivee indexindex readingreading taketakenn onon thethe apexapex thethe authorsauthors'' experienceexperience,, thisthis readingreading isis inin thethe rangerange ofof ththee capcap witwithh a DuplexDuplex IIII refractometerrefractometer revealedrevealed a ooff somesome syntheticsynthetic castingcasting resinsresins witwithh whicwhichh theythey valuevalue ofof 1.51,1.51, whilewhile a flat-facetflat-facet typtypee readingreading onon thethe havehave experimented.experimented. basbasee gavegave a valuvaluee ooff 1.56.1.56. NNoo birefringencebirefringence oror OnOnee mightmight asaskk whwhyy anyoneanyone wouldwould ggoo ttoo thethe pleochroismpleochroism wawass noted,noted, andand nono absorptioabsorptionn featuresfeatures bothebotherr ofof producingproducing suchsuch aann assembledassembled stone.stone. DrDr werewere detecteddetected usingusing a BecBeckk prisprismm spectroscopespectroscope EmmanuelEmmanuel FritscFritschh ooff ththee GIAGIA ResearcResearchh Depart­Depart­ mountemountedd onon a duaduall direct-transmission/fibre-opticdirect-transmission/fibre-optic mentment offeredoffered oneone possiblepossible explanationexplanation,, statingstating thatthat illuminatoilluminatorr basebase.. WheWhenn examineexaminedd face"upface-up inin thethe onlonlyy iinn a relativelyrelatively thithinn sectionsection mightmight thethe agateagate basebase polariscoppolariscopee betweebetweenn crossedcrossed polaroidpolaroidss ththee stonestone havhavee exhibiteexhibitedd ththee desiredesiredd 'plume''plume' effect;effect; thethe exhibitedexhibited anan aggregataggregatee reactionreaction;; whenwhen examinedexamined assemblagassemblagee alloweallowedd thisthis effeceffectt toto bbee seenseen inin a largerlarger througthroughh thethe side,side, paralleparallell toto ththee separationseparation plane,plane, (and(and perhapperhapss moremore durabledurable)) stone.stone. AnotheAnotherr possiblepossible thethe capcap gavgavee a singlysingly refractivrefractivee reactionreaction whilewhile thethe explanatioexplanationn iiss that,that, asas withwith somesome turquoiseturquoise anandd opal,opal, basbasee gavegave anan aggregateaggregate reactionreaction.. ThrougThroughh thethe thethe finishedfinished piecpiecee mamayy merelymerely havhavee beebeenn totooo thithinn toto carefucarefull ususee ooff hardneshardnesss pencilpencilss itit wawass determineddetermined havhavee offereofferedd adequateadequate durability,durability, henchencee thethe assemb­assemb­ thathatt ththee cacapp hahadd a MohMohss hardnesshardness ofof approximatelyapproximately lagelage.. 55Vz.1/2. ViewedViewed face-uface-upp underunder long-wavelong-wave ultravioletultraviolet AcknowledgemenAcknowledgementt radiationradiation,, nono fluorescencefluorescence was detecteddetected;; whenwhen ThThee authorsauthors wouldwould liklikee toto thanthankk MMrr PieterPieter examinedexamined paralleparallell ttoo ththee girdlegirdle planeplane,, however,however, thethe BennettBennett forfor bringingbringing ththee assembleassembledd 'plume''plume' agateagate epoxy-likeepoxy-like layelayerr waswas seenseen toto fluoresce a brightbright specimenspecimen totheitO'theirr attentioattentionn anandd forfor donatindonatingg iitt toto thethe bluisbluishh whitewhite.. ViewedViewed face-uface-upp undeunderr short-waveshort-wave GIAGIA PermanenPermanentt Collection.Collection. ultravioleultraviolett lightlight,, ththee stonestone fluorescedfluoresced a moderatemoderate chalkchalkyy yellow;yellow; examineexaminedd frofromm thethe side,side, however,however, itit References was seenseen thathatt ththee capcap was fluorescinfluorescingg a strongstrong References chalky yellow, the epoxy-like layer fluoresced a DunnDunn,, P.).,P.J., BentleyBentley,, R.E.R.E.,, Wilson,Wilson, W.E.W.E.,, 1981.1981. MineraMinerall Fakes.Fakes. chalky yellow, the epoxy-like layer fluoresced a Mineralogical Record, 12,4,12, 4, 197-219.197-219. moderatemoderate chalkchalkyy bluish-whitebluish-white andand ththee basbasee waswas KammerlingKammeriing,, R.C.R.C.,, Koivula,Koivula, J.I.).1.,, 1989.1989. ThermalThermal AlterationAlteration ooff inert.inert. InterestinglyInterestingly,, whewhenn viewedviewed throughthrough thethe basebase InclusionInclusionss inin 'Rutilated''Rutilated' Topaz.Topaz. Gems & Gemology, 25,25, 33,, ooff thethe cabochocabochonn ththee yelloyelloww fluorescencfluorescencee ooff ththee capcap 165-7.165-7. was masked. KoivulaKoivula,, J.I.).1.,, 1987.1987. TheThe RutilateRutilatedd TopazTopaz MisnomerMisnomer.. Gems && was masked. Gemology, 2323,, 2,2, 100-3.100-3. KoivulaKoivula,, J.I.).1.,, Kammeriing,Kammerling, R.C.,R.C., 1989.1989. GemGem NewsNews:: Man-madeMan-made ConclusioConclusionn andand discussiondiscussion 'Inclusion'Inclusion'' Specimens.Specimens. Gems&Gems & Gemology, 25,25, 1,45-6.1, 45-6. BaseBasedd onon ththee abovabovee testestt resultsresults,, iitt waswas determineddetermined Koivula,Koivula, J.I.).1.,, MisiorowskiMisiorowski,, E.E.,, 1986.1986. GemGem NewsNews:: ElectricallyElectrically TreateTreatedd ChalcedonyChalcedony.. GemsGems& & Gemology, 2222,, 44,, 246246.. thatthat ththee specimenspecimen waswas a glassglass andand dendriticdendritic NassauNassau,, K.,K., 1983.1983. Gemstone Enhancement. ButterworthButterworth & Co.Co. ('plume')('plume') agateagate doublet,doublet, ththee twotwo componentscomponents beingbeing (Publishers)(Publishers) Ltd.Ltd.,, London.London. joinejoinedd witwithh a colourlesscolourless cementcement layer.layer. AlthoughAlthough itit Webster, R.,R., 1983. 1983. Gems, Gems, Their Their Sources, Sources, Descriptions Descriptions and and Identification. Identi­ wouldwould appearappear inconsisteninconsistentt withwith ththee identificationidentification ooff 4th Editionfication. revised 4th Editionby B.W. Anderson,revised by Butterworth B. W. Anderson, Butter­ thethe basbasee section,section, thethe 1.561.56 RRII obtainedobtained forfor thisthis & Co.worth (Publishers) & Co. (Publishers) Ltd., London. Ltd., London. componentcomponent wawass probablyprobably duduee toto ththee thicknesthicknesss ooff thethe coatingcoating oonn thethe basebase,, thathatt isis,, ththee readingreading waswas thatthat ooff [[ManuscriptManuscript received 1818 April April 1990.J1990. ] J.J. Gemm.,Gemm., 1991,22,81991,22,8 463463

ContributionsContributions ttoo a historyhistory ofof gemmologygemmology CarlCarl PeterPeter ThunbergThunberg andand CeylonCeylon gemstonesgemstones John Sinkankas, Ph.D., GG, FMSAFMSA

SanSan Diego,Diego, CaliforniaCalifornia 9lO9,9109, USAUSA

TheThe literatureliterature ofof antiquityantiquity frequentlyfrequently mentionsmentions thethe especiallyespecially plantsplants thatthat werewere usedused forfor foodfood oror inin thethe gemgem richesriches ofof Ceylon,Ceylon, todaytoday knownknown asas SriSri Lanka,Lanka, nativenative economy,economy, whichwhich provedproved toto bebe thethe nexnextt largestlargest butbut onlyonly inin thethe 18th18th century,century, diddid a modern,modern, trainedtrained collectioncollection afterafter thatthat formedformed earlierearlier byby EngelbertEngelbert scientist,scientist, PeterPeter CarlCarl ThunbergThunberg (1743-1828),(1743-1828), Swed­Swed­ KaempferKaempfer (1651-1715)(1651-1715) alsoalso a visitorvisitor toto JapanJapan inin ishish medicalmedical doctordoctor andand naturalist,naturalist, systematicallysystematically 1690.1690. Thunberg'sThunberg's collectioncollection waswas dispatcheddispatched toto collectcollect andand describedescribe itsits gemstones.gemstones. TheThe accountaccount SwedenSweden andand formedformed thethe basisbasis forfor hishis monumentalmonumental first appeareappearedd inin a narrativenarrative ofof hishis voyagevoyage toto thethe FarFar Florajaponica,FloraJaponica, 1784,1784, inin whichwhich treatisetreatise hehe describeddescribed EastEast andand elsewhere,elsewhere, Resa uti Europa,Europa, Africa,Africa, Asia Asia ...... overover 300300 previouslypreviously unknownunknown plants.plants. HeHe leftleft JapanJapan 1770-1779, publishedpublished inin Uppsala,Uppsala, Sweden,Sweden, 17881788-- inin DecemberDecember 1776,1776, stoppingstopping duringduring hihiss voyagevoyage 93.93. HeHe brieflybriefly describesdescribes fourfour non-gemnon-gem mineralsminerals andand homehome inin Batavia,Batavia, Colombo,Colombo, CapeCape Colony,Colony, andand twentytwenty gemstonesgemstones whichwhich hereinherein areare affirmeaffIrmedd asas toto London,London, iinn thethe lastlast citycity makingmaking thethe acquaintanceacquaintance ooff identityidentity oorr suggestedsuggested aass beinbeingg differentdifferent fromfrom thethe a numbernumber ofof scientists,scientists, includingincluding SirSir JosephJoseph BanksBanks speciesspecies toto whichwhich assignedassigned byby Thunberg.Thunberg. (1743-1820).(1743-1820). HeHe arrivedarrived inin SwedenSweden inin 17791779 andand inin 17811781 was appointedappointed demonstratordemonstrator inin botanybotany atat BiographicalBiographical notenote Uppsala,Uppsala, andand thenthen succeededsucceeded hishis mentor,mentor, Linnaeus,Linnaeus, CarlCarl PeterPeter ThunbergThunberg was bornborn atat JonkopingJönköping onon asas ProfessorProfessor ofof BotanyBotany inin 1784.1784. ThunbergThunberg foundedfounded a 1111 NovembeNovemberr 17431743 wherewhere inin hishis youthyouth hehe attel).dedattended botanicalbotanical gardengarden atat UppsalUppsalaa andand gavegave toto hishis uni­uni­ locallocal schoolsschools thenthen enteredentered thethe UniversityUniversity atat UppsalaUppsala versityversity hishis largelarge collectioncollection ofof naturalnatural historyhistory objects.objects. forfor hishis higherhigher education.education. HereHere hehe obtainedobtained hishis InIn additionaddition toto thethe JapaneseJapanese botanybotany mentioned,mentioned, hehe doctoratedoctorate inin medicinemedicine inin 1770.1770. WhilWhilee atat UppsalaUppsala hehe alsoalso wrotewrote leonesIcônes plantarumJaponicum,plantarum Japonicum, 1794-1805, 1794-1805 , studiedstudied underunder thethe celebratedcelebrated naturalistnaturalist CarolusCarolus Prodromus plantarum, 1800,1800, andand Flora Capensis, LinnaeusLinnaeus (1707-1778)(1707-1778) whowho mademade himhim hishis protegeprotege 18071807-1812 -1812.. HeHe frrstfirst describeddescribed thethe remarkableremarkable SouthSouth andand declareddeclared himhim toto bebe hishis mostmost promisingpromising student.student. AfricanAfrican plantsplants knownknown asas thethe proteaproteass whilewhile thethe FroFromm thithiss mastermaster ofof naturalnatural historyhistory hehe receivedreceived thethe genus,genus, Thunbergia, containingcontaining 6565 speciesspecies andand muchmuch inspirationinspiration toto devotedevote almostalmost hishis entireentire lifelife toto studiesstudies cultivatedcultivated inin warmerwarmer climes,eûmes, was namednamed inin hishis inin thethe naturalnatural sciencessciences withwith greatestgreatest emphasisemphasis onon honour.honour. HisHis travelstravels provedproved popularpopular readingreading andand botanybotany.. However,However, immediatelyimmediately afterafter leavingleaving thethe werewere publishedpublished inin German,German, 1792-4,1792-4, inin English,English, universityuniversity hhee travelledtravelled toto ParisParis toto furtherfurther studystudy 1794-5,1794-5, andand inin French,French, 1794.1794. AfterAfter a usefuluseful andand medicinemedicine forfor oneone year.year. HereHere hehe receivedreceived anan invita­invita­ productivproductivee life,life, ThunbergThunberg dieddied atat Tunaberg,Tunaberg, nearnear tiontion fromfrom thethe DutchDutch EastEast IndiesIndies CompanyCompany toto actact asas Uppsala,Uppsala, onon 8 August,August, 18281828.. surgeonsurgeon andand naturalistnaturalist inin theirtheir colonycolony atat CapeCape Town,Town, SouthSouth Africa.Africa. SettingSetting sailsail fromfrom EuropeEurope hehe arrivedarrived atat HistoricalHistorical accountsaccounts ofof CeylonCeylon gemstonesgemstones thethe CapeCape inin AprilApril 1777,1777, andand forfor a perioperiodd ofof almostalmost ThisThis pleasant,pleasant, tropicaltropical island,island, lyinglying immediatelyimmediately threthreee yearsyears assiduouslyassiduously collectedcollected overover 3,0003,000 speciesspecies southsouth ofof thethe DeccanDeccan PeninsulaPeninsula ofof India,India, hashas beenbeen ooff plants,plants, ofof whichwhich overover 1,0001,000 werewere newnew toto science.science. identifiedidentified bbyy variousvarious namesnames asas Serendib,Serendib, Tapro­Tapro- AnAn opportunityopportunity nownow camecame hishis wawayy toto traveltravel bane,bane, anandd othersothers (Yule,(Yule, 1871;1871; GübelinGiibelin,, 1968;1968; CasCas­- fartherfarther toto Japan,Japan, againagain actingacting inin similarsimilar offIcialofficial son,son, 1989).1989). ItsIts gemgem treasuretreasuress werewere knownknown forfor somesome capacities.capacities. HeHe boardedboarded shipship inin 17751775 andand afterafter stopsstops centuriescenturies priorprior toto thethe ChristianChristian ereraa asas isis mademade clearclear inin thethe DutchDutch EastEast IndiesIndies eventuallyeventually arrivedarrived atat thethe inin thethe Periplus ofof thethe Red Red Sea,Sea, oror sea-trader's sea-trader's guideguide toto islandisland ofof DeshimaDeshima inin NagasakNagasakii HarbourHarbour toto whichwhich thethe RedRed SeaSea andand otherother NeaNearr EastEast waters,waters, a newnew placplacee thethe DutchDutch werewere confinedconfined byby orderorder ofof thethe translationtranslation ofof whichwhich hashas beenbeen mademade byby CassonCasson JapaneseJapanese government.government. DespiteDespite restrictionsrestrictions placedplaced (1989,(1989, esp.esp. pppp.. 230230 ft).ff). ByBy thethe beginninbeginningg ofof thethe firstfirst onon traveltravel andand socialsocial exchangesexchanges ThunbergThunberg managedmanaged centurycentury traderstraders knewknew ofof numerounumerouss animal,animal, veget­veget­ toto assembleassemble a largelarge collectioncollection ofof nativenative flora,flora, able,able, andand mineralmineral productsproducts ofof thethe region,region, allall ofof

© CopyrightCopyright thethe GemmologicalGemmological AssociationAssociation ISSN:ISSN: 0022-12520022-1252 464 J. Gemm., 1991,22,8

which were exchanged among Greek, Roman, information, and general accuracy. Its first edition, Egyptian, and Moslem merchants. Well into the Les six Voyages, etc., appeared in Paris in 1676. Christian era the fame of Ceylon's riches spread Tavernier visited Ceylon from May 12 to July 25, throughout the civilized world but the first reliable 1648, noting that "there are only two places in the eyewitness account appears to be that of Marco Polo East where coloured stones are obtained, namely in (1254-1324), famed Venetian adventurer, who vi­ the Kingdom of Pegu [Burma] and in the island of sited the island on his return trip from China Ceylon" (Tavernier, Ball-Crooke transi., 1925, 2, sometime between 1292, when he left China, and 77). Further, "the other place in the East whence 1295 when he arrived in Venice. rubies and other coloured stones are obtained is a Polo writes (Yule, 1871): "Now I will... tell you river in the island of Ceylon. It flows from high of the most precious article that exists in the world. mountains which are in the middle of the island, You must know that rubies are found in this Island and as the rains greatly increase its size - three or and in no other country in the world [sic] but this. four months after they have fallen, and when the They find there also sapphires and topazes and water is lowered, the poor people go to search the amethysts, and many other stones of price. And the sand, where they find rubies, sapphires, and King of this Island possesses a ruby which is the topazes. The stones from this river are generally finest and biggest in the world; I will tell you what it more beautiful and cleaner than those of Pegu" is like. It is about a palm in length, and as thick as a (ibid, p. 79). While Tavernier's first edition appeared man's arm; to look at, it is the most resplendent in 1676 the information on India's and Ceylon's object upon earth; it is quite free from flaw and red gemstones actually appeared beforehand in the as fire. Its value is so great that a price for it in 1665 edition of Chappuzeau's Histoire des Joy eaux, money could hardly be named at all. You must which, however, is said to be a pirating of informa­ know that the Great Khan [Kublai Khan, 1216- tion derived from Tavernier's 'original memoirs', 1294] sent an embassy and begged the King as a according to Valentine Ball (Tavernier, Ball-Crooke favour greatly desired by him to sell him this ruby, edit, 2,471-6). An English version of Chappuzeau is offering to give for it the ransom of the city, or in fact also known, published in 1671. Neither of the works what the King would. But the King replied that on contain any information which is not already in no account whatever would he sell it, for it had come Tavernier. to him from his ancestors". Yule (p. 256) 'comments on the story of this Thunberg's visit enormous 'ruby' as told by others who in the past Apparently Thunberg's knowledge of Ceylon's claimed to have some knowledge of it but offers gemstones was gained largely as a result of a several himself no explanation as to the stone's identity weeks stay at Matara, which gem district he visited even though it was probably obvious to Yule that it in response to an urgent request for his medical could not have been a true ruby. Alternatively, the attention to the wife of Count Rantzow, Dutch stone could have been a large tourmaline crystal, Comptroller of the 'factory' at Mature (as it was possibly red in colour and from Burma where in called). Thunberg states that "I daily made excur­ modern times at least, very large rubellite crystals sions in the vicinity of this place, and as the precious were found in the pegmatite mine at Sakangyi. stones of the island are found and dug up more Furthermore, Bauer (Spencer transi. 1904, p. 371) especially in these parts, I procured the proper notes that "two very fine specimens of crystallized intelligence, as well concerning the different kinds rubellite from Burma are exhibited in the Mineralo- of them, as the manner in which they are sought for gical Gallery of the British Museum, one of these, and made use of" (Engl, transi, p.215, ff.). He notes remarkable for its size and shape, being seven that the major part of gemstones are locally cut and inches high and six inches across, was given by the sold afterwards in India, it being the occupation of King of Ava to Colonel Symes when on an embassy the "poorer sorts of Moors to cut and polish them", to that country in 1795; the other, not so large, but referring here to the Moslems of Sri Lanka who of a fine deep colour, was presented to the Museum until recently monopolized the lapidary treatment in 1869 by Mr C.S.J.L. Guthrie". of native gemstones. Thunberg took care to buy After Marco Polo the next eyewitness from both rough and cut stones, the rough to be pre­ Europe appears to be Jean Baptiste Tavernier served with other 'fossils', i.e., mineral specimens, (1605-1689), the daring French traveller-gem mer­ which he collected during his travels. The non-gem chant, who made no less than six voyages to the species from Ceylon are few: an 'iron ore' found in Near East and into India, seeking and buying gems the earth and clay and suggesting limonitic or of great value for resale in Europe. His account goethitic concretions, mica in "large laminated makes fascinating reading and is still highly masses... the slivers of this are used for esteemed for its historical detail, gemmological ornamenting... umbrellas, made of large Talpat J. Gemm., 1991,22,8

IÜ^^^^^^^^Ä*»!

IM

^^^^SSffiS^ffiS^^

Fig. 1. Portrait (original in oils) of Carl Peter Thunberg by Per Krafft, The Younger, painted in 1808, now in the University of Uppsala, Sweden. Courtesy Dr. Kurt Boström. 466 J. Gemm., 1991,22,8

(Licuala) leaves", 'plumbago' or graphite, and especially from the Matara area, which have been 'stahlstein, or crystallized pyrites (or siderite), heat-treated to drive off colour. "used for making buttons of". White Tourmalin or Maturese Diamond: sudu ture­ The gemstones are as follows, with synonyms in mali (both Malab. & Singhal). "Topaz of pale English, Malabarese, Singhalese, and Swedish, the yellow colour", but Thunberg's Swedish gives it last added from Thunberg's article on same in the as 'gröngul', i.e., 'greenish-yellow'. transactions of the Swedish Academy of Sciences White Crystal: wille palingu, sudu palingu; hvit (Thunberg, 1784). The first name is from the crystall "Transparent and colourless mountain English translation (Thunberg, 1795). Crystal". Ruby: robyn, elinges chogeppu, lankaratte, rubin. WhiteSaphires or WaterSaphires: willie pad j an, sudu "Genuine ruby". padjan; hvit saphir or vatn-saphir. "Small frag­ Amethyst: scuandi (in Malabar. & Singhal.); Swed­ ments and slivers of the most transparent white ish like English. "Purple-coloured Mountain mountain Crystals". Crystal." Taripo: "a milk-coloured quartz". Robals: rauwa, rawa; granater. "Small transparent Yellow Crystal: man j el palingu, kaha palingu. "A Garnets of dark-red colour". lighter coloured smoky Topaz". Citrine. Hyacinths: No synonyms given; "made to pass for Brown Crystal: tillia palingu (both Malab. & Sing­ rubies". The name is classically assigned to red hal). "Smoky mountain Crystal, or a dark col­ zircon, which gemstone is abundant in Sri Lank­ oured smoky Topaz". Smoky quartz. an gravels in short prismatic tetragonal crystals Black Crystal: karte palingu, kallu palingu. "Partly and rounded pebbles. in Crystals, partly in fragments, is the Electrical Red Tourmaline: pania turemali, penni tourmalin; Tourmalin of Ceylon". Apparently referring here rod turmalin. "A quartz inclining to a red colour". to schorl. As with other colours of zircon, called indiscrimi­ Cafs Eye: wairodi (both Malabar. & Singhal); nately 'tourmaline', even today. kattöga. "Pseudo-Opal". Blue Saphire: nilem, nile; blâ saphir. "A genuine blueish coloured Saphire, frequently with blue Commentary spots", here probably referring to the many The meagre descriptions above are augmented sapphire crystals in Ceylon gravels that display for some stones in the text that follows the listing, pigmentation only in patches, zones, or thin skin giving colour qualities of ruby and amethyst, and areas. properties such as transparency and presence or Blue Tourmalin: nile turemali (both Malab. & absence of inclusions. Accurate identifications of Singhal.); blâ turmalin. "A Quartz, in colour gemstones, especially when in the form of rolled inclining a little to blue". pebbles and lacking morphological clues, were not Green Saphire: pat je padian (both Malab. & Sing­ easy in the last part of the 18th century, and even hal); grön saphir. "Genuine saphire". when Thunberg enlisted the aid of Torbern Berg­ Green Tourmalin: patje turemali (both Malab. & man it is obvious that mistakes still occurred. For Singhal), also called the "Maturese diamond", example, in Thunberg's discussion of ruby (p. 220), and noting that this name "is given to both he states that "most of them are round and flat, from Chrysolites with tetrahedral prisms, and even having been agitated and rolled about in the water", sometimes to the Chrysopras". In the Swedish which is actually more likely to be the case with version, Thunberg defines 'Grön Turmaline' as every other Sri Lankan alluvial gemstone than the occurring in 'fyrsidig prisma', again almost cer­ ruby or sapphire. The corundum crystals of these tainly describing tetragonal crystals of green gravels commonly display small to large remnants zircon. The 'chrysopras' used here is not further of crystal faces, and even when severely worn, they identified by Thunberg. present general shapes that are readily identified as Topaz: puresjeragen, purperagen, but the latter is belonging to crystals of this species. The confusion given in Thunberg's article as 'pusperagan'. in identity, or, rather, the application of the name "Genuine topaz". 'ruby' freely to any reddish stone, causing such Cinnamon-stone: komedegam (both Malab. & Sing­ confusion, is typified in Thunberg's following re­ hal); canelsten. "A fine flame-coloured or yellow­ mark in which he claims that "some [rubies] I have ish-brown garnet". Grossular. found crystallized with eight sides, of which four Yellow Tourmaline or Maturese Diamond: kaneke were broad, and four very small, and terminated by turemali (both Malab. & Singhal). "A Topez [sic] two points, consisting of four sides each", an of a greenish-yellow colour", but most likely excellent description of a typical doubly-terminated another colour phase of zircon; the second term zircon crystal displaying first and second order for many years has been applied to zircons, prisms and the bipyramid but not of a corundum JJ.. GemmGemm.,, 1991,22,81991,22,8 464677

crystalcrystal.. NexNextt hhee notesnotes thathatt "the"the MoorMoorss saysay thatthat analysis,analysis, essentiallessentiallyy allall aluminaluminaa andand onlonlyy a littllittlee ironiron thesthesee approacapproachh nearesnearestt toto ththee DiamonDiamondd iinn hardness,hardness, oxideoxide andand calciumcalcium oxideoxide,, whichwhich iiss nearlynearly identicalidentical toto anandd polispolishh themthem,, inin ordeorderr ttoo renderrender thethemm fifitt foforr currentlcurrentlyy accepteacceptedd analyseanalysess forfor corundumcorundum.. FromFrom beinbeingg setset inin rings'~rings", bubutt nownow itit seemsseems obviouobviouss thathatt thethe thithiss anandd otheotherr comparisoncomparisonss witwithh ththee analyseanalysess ooff MoorsMoors [Moslems][Moslems] areare speakingspeaking ofof truetrue corundumscorundums gemstongemstonee providedprovided earlierearlier bbyy BergmaBergmann iitt becomesbecomes andand notnot zirconszircons,, thethe differencedifference iinn hardneshardnesss betweenbetween cleaclearr whwhyy eveneven consultatioconsultationn withwith thithiss contemporarycontemporary ththee twotwo readilreadilyy apparentapparent toto anyonanyonee whwhoo hahass appliedapplied ooff ThunbergThunberg diddid nonott alwayalwayss resultresult inin accurateaccurate themthem toto ththee lapidary'slapidary's grindingrindingg wheel.wheel. identificationsidentifications ooff ththee gemstonegemstoness thathatt ThunbergThunberg TheThe difficultiedifficultiess iinn identificatioidentificationn thathatt besebesett Thun­Thun- broughbroughtt bacbackk frofromm Ceylon.Ceylon. BeforeBefore advancedadvanced berbergg andand othersothers iinn hishis dayday werweree ttoo a larglargee extentextent methodsmethods ooff chemicachemicall breakdowbreakdownn becambecamee availableavailable mitigatemitigatedd bbyy ththee successsuccess ofof chemicachemicall analyticalanalytical thertheree waswas littlelittle thathatt mineralogistmineralogistss couldcould dodo ttoo methodsmethods utilizinutilizingg alkalialkali fusionsfusions ofof hithertohitherto intract­intract­ identifidentifyy manymany speciesspecies whichwhich nethernether reactereactedd beforebefore ablablee minerals,minerals, andand fromfrom ththee fusions,fusions, nonoww water­water- ththee blowpipeblowpipe flamflamee nonorr alloweallowedd attackattack bbyy thenthen soluble,soluble, furtherfurther isolatingisolating distinctivdistinctivee compoundcompoundss -- availablavailablee acidacidss anandd reagents.reagents. usuallusuallyy oxidesoxides suchsuch asas 'silica~'silica', 'alumina~'alumina', etcetc.. AmongAmong IInn hihiss furthefurtherr discussiondiscussion ofof CeyloCeylonn gemstones,gemstones, ththee mosmostt successfulsuccessful analystanalystss aatt ththee closclosee ooff ththee 18th18th ThunberThunbergg hashas littlelittle difficultdifficultyy identifyinidentifyingg amethystamethyst centurcenturyy anandd intointo thethe firsfirstt yearsyears ofof ththee 19th19th centurycentury iinn whicwhichh thethe crystalscrystals areare characteristicallycharacteristically termin­termin­ was MartiMartinn HeinricHeinrichh KlaprotKlaprothh (1743-1817)(1743-1817),, char­char­ ated,ated, "some"some havhavee sixsix sides,sides, andand ononee hexagonalhexagonal acterizedacterized bbyy MarMaryy ElviraElvira Weeks,Weeks, Discovery of thethe pointpoint"" (p.222).(p. 222). However,However, thethe "robal'~"robal", saidsaid toto bbee Elements (Weeks,(Weeks, 1956,1956, pp.263). 263) asas "the"the mostmost disting­disting­ dark-reddark-red,, darkedarkerr thathann ruby,ruby, iiss notnot furtherfurther describeddescribed uisheduished GermanGerman mineralogicamineralogicall andand analyticalanalytical chem­chem­ andand ititss identitidentityy mustmust remainremain speculative.speculative. Thun­Thun- isistt ooff hishis time"time'~. KlaprotKlaprothh publishedpublished hihiss numerousnumerous berg'berg'ss "hyacinths""hyacinths" thathatt occuoccurr inin "small"small yellowish­yellowish- analyticalanalytical resultresultss inin variouvariouss journaljournalss bubutt thesthesee araree browbrownn oorr reddishreddish prismsprisms"" appeaappearr ttoo bbee zircons,zircons, andand foundfound convenientlyconveniently collectecollectedd inin hishis BeiträgeBeitriige zurzur thethe addeaddedd remarkremarkss onon "red"red tourmalintourmalin"" thathatt speakspeak ooff chemischen Kenntnis Kenntnis derder Mineralkorpers, Mineralkörpers, 6 6 volumes, volumes , crystalcrystalss thathatt "seem"seem ttoo havehave foufourr similarsimilar sidessides oonn 1795-1815,1795-1815, ooff whicwhichh ththee firsfirstt twotwo volumevolumess inin ththee theirtheir oblongoblong columncolumn,, andand a quadrangularquadrangular pyramid'~pyramid", EnglishEnglish editioeditionn araree utilizeutilizedd herheree (Klaproth,(Klaproth, 1801).1801). agaiagainn applapplyy besbestt ttoo zirconzircon.. SpeakingSpeaking ooff thithiss speciesspecies,, ThusThus,, onon corundumcorundum,, oorr "oriental"oriental sapphire"sapphire'~, Klap­Klap­ iitt was KlaprotKlaprothh (p(p.175. 175 ff.)ff.) whowho "discovered"discovered zirconiazirconia rothroth disputedisputess Bergman'Bergman'ss analysisanalysis,, iinn whicwhichh ththee latterlatter iinn 17891789 whilwhilee analyzinanalyzingg a zircozirconn frofromm Ceylon"Ceylon" includeincludess 3535%% silica,silica, anandd afterafter a lengthylengthy descriptiondescription (Weeks,(Weeks, pp.543),. 543), furtherfurther notingnoting colours,colours, crystalcrystal ooff hishis analyticaanalyticall procedureprocedure,, arrivearrivess atat hishis owownn formsforms,, anandd specificspecific gravitiesgravities,, bubutt givingivingg creditcredit ttoo

CORUNDUMCORUNDUM c(OOOI)c(OOOI)

SAPPHIRE RUBY

1200

^=£s PINACOIDPINACOID c, HEXAGONALHEXAGONAL PRISMPRISM* 0,, striated NEGATIVENEGATIVE RHOMBOHEDRONRHOMBOHEDRON rl0lT21r/0\\2/ HEXAGONAHEXAGONALL DIPYRA_MIDDIPYRAMIDSS n/ll~3/.tf/ll23/, z/1l21/.z/1121/, ANANDD wiw/7.7.14 7. 7. i4.. 313/

FigFig.. 22.. SapphireSapphire anandd rubyruby crystalscrystals,, thethe sapphiresapphire atat extremeextreme leftleft beingbeing particularlparticularlyy typicatypicall ooff thosethose foundfound iinn ththee gemgem grvelgrvelss ooff SriSri Lanka.Lanka. FroFromm a drawindrawingg bbyy JohnJohn SinkankasSinkankas inin hihiss Mineralogy. 468 J.J. Gemm.,Gemm0 1991,22,81991,22,8

r------, Fig.Fig. 33.. ZirconZircon crystalscrystals showingshowing commoncommon forms,forms, ththee upperupper twtwoo examplesexamples beingbeing notednoted veryvery frequentlyfrequently amongamong thethe crystalscrystals foundfound inin thethe gemgem gravelsgravels ofof SriSri Lanka.Lanka. FromFrom ,I23£ a drawingdrawing byby JohnJohn SinkankasSinkankas iinn 97 hishis MMineralogy. ineraiagy.

m (110)

ZIRCON Twin on plane 101

a

FIRSTFIRST ORDERORDER PRISMPRISM m.m, SECONDSECOND ORDERORDER PRISMPRISM <7a., FIRSTFIRST ORDERORDER DIPYRAMIDSDIPYRAMIDS p, U,u, v,v, DITETRAGONALDITETRAGONAL DIPYRAMIDDIPYRAMID x.x.

J.B.L.J.B.L. RomeRome DelisleDelisle (1736-1790)(1736-1790) forfor beingbeing thethe firstfirst crystals,crystals, isis mostmost likelylikely toto bebe zircon.zircon. TopazTopaz iiss mineralogistmineralogist toto suggestsuggest thatthat zirconzircon waswas a distinctdistinct reaffirmedreaffirmed asas genuine,genuine, andand isis saidsaid toto occuroccur "mostly"mostly species.species. KlaprothKlaproth alsoalso analyzedanalyzed hyacinthhyacinth fromfrom inin yellowishyellowish splinters'~splinters", whilewhile thethe "cinnamon-stone'~"cinnamon-stone", CeylonCeylon (p.19S),(p. 195), notingnoting againagain thatthat erroneouserroneous analysisanalysis a termterm longlong appliedapplied toto grossulargrossular fromfrom CeylonCeylon byby BergmanBergman (who(who failedfailed toto recognizerecognize thethe presencepresence ooff "derives"derives itsits namename fromfrom itsits colour,colour, whichwhich inin somesome zirconia)zirconia) andand determiningdetermining thatthat chemicallychemically itit waswas thethe measuremeasure resemblesresembles thethe oiloil drawndrawn fromfrom thethe besbestt andand samesame asas zircon.zircon. finestfinest cinnamon"cinnamon" (p.22S).(p. 225). Thunberg'sThunberg's "blue"blue saphire"saphire"ma mayy alsoalso bebe misidenti­misidenti- TheThe "yellow"yellow tourmalin"tourmalin" was nevernever seenseen inin crystalscrystals fiedfied becausebecause allall specimensspecimens thatthat hehe sawsaw areare claimedclaimed toto byby ThunbergThunberg butbut onlyonly inin alluvialalluvial stonesstones "always"always bbee moremore uniformlyuniformly colouredcoloured thanthan amethysts,amethysts, "al"alll wornworn smooth...smooth... fromfrom thethe sizesize ofof a graingrain ofof ricerice ttoo thosethose whichwhich I sawsaw hadhad beebeenn wornworn smoothsmooth byby theirtheir thatthat ofof a pea':pea". NothinNothingg furtherfurther isis givengiven asas anan aidaid ttoo agitationagitation iinn thethe water"water'~, andand "all"all mademade useuse of,of, whenwhen thethe identificationidentification ofof thisthis gemstone.gemstone. TheThe so-calledso-called cut,cut, forfor buttonsbuttons andand rings':rings". ThisThis descriptiondescription seemsseems "white"white tourmalin'~tourmalin", alsoalso calledcalled "Maturese"Maturese diamond"diamond" unlikelyunlikely forfor trutruee sapphiresapphire butbut couldcould bebe applicableapplicable toto fromfrom thethe towntown ofof MataraMatara isis certainlycertainly zirconzircon anandd iolite,iolite, aquamarine,aquamarine, oror topaz.topaz. HeHe repeatsrepeats hishis previousprevious ThunbergThunberg providesprovides somesome ofof ourour earliestearliest knowledgeknowledge statementstatement thatthat "blue"blue tourmalin"tourmalin" isis nothingnothing bubutt ofof heaheatt treatmenttreatment ofof gemstonesgemstones toto improveimprove theirtheir quartzquartz withwith a tingetinge ofof blue.blue. OnOn thethe otherother hand,hand, a colourcolour whenwhen hehe statedstated thatthat thisthis stonestone iiss "almost"almost greengreen sapphiresapphire isis reaffirmedreaffirmed asas "geniune'~"geniune", whilewhile thethe alwaysalways thethe colourcolour ofof milk,milk, soso thatthat itsits transparencytransparency isis "green"green tourmalin'~tourmalin", againagain fromfrom hishis descriptiondescription ofof itsits notnot perfectlyperfectly clear.clear. ForFor thisthis reasonreason itit isis frequentlyfrequently J.Gemm., 1991,22,8 469

calcined in the fire, in consequence of which the was 2.625 as compared to 2.660 for a cut cat's-eye colour vanishes, and the stone becomes much from Ceylon, and from the analyses established the clearer, although not perfectly white. It is then material as almost pure silica (Klaproth, p. 78 ff). enveloped in fine lime, and burned with rice-chaff Despite the evidence of hardness and irregular, (oryza)." This is "Matara diamond" or colourless splintery fracture, Klaproth suggested that "it zircon known for hundreds of years by that name in would be more proper, in my opinion, to class it the gem trade. with the opals; among which also it was formerly As to other stones in Thunberg's list, the "white reckoned under the names of Pseudopal, Cat's-eye- crystal", is ordinary rock crystal, but "water- opal"(p.84). saphire" is certainly neither corundum nor iolite; Thunberg ends his amplifying remarks by noting under the above misnomer it has for many years that "the stone known in Europe under the name of masqueraded as corundum but here appears to be Tourmalin, and celebrated for its electrical virtues, nothing more than a colourless zircon. Thunberg is not known by the same name by the Indians; but says it very much resembles the white crystal but is that they denote by the word Tourmalin, several clearer and "is especially distinguishable by its stones, which possess not electrical properties, and hardness, in which it surpasses the Crystals." While which are even of different species, of different this suggests corundum, Thunberg admits that he colours, and of different degrees of transparency". never could obtain any of these stones as crystals Regarding the genuine tourmaline of Ceylon, its but only as "shapeless pieces, or else flat and pyroelectrical properties had been known long rounded off, with rugged surface, full of small before Thunberg's collection of same as pointed out impressions like dots." Passing on to other "crys­ by R.W. Home (Aepinus, 1979) who notes that tals" the kind called "taripo" is defined as milky "samples of this stone had begun to be imported quartz, while the yellow and brown crystals corres­ into Europe from Ceylon in the early years of the pond to our citrine and smoky quartzes. But in the eighteenth century for use in jewelry. The Dutch same breath Thunberg mentions "black crystal" and German jewelers who for many years enjoyed a which now appears to be schorl because he notes virtual monopoly over the tourmaline trade soon that some crystals display "six dissimilar sides and discovered in working them that their stones pos­ an obtuse triangular point," a fair description for sessed the remarkable property of attracting a many of the black to brown or reddish-brown coating of ash to themselves as they were heated in strongly dichroic tourmaline crystals commonly the fire". Thunberg's tourmaline specimens, in part, found in Sri Lankan gem gravels, and in shape were turned over to his celebrated compatriot, ranging from smooth ovate pebbles to some which Torbern Olof Bergman (1735-1784), chemist, are stubby prisms, doubly-terminated, to some mineralogist, pharmacist and professor in the uni­ which are practically compressed to wafer-like versity at Uppsala, who investigated them to the shapes with scarcely more than traces of prism best of his ability and resources and then published faces. Thunberg notes that he "could not observe, the first adequate analysis of same and at the same that the Indians were acquainted with its electrical time remarking on the strong dichroism, variations properties, which they never denote by the name of in properties, and crystal habits (Bergman, 1784). It Tourmalin, but bestow that denomination upon was to Bergman that Thunberg turned for aid in several other species". identifying his Ceylon treasures, acknowledging One of the stones on the list is the cat's-eye called that he "very kindly furnished me with their a "pseudo-opal", which is neither chrysoberyl nor mineralogical names" (Thunberg, 1795, p. 229). opal, but chatoyant quartz. He describes the stone In conclusion it is noted that another early report as "a very hard stone, which approaches more or on Ceylon's minerals appeared in an article by John less white or green, and is semi-diaphanous, with a W. Webster who summarized a report by Dr John streak the breadth of a line in the middle, which Davy, of England, that originally appeared in the streak is much whiter than the stone itself, and fifth volume of the Transactions of the Geological throws its light to whatsoever side this is turned. In Society of London (Webster, 1824). Davy noted that this respect therefore it resembles a cat's-eye, topaz is called "white sapphire" in Ceylon, that whence it derives its name". The largest piece he tourmaline is rare and met with by him only in saw was the size of a hazel nut. From further honey-yellow specimens, and that cinnamon-stone remarks it is plain that it is not chrysoberyl, the garnet, although abundant, is found only in two term "pseudo-opal", apparently being used in his places, namely Cotta and Belligam. He also noted time to describe certain varieties of quartz which that zircons of the Matara district receive the name bore some fancied resemblance to opal. In fact, "Matara diamonds" for their finest varieties. Davy Klaproth, who analyzed a specimen from "the claimed that "the natives of Ceylon are perfectly coasts of Malabar", noted that its specific gravity ignorant of the true nature of zircon, and sell the 474700 JJ.. Gemm.Gemm.,3 1991,22,81991,22,8

yelloyelloww varietievarietiess aass topazetopazess ooff a peculiapeculiarr kindkind,, ththee Transl.Trans!. frofromm ththee originaoriginall LatiLatinn ooff SiSirr TorberTorbernn Bergman… ... bbyy greegreenn aass tourmalinestourmalines,, ththee reredd aass rubiesrubies,, anandd ththee lighlightt EdwarEdwardd CullenCullen.. LondonLondon:: JJ.. MurrayMurray.. EspEsp.. DissertatioDissertationn XVIXVI,, oonn CeyloCeylonn tourmalinetourmaline,, p.120-33p.120-33.. gregreyy aass diamondsdiamonds"" (Webster(Webster,, 56)56).. IInn 18231823,, J.LJ.L.. BournonBournon,, J.L.J. L.,, 18231823.. Observations sursur quelques-uns des MMinéraux, ineraux, BournoBournonn (1751-1825)(1751-1825),, ththee FrencFrenchh mineralogismineralogistt soitsoit dede l'Ilel'Ile dede Ceylan. LondresLondres:: CheChezz DulauDulau.. (henc(hencee bournonite), examinedexamined andand describeddescribed spinelsspinels CassonCasson,, L.L.,, 19891989.. The Periplus Maris Erythraei.Erythraei. TexTextt witwithh frofromm CeylonCeylon,, anandd suggestesuggestedd possiblpossiblee originoriginss ooff ththee introduction,introduction, translation, translation, and commentary and commentary by Lionel byCasson. Lionel Cas­ son. PrincetoPrincetonn UniversitUniversityy PressPress,, PrincetonPrinceton,, NJNJ.. alluviaalluviall gemstonegemstoness ofthaof thatt islandisland,, basinbasingg hihiss remarkremarkss Gübelin,Giibelin, E., E., 1968. 1968. Der Der Edelsteine Edelsteine der Inselder InselCeylon. Ceylon. Gübelin: Giibelin: oonn ththee reportreportss oofJ.B.L.c.f J.B.L.C.T T.. LeschenaulLeschenaultt DDee LatouLatourr LucerneLucerne.. (1773-1820(1773-1820)) whwhoo visitevisitedd ththee islanislandd anandd ththee coascoastt ooff KlaprothKlaproth,, M.H.M.H.,, 18011801.. Analytical Essays towardstowards Promoting thethe CoromandeCoromandell (Bournon(Bournon,, 1823)1823).. Chemical Knowledge of Mineral Substances. TT.. CadellCadell,, LondonLondon.. TavernierTavernier,, J.B.J.B.,, 16761676.. Les sixsix voyages .….. GervaiGervaiss ClouzierClouzier,, ParisParis,, AcknowledgemenAcknowledgementt 3 vo!'vol. TavernierTavernier,, J.BJ.B.. (V(V.. Ball)Ball),, 18891889.. Travels in IndiaIndia by Jean BaptisteBaptiste MMyy sincersinceree thankthankss araree extendeextendedd ttoo DDrr KurtKurt Tavernier… . .. translatetranslatedd frofromm ththee originaoriginall FrencFrenchh editioeditionn o0ff BoströmBostrom,, ooff ththee GeologicaGeologicall InstitutioInstitutionn ooff ththee UniUni­­ 1676… ... 2 volvo!'. MacMillanMacMillan,, LondonLondon.. A seconsecondd editionedition,, editeeditedd versitversityy ooff StockholStockholmm foforr obtaininobtainingg ththee photographicphotographic bbyy WW.. CrookeCrooke,, appeareappearedd iinn 2 volvo!'. iinn 19251925.. reproductioreproductionn ooff ththee portraiportraitt paintinpaintingg ooff ThunbergThunberg ThunbergThunberg,, C.P.C.P.,, 1795-61795-6.. Travels inin Europe, Africa, and Asia,Asia, anandd foforr hihiss encouragemenencouragementt iinn completincompletingg thithiss madmadee betweebetweenn ththee yearyearss 17717700 anandd 1779… ... BByy CharleCharless PetePeterr ThunbergThunberg.. 4 volsvols.. CC.. RivingtonRivington,, LondonLondon.. FirsFirstt editedit.. UpsalUpsalaa projectproject.. 1788-931788-93;; otheotherr editsedits.. iinn FrencFrenchh anandd GermanGerman.. WebsterWebster,, J.W.J.w.,, 18241824.. GeologGeologyy anandd mineralogmineralogyy ooff CeylonCeylon.. Boston JournalJournal of Philosophy and thethe Arts, Vo!.Vol. I,I, Boston.Boston. p.53-9.p.53-9. ReferenceReferencess WeeksWeeks,, M.E.M.E.,, 1956.1956. Discovery of the Elements. 6t6thh eded.. editedit,, bbyy AepinusAepinus,, F.U.TF.U.T.. (Hom(Homee & Connor)Connor),, 19791979.. Aepinus's Essay on the H.MH.M.. LeicesterLeicester.. JournaJournall ooff ChemicaChemicall EducationEducation,, Easton.Easton. Theory ofof Electricity Electricity and and Magnetism. Magnetism. Introductory Introductory monograph mono­ pp.263pp.263,543., 543. graph anandd notenotess bbyy R.WR.W.. HomeHome;; transltrans!'. bbyy P.JP.J.. Connor.Connor. YuleYule,, H.H.,, 1871.1871. The Book ofofSerMarcoPolo, Ser Marco Polo, the Venetian. NewlyNewly Princeton U. U. Press, Press, Princeton, Princeton, NJ. NJ.p.92-3 p.92-3 esp. esp. translatetranslatedd anandd editeeditedd witwithh notenotess bbyy ColoneColonell HenrHenryy YuleYule.. 2 BauerBauer,, MM.. (Spencer)(Spencer),, 19041904.. Precious Stones. TranslTrans!.. bbyy L.J.L.J. volsvols.. JohJohnn MurrayMurray,, LondonLondon.. IIII,, p.254-6p.254-6.. SpencerSpencer.. CharleCharless GriffinGriffin,, London.London. BergmanBergman,, T.OT.O.. (Cullen)(Cullen),, 17841784.. Physical and Chemical Essays.Essays. [[ManuscriptManuscript received 14 March 1991991. I.J] J.J. Gemm.,Gemm., 1991,22,81991,22,8 471471

TheThe microscopicmicroscopic determinationdetermination ofof structuralstructural propertiesproperties forfor thethe characterizationcharacterization ofof opticaloptical uniaxialuniaxial naturalnatural andand syntheticsynthetic gemstonesgemstones PartPart 3:3: ExamplesExamples forfor thethe applicabilityapplicability ofof structuralstructural featuresfeatures forfor thethe distinctiondistinction ofof naturalnatural andand syntheticsynthetic sapphire,sapphire, ruby,ruby, amethystamethyst andand citrinecitrine (1) (2) Dipl.-Min Lore Kiefert (I)and and Dr Karl Schmetzer(2)Schmetzer

(1) (1) Griffith University, Queensland, AustraliaAustralia (2) (2) MarbacherStr.Marbacher Str. 22b, D-8067 Petershausen, Germany

AbstractAbstract che, nigerianische,nigerianische, kamobschanischekamobschanische undund thailandischethailändische TheThe applicationapplication ofof diagnosticdiagnostic growthgrowth structuresstructures forfor Sapphire),Sapphire), ChathamChatham synthetischesynthetische Sapphire,Sapphire, natiirlichenatürliche the distinctiondistinction of ofnatural natural and andsynthetic synthetic optically optically uniaxial unia­ RubineRubine ausaus Malawi,Malawi, KnischkaKnischka synthetischesynthetische Rubine,Rubine, xial gemgem mineralsminerals suchsuch asas corundumcorundum andand quartzquartz isis sowohlsowohl natiirlichenatürliche AmethysteAmethyste undund CitrineCitrine verschiedenerverschiedener discussed.discussed. TypicalTypical examplesexamples forfor thethe characterizationcharacterization ofof Herkunft,Herkunft, wiewie auchauch vonvon verschiedenenverschiedenen HerstellernHerstellern naturalnatural gemgem varietiesvarieties ofof corundumcorundum andand quartzquartz areare geziichtetegezüchtete AmethysteAmethyste undund Citrine.Citrine. quoted, e.g. e.g. sapphires sapphires and and rubies, rubies, amethysts amethysts and citrines and cit­ rines fromfrom distinctdistinct sourcessources areare describeddescribed byby meansmeans ofof ResumenResumen growth structures. structures. In Inaddition, addition, their their synthetic synthetic counterparts counter­ SeSe discutediscute lala aplicacionaplicación dede marcasmarcas ddee crecimientocrecimiento parts ofof somesome producersproducers areare comparedcompared usingusing structuralstructural diagnosticas para para la ladistinción distincion entre entre minerales minerales de calidad de cali­ featuresfeatures ofof diagnosticdiagnostic value.value. Criteria,Criteria, whichwhich areare usefuluseful dad gemagema naturalesnaturales 0o sinteticossintéticos queque sonson opticamenteopticamente forfor thethe recognitionrecognition ofof facetedfaceted gemstonesgemstones asas naturalnatural oror uniaxicos,uniaxicos, talestales comocomo elel corindoncorindón y elel cuarzo.cuarzo. SeSe facilitanfacilitan syntheticsynthetic areare underlined.underlined. GemGem materialsmaterials describeddescribed inin ejemplosejemplos tipicostípicos parapara lala caracterizacioncaracterización dede variedadesvariedades detaidetaill areare naturalnatural sapphiressapphires fromfrom alkalinealkaline hosthost rocksrocks naturalenaturaless dede calidadcalidad gemagema dede corindoncorindón y cuarzo;cuarzo; porpor (Australian,(Australian, NigerianNigerian,, CambodianCambodian andand ThaiThai sapphires),sapphires), ejemplo,ejemplo, sese describendescriben mediantemediante elel ususoo dede marcasmarcas dede Chatham synthetic synthetic.sapphires, sapphires, natural natural rubies rubies from from Malawi, Mala­ crecimientocrecimiento zafiroszafiros y rubies,rubíes, amatistasamatistas y cuarzoscuarzos citrinoscitrinos wi, KnischkaKnischka syntheticsynthetic rubies,rubies, naturanaturall amethystsamethysts andand dede determinadosdeterminados yacimientos.yacimientos. Ademas,Ademas, sese comparancomparan citrinescitrines fromfrom differentdifferent sourcessources asas wellwell asas syntheticsynthetic entreentre sisi muestrasmuestras sinteticassintéticas dede algunosalgunos fabricantesfabricantes dede amethysts and and citrines citrines from from different different producers. producers. estas gemasgemas haciendo haciendo uso uso de caracteristicasde caracteristicas estructurales estructur­ ales dede valorvalor diagnostico.diagnóstico. SeSe subrayansubrayan criterios,criterios, queque sonson ZusammenfassungZusammenfassung utilesútiles parapara distinguirdistinguir entreentre gemasgemas talladastalladas naturalesnaturales 0o Die AnwendungAnwendung von von Wachstumsstrukturen Wachstumsstrukturen zur Unterscheidungzur Un­ sintéticas.sinteticas. Se Se describe describe con con detalle detalle los lossiguientes siguientes materials mater­ terscheidungnatürlicher und natiirlicher synthetischer und Edelsteinminerale synthetischer Edelstein­ iales dede calidadcalidad gema;gema; loslos zafiroszafiros naturalesnaturales concon origenorigen enen minerale mitmit einereiner optischenoptischen Achse,Achse, wiewie KorundKorund undund rocas alcalinas (Australia, (Australia, Nigeria, Nigeria, Cambodia Cambodia y Thailandia), y Thailan­ Quarz wird wird beschrieben. beschrieben. dial, zafiroszafiros sinteticossintéticos dede Chatham,Chatham, rubiesrubies naturalesnaturales dede TypischeTypische BeispieleBeispiele zurzur CharakterisierungCharakterisierung natiirlichernatürlicher Malawi,Malawi, rubiesrubies sinteticossintéticos dede Knischka,Knischka, amatistasamatistas y EdelsteinartenEdelsteinarten vonvon KorunKorundd undund QuarzQuarz werdewerdenn erwaht,erwäht, cuarzoscuarzos citrinoscitrinos naturalenaturaless dede distintosdistintos yacimientosyacimientos alal u.a.u.a. SapphireSapphire undund Rubine,Rubine, AmethysteAmethyste undund CitrineCitrine igualigual queque amatistasamatistas y cuarzoscuarzos citrinoscitrinos sinteticossintéticos dede verschiedenerverschiedener HerkunftHerkunft werdenwerden beschriebebeschriebenn anan HandHand distintos fabricantes. fabricantes. derder Wachstumsstrukturen.Wachstumsstrukturen. AuBerdemAußerdem werdenwerden diedie synthetischesynthetische GegenstiickeGegenstücke einiger Hersteller mit einander verglichen mittels struk­ einiger Hersteller mit einander verglichen mittels struktureller I.I. IntroductionIntroduction turellerMerkmale Merkmale diagnostischer diagnostischer Art. Art. InIn thethe firstfirst parpartt ofof thisthis publicatiopublicationn (Kiefert(Kiefert & NiitzlicheNützliche KriterienKriterien zurzur ErkennungErkennung geschliffenergeschliffener EdelsteineEdelsteine alsals natiirlichnatürlich oderoder synthetischsynthetisch werdenwerden betont.betont. Schmetzer,Schmetzer, 1991a)1991a) a detaileddetailed descriptiondescription ofof AusfiihrlichstAusführlichst beschriebene beschriebene Edelsteine Edelsteine sind natürlichesind natiir­ methodsmethods forfor thethe determinationdetermination ofof characteristiccharacteristic licheSapphire Sapphire ads alkalinenads alkalinen Muttergesteinen Muttergesteinen (australische, (australis- crystalcrystal facesfaces andand growthgrowth structuresstructures inin facetedfaceted 472 J. Gemm., 1991, 22, 8

optical uniaxial gemstones by use of two simple growth planes of sapphires from alkaline rocks auxiliary means is given. In the second part of this there is nearly always a strong blue, greenish-blue, paper (Kiefert & Schmetzer, 1991b), the character­ bluish-green or yellowish-green colour zoning ization of natural and synthetic emeralds by the use observable. However, the crystal faces, especially of growth structures and their application to prac­ those of the dominant forms mentioned above, vary tical problems of determinative gemmology is dis­ markedly according to their sizes for samples of cussed in detail. different occurrences. Compared with sapphires This third part of the publication will reveal some from other types of host rocks, e.g. sapphires from new examples for the application of the methods Sri Lanka,_the appearance of the hexagonal dipyr- described in the first part, e.g. for the characteriza­ amid z {2241} is only observable in sapphires from tion of natural sapphires originating from alkali alkaline rocks in this significance [Figures 46-57]. basalts or for the characterization of the most recent Australian rough crystals, for example, show type of Knischka synthetic rubies. Additionally, a pyramidal habit with the hexagonal dipyramid z summary of results obtained by these methods, part {2241} as dominant form. The basal pinacoid c of them already published in earlier issues of this {0001} is very small in these samples. The positive journal, is presented, e.g. the recognition of rhombohedron r {1011} as well as the hexagonal Chatham synthetic sapphires or the distinction of dipyramid n {2243} appear less frequently. Corres­ natural and synthetic amethysts and citrines. ponding to this morphology, the dominant growth Figures 1-15 as well as Tables 1-3, which are planes determined in the microscope with the_above occasionally referred to in this third part of the mentioned methods occur parallel to z (2241). In publication, are presented in the first part (Kiefert addition,1 growth planes parallel to the positive & Schmetzer, 1991a). rhombohedron r (1011) as well as parallel to the basal pinacoid c (0001) are observed. Other growth II. Natural sapphires from alkaline rocks planes such as faces parallel to the hexagonal In connection with systematic investigations of dipyramids w (1121) and n (2243) appear occa­ sapphires from different localities, a great number sionally, facesj)arallel to the second-order hexagon­ of faceted sapphires and rough crystals from alka­ al prism a (1120)_as well as parallel to the hexagonal line rocks as sources have been at the authors' dipyramids v (4481) and v (4483) are extremely rare disposal. The sapphires originating from alkaline [Figures 46-49, 51, 53, 55, 57]. source rocks were of Australian, Nigerian, Cambo­ For rough crystals of Nigerian sapphires, which dian and Thai origin (cf. Vichit et ai, 1978; Jobbins showed well developed crystal faces, a typical & Berrangé, 1981; Keller, 1982; Coldham, 1985; morphology was determined as follows: the major­ Kiefert & Schmetzer, 1987). During these inves­ ity of the crystals reveal tabular habit with the basal tigations the authors discovered a significant simi­ pinacoid c {0001} and the hexagonal dipyramid z larity in structural properties of sapphires originat­ {2241} or with the crystal faces c, z and the positive ing from alkaline rocks, i.e. in most cases from rhombohredon r {lOTl}. In addition to the crystal alkali basalts. By measuring the crystal faces of the faces mentioned above, sapphires with barrel- rough samples and comparing these common mor­ shaped habit reveal the hexagonal dipyramid n phological properties with internal growth struc­ tures determined by the methods described, a Fig. 46. Growth structures in natural sapphire from Australia; correspondence between the external crystal faces planes parallel to c (0001) and r (1011). View perpen­ and the internal growth structures was proven for dicular to the c-axis, the c-axis runs vertically. Crossed all sources. Another common feature of all sap­ polarizers. 16x. phires originating from alkaline rocks are their Fig. 47. Growth structures in natural sapj)hire from Australia; spectroscopic properties, which were found to be planes parallel to c (0001), n (2243) and z (2241). View similar or almost identical for all samples from perpendicular to the c-axis, the c-axis runs vertically. different localities examined (cf. Kiefert & Schmet­ Crossed polarizers. 16x. zer, 1987; Schmetzer, 1987a). Fig. 48. Growth structures in natural sapphire from Australia; All rough crystals from alkaline rocks reveal the planes parallel to c (0001) and r (1011). View perpen­ basal pinacoid c {0001} and the hexagonal dipyr- dicular to the c-axis, the c-axis runs almost vertically. Crossed polarizers. 16x. Figs. 46 and 47 as well as Figs. amid z {2241} as dominant forms, and the positive 47 and 48 are related by a rotation of 30° about the rhombohedron r {1011} appears frequently. Sub­ c-axis, Figs. 46 and 48 are related by a rotation of 60° ordinate forms, e.g. some other pyramidal faces or about the c-axis. the hexagonal prism, differ only slightly from locality to locality [cf. Figures 3a, d]. The above Fig. 49. Growth structures in natural samphire from Australia; planes parallel to c (0001), n (2243) and z (2241). View mentioned three crystal faces dominate in cut perpendicular to the c-axis, the c-axis runs diagonally samples as growth planes. In connection with from lower left to upper right. Crossed polarizers. 20x. J.J . Gemm.,Gemm, 1991,22,81991,22,8 473473

Pig. 46.

FigPig.. 4848.. FigFig.. 4949.. 474 J. Gemm, 1991,22,8

{2243} [Figure 3a]. Crystals with prismatic habit positive rhombohedron rjlOTl}, the second-order display the hexagonal prism a {1120} in addition to hexagonal prism a {1120}- as well as different the forms mentioned above [Figure 3d]. The deter­ hexagonaldipyramids n {2243}, w{l\2l},v {4483} mination of growth structures in the microscope by and v {4481} may occur as more or less subordinate use of the methods described, reveals that the forms. Sapphires from alkaline rocks often occur growth planes are, according to the morphology of with a thick tabular habit, but barrel-shaped, the rough crystals, mainly parallel to dominant pyramidal or prismatic crystals were also found, and crystal faces like the hexagonal dipyramid 2_(2241), sapphires with a habit intermediate between these parallel to the positive rhombohedron r (1011) and three basal morphologies were also examined. parallel to the hexagonal dipyramidn (2243) and At present, nohexagonal dipyramids with the parallel to the hexagonal prism a (1120) may occur exception of n (2243) and no second-order hexagon­ [Figure 54, see also Kiefert & Schmetzer, 1987]. al prisms a (1120) were observed as crystal faces of Cambodian sapphires available to the authors flux-grown synthetic sapphire (cf. section III). disclosed very rarely well developed crystal faces. Thus, the presence of at least one of these growth The few crystals with preserved external morpholo­ structures indicates a sapphire of natural origin. gy are described as follows: the majority of these Among several hundreds of faceted samples ex­ samples reveal tabular habit with the basal pinacoid amined, part of them without characteristic mineral c {0001} and the hexagonal dipyramid z {2241}, inclusions, each of those natural sapphires originat­ occasionally the positive rhombohedron r {1011} is ing from alkaline rocks disclosed characteristic observed. This morphology corresponds to the growth structures and, consequently, were deter­ morphology of part of the Nigerian sapphires [cf. minable' as natural using the above mentioned Figures 3a, d]. Besides these forms part of the criteria. Cambodian sapphires reveal pyramidalhabit with only the hexagonal dipyramid z {2241} as the III. Growth structures and twinning in flux-grown crystal form. Occasionally tabular crystals with the Chatham synthetic blue sapphires second-order hexagonal prism a {1120} and the All different syntheses of corundum produced by basal pinacoid c {0001} appear. In accordance with the flux method show a distinct, limited number of the examination of sapphires from Australia and crystal faces, which are easily determinable with the Nigeria, the determination of internal growth struc­ methods described by the authors. Due to the tures of Cambodian sapphires in the microscope composition of the flux as well as other variable reveals that the most frequently appearing growth growth conditions, which are applied for the pro­ planes correspond to the external morphology of duction of the individual synthesis, the number of thecrystals. These are the hexagonal dipyramid z crystal faces vary for the different commercial (2241) as well as the basal pinacoid c (0001). As productions of corundum. For example, the com­ subordinate growth planes the positive rhom­ mon crystal faces of Chatham synthetic rubies are c, bohedron r_ (1011), the second-order hexagonal r, d, and n [cf. Table 1]. In rubies made by Kashan c, prism a ( 1120)_as well as the hexagonal dipyramids n r, and n appear as crystal faces, and Knischka (2243), w (1121), v (4483) and v (4481) could be synthetic rubies reveal the crystal faces c, r, d, w, and determined [Figure 50]. y. The morphology of synthetic rubies produced by Among the investigated sapphires from Thai­ Ramaura consists of c, r, and d (cf. Schmetzer, land, no rough crystals with well developed crystal 1986). faces were available. However, similar to the sap­ An important feature for the distinction of natu­ phires from the occurrences mentioned above, the ral and synthetic rubies is the absence of prism and dominant growth planes inthe microscope are the some pyramidal faces in synthetic stones, whereas hexagonal dipyramid z (2241) and the basal pina­ the negative rhombohedra d and y never appear in coid c (0001). The frequency of other appearing natural samples (cf. Schmetzer, 1986). growth planes is similar to that of Cambodian Flux-grown Chatham synthetic sapphires are sapphires. The crystal faces observedare occa­ described here in some detail and will be compared sionally the positive rhombohedron r(10Tl) and the with natural sapphires from alkaline rocks (cf. hexagonal dipyramid w (1121), and, less frequently, section II). For the investigation of structural the hexagonal dipyramids n (2243)_and v (4483) as properties of Chatham synthetic blue sapphires, well as the hexagonal prism a (1120) [Figures 52, both rough crystals and faceted stones were avail­ 56]. able (cf. Kiefert & Schmetzer, 1988). The rough In summary, the morphology of all natural samples were found to consist of single crystals and sapphires originating from alkaline rocks is domin­ twinned individuals. Twinning is easily recogniz­ ated by the basal pinacoid c {0001} and the able due to the re-entrant angles of the samples. The hexagonal dipyramid z {2241}. In addition, the crystal faces which were identified in both untwin- J. Gemm., 1991,22,8 475

Fig. 50. Growth structures in natural sapphire from Pailin, Cambodia; planes parallel to c (0001) and r (1011). View perpendicular to the c-axis, the c-axis runs vertically. 25x.

Fig. 51. Growth structures in natural sapphire from Australia; planes parallel to c (0001), n {2243} and z {2241}. View Fig. 52. Angled growth structure in natural star-sapphire from perpendicular to the c-axis, the c-axis runs vertically. Thailand; planes parallel to the hexagonal prism faces Crossed polarizers. 20x. a and a' {1120} form an angle of 120°. View parallel to the c-axis. Crossed polarizers. 26x.

Fig. 53. Angled growth structure in natural sapphire from Fig. 54. Angled growth structure in natural sapphire from Australia; planes parallel to the hexagonal dipyramids Nigeria; planes parallel to the hexagonal dipyramids z z and z' {2241} form an angle of 121.1°. View 10.4° and z* {2241} form an angle of 121.1°. View 10.4° inclined to the c-axis. 20 x. inclined to the c-axis. 25x. 476 J. Gemm., 1991, 22, 8

ned and twinned crystals are identical, the samples supposed to be similar to the production of flux- displayed tabular to rhombohedral habit with the grown Chatham synthetic rubies. According, to basal pinacoid c {0001}, the positive rhombohedron their morphology, both syntheses are most probably r {lOTl}, the negative rhombohedron d {0112} and produced by using the same or almost identical the hexagonal dipyramid n {2243} as predominant compositions of fluxes, which was confirmed by forms, as well as the negative rhombohedron y chemical investigations of residual flux material in {0115} as subordinate form [Figures 3b, c, f]. rough and faceted samples. Both syntheses, ruby Occasionally, an oscillatory development of both and sapphire, reveal twinning across (1010), which negative rhombohedra d and y was observed caus­ is not known for natural corundum. The only ing parallel striations on these crystal faces. No difference between Chatham synthetic ruby and prism faces were detected. All single and repeatedly Chatham synthetic sapphire is the occurrenceof twinned individuals (cyclic twinning) were contact small faces of the negative rhombohedron y (0115) twins with the second-order hexagonal prism a in synthetic sapphire, which so far was not found in {1120} as composition plane and the first-order synthetic ruby. hexagonal prism m {1010} as twin plane [Figure IV. Natural ruby from Malawi In the immersion microscope, families of straight Corundum from Malawi was already mentioned parallel growth planes were determined which in earlier publications (Rutland, 1969; Grubessi & reflect the external morphology of the crystals. Marcon, 1986), but in recent months larger quanti­ These growth faces are parallel to the predominant ties of high quality rubies from this source have external forms, i.e. parallel to c (0001), r (1011),

Fig. 55. Angled growth structure in natural sapphire from Fig. 56. Angled growth structure in natural sapphire from Australia; planes parallel to the hexagonal dipyramids Thailand; planes parallel to r (1011), n and n' {2243} w and w' {1121} form an angle of 124.0°. View 20.1° form angles of 154.0°. View about 30° inclined to the inclined to the c-axis. c-axis. 30x.

Fig. 58. Growth structures and twinning in flux-grown Fig. 59. Growth structures and twinning in flux-grown Chatham synthetic sapphire;_growth sectors confined Chatham synthetic sapphire; repeated twinning across to the rhombohedron r (J_011) [right part] and the {1010} with two composition planes a and a' {1120} hexagonal dipyramid n (2243) [leftpart] are divided by observable. View parallel to the c-axis. 24x. a twin boundary parallel to a (1120). View about 30° inclined to the c-axis. 40x. 478 J. Gemm., 1991,22,8

Fig. 57. Angled growth structure in natural sapphire from Fig. 60. Twinning in flux-grown Chatham synthetic sapphire; Australia; planes parallel to r (1011) and n (2243) form intercalated lamellae of corundum in twin position on r an angle of 154.0°. View about 30° inclined to the (1011). View 32.4° inclined to the c-axis. 40x. c-axis. 30x.

Fig. 61. Angled growth structure in natural ruby from Malawi; Fig. 62. Growth structure in naturaljuby from Malawi; planes planes parallel to the hexagonal prism faces a and a' parallel to c (0001) and r (1011). View perpendicular to {1120} form an angle of 120°. View parallel to the the c-axis, the c-axis runs vertically. 20x. c-axis. Crossed polarizers. 16x.

Fig. 63. Growth structure in natural ruby from Malawi; planes Fig. 65. Growth structures in Knischka synthetic ruby_; oscil­ parallel to c (0001), n (2243) and a (1120). View lating planes parallel to n (2243) and n (2243) form perpendicular to the c-axis, the c-axis runs almost angles of 122.4°. View perpendicular to the c-axis, the vertically. 26x. Figs. 62 and 63 are related by a rotation c-axis runs vertically. 35x. of 30° about the c-axis. JJ.. Gemm.Gemm.,, 19911991,22,8, 22, 8 474799

revealthreveal thee crystacrystall facefacess c {0001}{OOOI},, rr {{WIl},1011}, d {0112}{OlI2},, n {2243{2243}} anandd y {0115{OlI5}} andand,, consequentlyconsequently,, shoshoww a certaicertainn similaritsimilarityy ttoo ChathaChathamm synthetisyntheticc sapphiressapphires anandd rubierubiess [cf[ef.. FigureFiguress 3b3b,, ff;; seseee alsalsoo GaliaGalia,, 1987]1987].. TherTheree isis,, howeverhowever,, a diagnostidiagnosticc featurfeaturee commonlycommonly observeobservedd iinn alalll generationgenerationss ooff KnischkKnischkaa syntheticsynthetic rubiesrubies,, whicwhichh iiss duduee ttoo ththee compositiocompositionn ooff ththee flux, parpartt ooff whicwhichh alwayalwayss containcontainss a certaicertainn percentagpercentagee ooff a tungsten-bearintungsten-bearingg compouncompoundd (cf(ef.. Schmetzer,Schmetzer, 1987b). ThiThiss diagnostidiagnosticc featur featuree ooff ththee syntheticsynthetic rubierubiess madmadee bbyy KnischkKnischkaa iiss ththee oscillatoroscillatoryy growtgrowthh ooff the_second-ordethe second-orderr hexagonahexagonall dipyramiddipyramidss n {2243{2243}} anandd 11n {2243}{2243},, causincausingg paralleparallell striationstriationss oonn ththee externaexternall crystacrystall facefacess (cf(cf.. KnischkKnischkaa &^Zirkl& Zirkl,, 1986)1986).. IIff thesthesee oscillatoroscillatoryy striationstriationss ooff nnand and 11n becombecomee ververyy densedense,, ththee externaexternall habihabitt ooff ththee crystalcrystalss iiss similasimilarr ttoo prismaticprismatic,, i.ei.e.. a densdensee repititiorepititionn ooff nnand and n11 cacann simulatsimulatee ththee presencpresencee ooff ththee second-ordesecond-orderr hexagon­hexagon­ Fig. 64. Rough crystal of Knischka synthetic ruby of the most aall prisprismm a (1120)(1120).. recenrecentt commerciacommerciall productioproductionn revealinrevealingg columnacolumnarr A neneww typtypee ooff commerciacommerciall productioproductionn ooff KnisKnis­­ habithabit.. PhotPhotoo bbyy courtescourtesyy ooff ththee producerproducer.. chkchkaa synthetisyntheticc rubierubiess hahass beebeenn growgrownn sincsincee autumnautumn 19861986 anandd marketemarketedd sincsincee abouaboutt 19871987 (Knischka,(Knischka, heat-treateheat-treatedd naturanaturall amethysamethystt (citrine(citrine)) examinedexamined,, 1989).1989). AAnn importanimportantt componencomponentt ooff ththee flux iinn thithiss onlonlyy ththee positivpositivee rhombohedrorhombohedronn r (1011(IoIl)) oorr thethe productioproductionn iiss stilstilll a tungsten-bearintungsten-bearingg compoundcompound.. InIn majomajorr rhombohedrorhombohedronn r (1011(10Il)) incombinatioin combinationn witwithh thithiss neneww generatiogenerationn ooff KnischkKnischkaa synthetisyntheticc rubiesrubies,, ththee minominorr rhombohedrorhombohedronn z (olTI)(0111) werweree observedobserved crystalcrystalss witwithh columnarcolumnar habihabitt anandd a lengtlengthh ooff uupp ttoo 6 [Figure[Figure 5].. TheThe first-order hexagonahexagonall prisprismm m ccmm areare growgrownn [Figure[Figure 64]64].. ThesThesee crystalscrystals reacreachh a (1010)(1010) iiss subordinatsubordinatee iiff presenpresentt aatt all,all, anandd ooff smallsmall weighweightt aboveabove 100100 ct.ct. ThThee surfacesurface ooff thesthesee columnarcolumnar sizesize onlyonly.. appearinappearingg crystalcrystalss jiss formeformedd bbyy _ththee oscillatoryoscillatory NaturaNaturall amethystsamethysts aass wellwell aass heat-treateheat-treatedd ameth­ameth­ growngrown facesfaces n (2243)(2243) andand 11n (2243)(2243).. IInn facetedfaceted ystsysts frequentlfrequentlyy disclosedisclose growthgrowth planeplaness iinn ththee formform ooff samples,samples, besidebesidess feathersfeathers ofof residuaresiduall fluxflux_material, material, sharpsharp lamellarlamellar structures,structures, oftenoften connectedconnected witwithh a ththee oscillatoroscillatoryy occurrencoccurrencee ofof n (2243)(2243) anandd 11n (2243(2243)) iiss distincdistinctt colourcolour zoning.zoning. ThThee colourcolour zoningzoning parallelparallel ttoo distinctldistinctlyy recognizablerecognizable inin ththee immersioimmersionn micro­micro­ thethe positivpositivee anandd negativenegative rhombohedrrhombohedraa rrand and z isis scopescope [Figures[Figures 65-67]65-67].^ ThiThiss oscillationoscillation ofof ththee twotwo violet inin naturanaturall amethystamethyst andand yellowish-browyellowish-brownn inin pyramidapyramidall facefacess nnand and 11,w, formingforming anglesangles ofof 122.4°,122.4°, isis heat-treateheat-treatedd naturanaturall amethystamethyst (citrine).(citrine). GrowthGrowth easilyeasily observablobservablee iinn ththee vievieww perpendiculaperpendicularr ttoo thethe planesplanes,, whichwhich araree commonlycommonly paralleparallell toto ththee rhom­rhom- opticoptic axisaxis,, withwith a rotationrotation ooff ththee crystacrystall aboutabout thethe bohedrabohedrall faces,faces, forformm threethree characteristicharacteristicc angleangless ooff 360° verticalvertical axisaxis ofof ththee samplesample holderholder asas describeddescribed diagnosticdiagnostic .valuevalue. . StructuresStructures parallelparallel toto twtwoo positivepositive iinn ththee first parpartt ofof thisthis publicationpublication.. Consequently,Consequently, a rhombohedralrhombohedral facesfaces randr and rr'y {1011} 10 II} formform anan angleangle ofof significantsignificant andand diagnosticdiagnostic featurefeature isis nownow availableavailable 94.2°94.2° [Figure[Figure 68],68], growthgrowth planesplanes parallelparallel toto thethe forfor syntheticsynthetic rubierubiess ofof thatthat particulaparticularr generationgeneration ofof positivepositive rhombohedronrhombohedron r (WIl)(1011) andand thethe negativenegative KnischkaKnischka syntheticsynthetic rubies.rubies. SimilarSimilar oror identicalidentical rhombohedronrhombohedron z (OIIl)(OlTl) formform anan angleangle ofof 133.7°133.7° ifif growthgrowth structuresstructures werewere nevernever observedobserved inin naturalnatural bothboth facesfaces areare adjacentadjacent [Figures[Figures 69,70],69,70], andand anan angleangle stonesstones upup toto now.now. ofof 76.4°76.4° ifif theythey areare oppositeopposite toto eacheach otherother [Figure[Figure 71).71]. VI.VI. NaturalNatural amethystamethyst andand citrinecitrine BesidesBesides lamellarlamellar colourcolour zoningzoning parallelparallel toto thethe StructuralStructural propertiesproperties likelike growthgrowth planesplanes andand rhombohedralrhombohedral growthgrowth planes,planes, naturalnatural amethystamethyst andand twinningtwinning ofof bothboth naturalnatural asas wellwell asas syntheticsynthetic heat-treatedheat-treated naturalnatural amethystamethyst (citrine)(citrine) oftenoften revealreveal amethystamethyst andand citrinecitrine havehave alreadyalready beenbeen discusseddiscussed inin anotheranother kindkind ofof colourcolour zoningzoning inin thethe areasareas confmedconfined detaildetail inin earlierearlier issuesissues ofof thisthis journaljournal (Schmetzer,(Schmetzer, toto thethe positivepositive andand negativenegative rhombohedra.rhombohedra. TheThe 1986,1986, 1989;1989; LindLind & Schmetzer,Schmetzer, 1987).1987). InIn thesethese areasareas confinedconfined toto thethe positivepositive rhombohedronrhombohedron r earlierearlier articles,articles, however,however, onlyonly partpart ofof thethe nownow {lOll}{1011} inin naturalnatural amethystamethyst havehave a darkdark violet availableavailable methodsmethods usedused forfor thesethese investigationsinvestigations colour,colour, i heat-treatedheat-treated- naturalnatural amethystamethyst (citrine)(citrine) theythey werewere applied.applied. Therefore,Therefore, a summarysummary ofof thethe mostmost showshow anan intenseintense yellowyellow toto brownishbrownish colour,colour, whereaswhereas significantsignificant results,results, obtainedobtained byby thethe methodsmethods discus­discus­ inin thethejirea areass confinedconfined toto thethe negativenegative rhombohedronrhombohedron sedsed inin thethe firstfirst partpart ofof thisthis paper,paper, isis presented.presented. z {OlIl}{OlTl} thethe colourcolour isis a lighterlighter violetviolet oror a lighterlighter InIn allall roughrough samplessamples ofof naturalnatural amethystamethyst andand yellowish-brown,yellowish-brown, respectivelyrespectively [ef.[cf. FigureFigure 69]69).. 480 J. Gemm., 1991,22,8

^'- 4-^#vÄ^^;^^,.r;

Fig. 66. Growth structures in Knischka synthetic rubyj oscil­ Fig. 67. Growth structures in Knischka synthetic ruby_; oscil­ lating planes parallel to n (2243) and n (2243) form lating planes parallel to n (2243) and n (2243) form angles of 122.4°. View perpendicular to the oaxis, the angles of 122.4°. View perpendicular to the c-axis, the c-axis runs vertically. 25x. c-axis runs vertically. 40x.

Fig. 68. Angled growth structure in natural amethyst from Fig. 69. Angled growth structure in natural amethyst from Brazil; planes parallel to the positive rhombohedra r Uruguay; adjacent planes parallel to the positive and r' {1011} form an angle of 94.2°. View 38.2° rhombohedron r (101J.) and parallel to the negative inclined to the c-axis. 60x. rhombohedron z (0111) form an angle of 133.7°; growth sectors confined to the positive rhombohedron r [below] are dark violet, growth sectors confined to the negative rhombohedron z [above] are light violet in colour. View 38.2° inclined to the c-axis. 35x. J. Gemm., 1991,22,8 481

Fig. 70. Angled growth structure in natural citrine (heat- Fig. 71. Angled growth structure in natural citrine (heat- treated amethyst) from Brazil; adjacent planes parallel treated amethyst) from Brazil; opposite planes parallel to the positive rhombohedron r (1011) and parallel to to the positive rhombohedron r (1011) and parallel to the negative rhombohedron z (0111) form an angle of the negative rhombohedron z* (0111) form an angle of 133.7°. View 38.2° inclined to the c-axis. 40x. 76.4°. View perpendicular to the c-axis, the c-axis runs horizontally. Crossed polarizers. 26x. Polysynthetic twinning of the Brazil law, which is also a characteristic feature of natural amethyst and heat-treated natural amethyst (citrine) will not be discussed in this paper (cf. Schmetzer, 1986, 1989). However, it has to be mentioned, that in heat- treated natural amethyst an alteration of twinning may occur, which is connected with the develop­ ment of orientated brown striations, which are also useful as diagnostic criteria. In contrast to natural citrine obtained by heat treatment of natural amethyst, in natural untreated citrine the first-order hexagonal prism m (1010) is clearly developed (cf. Schmetzer, 1989). The crystal forms determined are the first-order hexagonal prism m {1010} and the positive rhombohedron r {10U} or, in other crystals, the forms m {1010}, r Fig. 72. Growth structures in hydrothermally-grown synthetic {1011}, and the negative rhombohedron z {0111}. citrine from USSR; residue of the seed orientated The angles formed by different crystal faces are parallel to the basal pinacoid c (0001) in the centre, identical with those of natural amethyst. In addi­ growth planes and colour zoning parallel to the bound­ ary seed/synthetic citrine. View perpendicular to the tion, an angle of 141.8°, formed by the two crystal c-axis, the c-axis runs horizontally. Crossed polarizers. faces m and r or by m and z may also occur. 30x. In natural untreated citrine, growth structures occur occasionally in broader distances than in natural amethyst. In cut samples, few single growth planes can be observed, which may form character­ istic angles as listed in Table 3. Twinning in natural citrine is occasionally present in form of inserted bodies or plates of quartz in an orientation different from the host crystal.

VII. Synthetic amethyst and citrine Synthetic amethyst is commercially grown by using seed plates cut parallel to the positive rhom­ bohedron r (lOTl) or parallel to the negative rhom­ bohedron z (OlTl). The main crystal growth habi­ tually is parallel to the seed plate, which means, Fig. 73. Growth structures in hydrothermally-grown synthetic parallel to one rhombohedral face. Parallel to this citrine from USA; growth lines parallel to the basal single dominant rhombohedral face, i.e. parallel to pinacoid c (0001). View perpendicular to the c-axis, the the seed plate, in different samples examined all c-axis runs vertically. Crossed polarizers. 32x. 484822 J.J. Gemm.,Gemm., 1991,22,81991, 22, 8

stagesstages ofof growthgrowth structuresstructures betweenbetween nono zoningzoning andand somesome furtherfurther developmentsdevelopments inin thethe recognitionrecognition ooff anan intenseintense lamellarlamellar zoningzoning asas observedobserved inin naturalnatural characteristiccharacteristic criteriacriteria whichwhich cancan bebe appliedapplied toto amethysamethystt areare observable.observable. However,However, itit hahass toto bebe problemsproblems ofof practicalpractical gemgem testingtesting andand gegemm identi­identi­ underlinedunderlined thatthat onlyonly inin thethe single dominantdominant growthgrowth fication. InIn general,general, ththee microscopicmicroscopic determinationdetermination directiodirectionn parallelparallel toto thethe seedseed platplatee distinctdistinct growthgrowth ofof growthgrowth structuresstructures andand twinningtwinning cancan revealreveal structuresstructures asas wellwell asas colourcolour zoningzoning areare observable.observable. criteria,criteria, whichwhich areare ofof comparablecomparable valuevalue forfor thethe NoNo characteristiccharacteristic anglesangles betweenbetween thisthis dominantdominant gemmologisgemmologistt asas thethe investigationinvestigation ofof chemicalchemical oror rhombohedralrhombohedral faceface andand otherother growthgrowth structures,structures, i.e.i.e. spectroscopicspectroscopic properties.properties. otherother rhombohedra,rhombohedra, werewere observedobserved soso farfar inin facetedfaceted samples.samples. ReferencesReferences InIn syntheticsynthetic amethyst,amethyst, a distinctdistinct typetype ofof twinningtwinning Coldham, T., T., 1985. 1985. Sapphires Sapphires from from Australia. Australia. Gems Gems & Gemology, & Gemolo­ maymay occuroccur occasionallyoccasionally (Lind(Lind & Schmetzer,Schmetzer, 1987).1987). 21, gy,130-46. 21, 130-46. InIn samplessamples ofof thisthis particularparticular type,type, triangulartriangular shapedshaped Galia,Galia, w.,W., 1987.1987. EineEine neueneue GenerationGeneration synthetischersynthetischer RubineRubine vonvon P.O.P.O. KnischkaKnischka unterunter VerwendungVerwendung natiirlichernatürlicher Niihrsubstanz.Nährsubstanz. twinnedtwinned areasareas areare incorporatedincorporated intointo ththee normallynormally Z. Dt. Gemmol. Ges., 36,19-31.36, 19-31. untwinneduntwinned hosthost crystal.crystal. TheseThese acute-angledacute-angled zoneszones Grubessi,Grubessi, 0.,O., Marcon,Marcon, R.,R., 1986.1986. A peculiarpeculiar inclusioninclusion inin a yellowyellow areare easilyeasily recognizablerecognizable underunder crossedcrossed polarizers.polarizers. corundumcorundum fromfrom Malawi.J.Malawi. J. Gemm., 20,163-5.20, 163-5. DifferentDifferent typestypes ofof commerciallycommercially producedproduced synth­synth­ Jobbins,Jobbins, E.A.,E.A., Berrange,Berrangé, J.P.,J.P., 1981.1981. TheThe PailinPailin RubRubyy andand SapphireSapphire Gemfield,Gemfield, Cambodia.J.Cambodia. J. Gemm., 17,555-67.17, 555-67. eticetic yellowyellow quartzquartz areare growngrown withwith seedseed platesplates Keller,Keller, P.C.P.c.,, 1982.1982. TheThe Chanthaburi-TraChanthaburi-Tratt GemGem Field,Field, Thailand.Thailand. orientatedorientated paralleparallell toto thethe basabasall pinacoidpinacoid c (0001).(0001). InIn Gems &&Gemology, Gemology, 18,18, 186-96.186-96. somesome ofof thethe samplessamples growthgrowth structuresstructures paralleparallell toto Kiefert,Kiefert, L.,L., Schmetzer,Schmetzer, K.,K., 1987.1987. BlueBlue andand yellowyellow sapphiresapphire fromfrom thethe seedseed plate,plate, paralleparallell toto thethe basalbasal pinacoidpinacoid c (0001),(0001), Kadun~Kaduna ProvinceProvince,, NigeriaNigeria.. J. Gemm., 20,20, 427427-42 -42.. Kiefert,Kiefert, C,L., Schmetzer,Schmetzer, K.,K., 1988.1988. Morpho.1ogyMorphology andand twinningtwinning inin inin connectionconnection withwith colourcolour zoningzoning werewere observableobservable ChathamChatham syntheticsynthetic blueblue sapphire.J.sapphire. J. Gemm., 21,21, 16-22.16-22. [Figures[Figures 72,72, 73]73] (Schmetzer,(Schmetzer, 1989).1989). ThisThis typetype ofof Kiefert, L., L., Schmetzer, Schmetzer, K., K., 1991a. 1991a. The The microscopic microscopic determination determina­ growthgrowth structurestructure isis neitherneither existentexistent inin naturalnatural tion ofof structuralstructural propertiesproperties forfor thethe characterizationcharacterization ofof amethystamethyst oror heat-treatedheat-treated naturalnatural amethystamethyst (citrine)(citrine) opticaloptical uniaxialuniaxial naturalnatural andand syntheticsynthetic gemstones.gemstones. PartPart 1:1: GeneralGeneral considerationsconsiderations andand descripti~ndescription ofof thethe methods.methods. J.J. nornor inin naturalnatural untreateduntreated citrine,citrine, becausebecause thethe basalbasal Gemm., 2222,, 344-54. 344-54. pinacoidpinacoid c (0001)(0001) doesdoes notnot appearappear asas a growthgrowth planeplane Kiefert, L., L., Schmetzer, Schmetzer, K., K., 1991b. 1991 The b. The microscopic microscopic determination determina­ inin naturalnatural quartz.quartz. AnAn additionaladditional characteristiccharacteristic fea­fea­ tion ofof structuralstructural propertiesproperties forfor ththee characterizationcharacterization ofof tureture ofof syntheticsynthetic citrinecitrine isis thethe lacklack ofof polysyntheticpolysynthetic opticaloptical uniaxialuniaxial naturalnatural andand syntheticsynthetic gemstones.gemstones. PartPart 2:2: ExamplesExamples forfor thethe applicabilityapplicability ofof structuralstructural featuresfeatures forfor thethe twinningtwinning asas itit isis commonlcommonlyy observedobserved inin naturalnatural distinction of of natural natural emerald emerald from fromflux-grown flux-grown and hydrothermally-grown and hyd­ amethystamethyst andand heat-treatedheat-treated naturalnatural amethysamethystt (cf.(cf. syntheticrothermally-grown emerald. J. Gemm., synthetic 22, 427-38. emerald.J. Gemm., 22, 427-38. sectionsection VI).VI). Knischka,Knischka, P.O.,P.O., 1989.1989. PersonalPersonal communications.communications. Knischka,Knischka, P.O.,P.O., Zirkl,Zirkl, E.J.,E.J., 1986.1986. Knischka-RubinedernulltenKnischka-Rubine der nullten bis drittendritten Generation Generation mit mit steigender steigender Zahl Zahlpräsenter priisenter Kristallflächen Kris­ VIII.VIII. ConclusionsConclusions tallfliichen alsals FunktionFunktion vonvon Wachstumsparametern.Wachstumsparametern. DGKKDGKK AsAs describeddescribed inin detaildetail inin thisthis thirdthird partpart ofof thethe Mitteilungsblatt, Nr. Nr. 43, 43, Juli Juli 1986, 1986,25-31. 25-31. paper,paper, thethe consequentconsequent determinationdetermination ofof growthgrowth Lind,Lind, T.,T., Schmetzer,Schmetzer, K.,K., 1987.1987. NeNeww investigationsinvestigations ofof syntheticsynthetic structuresstructures usingusing ththee easilyeasily availableavailable microscopicmicroscopic amethystsamethysts producedproduced inin Japan.Japan. J. Gemm., 20,20, 274-7274-7.. Rutland,Rutland, E.H.,E.H., 1969.1969. CorundumCorundum fromfrom Malawi.Malawi. J. Gemm., 1111,, methodsmethods introducedintroduced inin parpartt 1 ofof thethe publicationpublication 320-3.320-3. revealsreveals a greatgreat numbernumber ofof characteristicscharacteristics whichwhich cancan Schmetzer,Schmetzer, K.,K., 1986.1986. AnAn improvedimproved samplesample holderholder andand itsits useuse inin bebe usedused asas diagnosticdiagnostic criteriacriteria forfor ththee distinctiondistinction ooff thethe distinctiondistinction ofof naturalnatural andand syntheticsynthetic rubyruby asas wel.lwell asas naturalnatural andand syntheticsynthetic gemgem minerals.minerals. TheseThese addi­addi­ naturalnatural andand syntheticsynthetic amethyst.J.amethyst. J. Gemm., 20,20, 20-33.20-33. Schmetzer,Schmetzer, K.,K., 1987a.1987a. ZurZur DeutungDeutung derder FarbursacheFarbursache blauerblauer tionaltional diagnosticdiagnostic featuresfeatures cancan bbee extremelyextremely helpfulhelpful Saphire-eineSaphire - eine Diskussion.Diskussion. N.Jb. Miner. Mh., 1987,337-43.1987, 337-43. inin cases,cases, inin whichwhich nono unequivocallyunequivocally diagnosticdiagnostic Schmetzer,Schmetzer, K.,K., 1987b.1987b. ProductionProduction TechniquesTechniques ofof CommerciallyCommercially inclusionsinclusions araree availableavailable inin thethe facetedfaceted gemstonegemstone AvailableAvailable KnischkaKnischka SyntheticSynthetic RubiesRubies - AnAn AdditionalAdditional Note.Note. underunder investigation.investigation. TheThe methodsmethods describeddescribed cancan Aust. Gemmol., 16,16, 192-4.192-4. Schmetzer,Schmetzer, K.,K., 1989.1989. MethodsMethods forfor thethe distinctiondistinction ofof naturalnatural andand easilyeasily bebe mademade availableavailable forfor everyevery gemgem testingtesting syntheticsynthetic citrinecitrine andand prasiolite.J.prasiolite. J. Gemm., 21,21, 368-91.368-91. laboratorylaboratory andand thethe techniquestechniques ofof examinationexamination cancan Vichit,Vichit, P.,P., VudhichativanichVudhichativanich,, S.,S., Hansawek,Hansawek, R.,R., 1979.1979. TheThe bebe learnedlearned byby useuse ofof somesome characteristiccharacteristic samplessamples DistributionDistribution andand SomeSome CharacteristicsCharacteristics ofof Corundum­Corundum- withiwithinn a fewfew days.days. Hopefully,Hopefully, thethe applicationapplication ofof thethe BearingBearing BasaltsBasalts iinn Thailand.J.Thailand. J. Geol. Soc. Thailand, 3,3, M4-1M4-1 -M4-38.- M4-38. techniquestechniques describeddescribed willwill leadlead toto anan improvementimprovement ofof thethe methodsmethods byby otherother colleaguescolleagues asas wellwell asas toto {Manuscript[Manuscript receivedreceived 3 3 May May 1989.J1989.] J. Gemm., 1991,22,8 483 GEMSCALE 50 The Pocket Carat Scale fer Professional use

Weigh Precious Stones Precisely, Easily.... Any where

• 5" x 3" x 1 ". The only electronic carat scale • Automatic shut-off

you can fit in your pocket u ^Qm]k IAQM A mm im] • 50.50 carats x.01 carats. Precise weights for calibration weight is included a"your s,ones • Attached patented draftshield is a carrying • Easy one button operation case when closed • Full TARE capabilities up to 50.50 carats. • One year warranty on parts and labour • Carry anywhere. 9V battery operated. (excludin9 kn^ Made in USA Battery included.

I SPECIFICATIONS • Weighing Capacity 50.50 carats • Alkaline battery Life 300 operating hours • Resolution 01 carats • Heavy Duty Battery Life 200 operating hours • Tare Range 0... 50.50 carats • Dimensions (closed) 5.39" x 3.25" x 1.19" • Operating Temperature +60°... +100°F • Weight (including battery) 8.0 ounces

(+15°... +38°C) m Calibration weight 50.000±0025 carats • Storage Temperature -40°... +145°F (-40°... +60°C) £315.00 (Exclusive of VAT).

Gemmological Instruments Limited

• FIRST FLOOR, 27 GREVILLE STREET, (SAFFRON HILL ENTRANCE), LONDON EG N 8SU •

Tel: (071) 404 3334 Tel: (071) 404 8843 484 J. Gemm., 1991,22,8

The growth of rubies in south-east Kenya R.M. Key(1) and J.O. Ochieng(2)

(1) British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA. (2) Mines and Geological Department, PO Box 30009, Nairobi

Abstract of the Kurase Group (Pohl et ai, 1977, after Gem quality rubies from south-east Kenya, associated Saggerson, 1962). Psammitic gneiss is the dominant with small ultramafic intrusions, formed during a metasediment with marble and graphitic schist late Precambrian allochemical metamorphism under intercalations. Gem quality vanadiferous grossular upper amphibolite or granulite facies conditions. PT garnets ('tsavorite') occur in the graphitic schists; estimates for the metamorphism from two-feldspar these deposits have been described in a previous thermometry indicate temperatures of between 630 and 670°C at pressures in excess of 7 kbars. The red colour of paper (Key and Hill, 1989). The area around the rubies, as well as the green and blue body colour of Mangari comprises flat, poorly exposed, scrub- co-existing tourmalines and kyanites respectively, are all covered country. Bedrock is concealed beneath due to very high amounts of Cr2O3 in these minerals. layered superficial deposits of sand and black cotton Growth colour bands in the rubies reflect variations in soil above kunkar (secondary limestone). Prior to their crystal matrix Cr2O3 and TiO2 contents. Exsolved the ruby mining operations, the Mangari ultrama- rutile needles formed during cooling to cut across the fics were not exposed and are consequently not colour bands and may be related to decompression. shown on the original regional geological map of Walsh (1960). Similar ultramafics are best seen in Introduction northern Kenya in the Baragoi area (Figure 2). The The first discovery of corundum in south-east local geology of the Mangari area is described by Kenya, at Kinyiki, was announced in the Annual Walsh (1960) with Pohl et ai, (1977). Bridges (1982) Report for 1936 of the Geological Survey of Kenya. and Hughes (1990) providing descriptions explicit Small quantities of gem-quality sapphires were to the ruby mines. recovered from soils and gravels derived from corundum-bearing wall-rock to an ultramafic (du- On a regional scale the ruby deposits occur within nite) intrusive (Parkinson, 1947). It was in 1973 that the late Precambrian Mozambique Orogenic Belt the first rubies were found in south-east Kenya, in which underlies much of East Africa between the Mangari area, by two American geologists, John Ethiopia and Mozambique. The Mozambique Saul and Elliott Miller (Figure 1). The Mangari Orogenic Belt developed as a result of Neoprotero- ruby deposits are now known to be amongst the zoic collision between a western continental plate world's richest and Hughes (1990) notes that East (Tanzanian Craton) and an eastern 'Kibaran' plate. Africa in general has the potential to become the Shelf sediments and oceanic volcanics were laid future centre of world ruby mining. In order to down during an initial extensional phase and subse­ facilitate future exploration for new ruby deposits quently disrupted by major folding and associated the present study is an attempt to elucidate the ductile shearing and thrusting. This collision- physical conditions under which the rubies in the related deformation resulted in tectonic interfinger- Mangari area were formed. John Saul provided ing of different lithologies and lithostratigraphic samples of ruby and its rock matrix for optical and units. Regional metamorphism at amphibolite to chemical investigations. The mineral phases of the granulite facies, as well as crustal melt igneous ruby deposits were examined in thin sections and intrusion, accompanied deformation. The rubies electron microprobe analyses of polished thin sec­ formed during this event. tions provided the chemical compositions of the At the end of the Precambrian, meridional trans- main minerals. pressive shearing and folding was again accompa­ nied by regional metamorphism (greenschist to Geology amphibolite facies) with crustal melt igneous intru­ The Mangari ruby deposits occur at the contacts sion. of small ultramafic intrusions with metasediments Regional uplift throughout Cambrian times

© Copyright the Gemmological Association ISSN: 0022-1252 JJ.. Gemrn.Gemm.,, 1991,22, 8 484855

SUDASUDANN .,. ••

ETHIOPIA

SOMALIA

Fig.Fig. 1.1. TheThe geologicalgeological frameworkframework ofof KenyaKenya showingshowing thethe locationlocation ofof thethe studystudy area.area. accompaniedaccompanied orogenicorogenic cooling.cooling. RecentRecent reviewsreviews ofof 3.3. InIn aluminousaluminous metasedimentsmetasediments (not(not economicallyeconomically thethe MozambiqueMozambique OrogenicOrogenic BeltBelt areare givengiven byby CahenCahen importantimportant)).. elet ai.,ai, ((1984)1984),, ElEl GabyGaby andand GreilingGreiling (1988),(1988), Shackle­Shackle- 4.4. InIn marbles,marbles, associatedassociated withwith redred spinelspinel (not(not tonton (1986),(1986), andand KeyKey elet ai.,ai, (1989).(1989). economicallyeconomically important).important). AccordingAccording toto PohlPohl andand HorkelHorkel (1980)(1980) thethe corun­corun­ TheseThese authorsauthors notenote thatthat thethe MangariMangari rubiesrubies dumdum depositsdeposits ((iinn bedrock) ofof south-eastsouth-east KenyaKenya areare resultresult fromfrom complexcomplex desilicationdesilication processesprocesses betweenbetween ofof thethe followingfollowing fourfour types.types. smallsmall ultramaficsultramafics ((alterealteredd talctalc - enstatiteenstatite -- tremo­tremo- 1.1. DesilicatedDesilicated plumasiticplumasitic pegmatitespegmatites inin ultramaficultramafic litelite/anthopyllit/anthopyllitee -- chloritechlorite rocks)rocks) andand intrusiveintrusive bodies.bodies. pegmatitespegmatites oror paragneissesparagneisses (see(see alsoalso Hughes,Hughes, 19901990)). 2.2. DesilicationDesilication zoneszones atat thethe contactscontacts ofof thethe ultrama­ultrama- TheThe rubiesrubies areare associatedassociated withwith plagioclase,plagioclase, mica,mica, ficsfics andand metasedimentarymetasedimentary countrycountry rocks.rocks. tourmalinetourmaline andand kyanitekyanite inin thethe pegmatitespegmatites andand withwith 486 J. Gemm., 1991, 22, 8

Rift Valley volcanics Cr Chromite occurrence

p S 5 S— Cn Corundum occurrence Granite Fault /

Metasediments and metavolcanics

10 kilometres Ultramafic intrusion _J

Mafic intrusion with ultramafic pods

Fig. 2. Details of the geology of a well exposed area of north-central Kenya, near Baragoi, which illustrates the typical outcrop shape of ultramafic bodies in the Mozambique Orogenic Belt. J. Gemm., 1991,22,8 487

Plate 1. Colour zoned ruby with marginal white corundum rim. The diameter of the sample is about 2cm.

kyanite/sillimanite, tourmaline and mica aggregates Ruby -I- muscovite 4- phlogopite 4- plagioclase in the desilicated gneisses. All the mineral phases (andesine) 4- K-feldspar 4- tourmaline 4- kyanite 4- formed during the regional metamorphism which zircon (sample 8) controlled the desilication processes. Ruby 4- muscovite 4- plagioclase (oligoclase) + K-feldspar + zircon 4- xenotime (sample 9) Mineralogy Ruby 4- margarite 4- tourmaline (sample 11) The following ruby-bearing assemblages occur in Ruby 4- muscovite + pyrite 4- spinel (sample 12) the examined samples, Ruby forms idioblastic hexagonal prisms and Ruby 4- muscovite 4- plagioclase (oligoclase - elongate hexagonal spindles up to several cen­ andesine) 4- xenotime* (sample 4) timetres in diameter and mostly with a strong colour Ruby 4- phlogopite (sample 5) zoning mimicking the prism faces. This zoning is Ruby 4- muscovite 4- kyanite + plagioclase (sample best seen in sections cut parallel to the basal 5b) pinacoid and comprises white, pink and red sharp Ruby 4- phlogopite 4- plagioclase (andesine) (sam­ and diffuse bands (see Plate 1). Poly synthetic twins ple?) enhanced by long, white boehmite, AIO(OH), Ruby + margarite - paragonite 4- plagioclase needles (Hughes, 1990) cut across the colour zoning (bytownite-labradorite) 4- tourmaline 4- graphite (see Plate 2). Rutile needles orientated parallel to (sample 8) the faces of the hexagonal prism to intersect at 120° ^Identified on the electon microprobe are ubiquitous. The needles also cut the colour 488 J. Gemm, 1991,22,8

Plate 2. Twin planes in ruby cutting across the colour zoning. White boehmite needles may be aligned in the twins (Sample 6). Field of view about 0.8mm by 1mm.

Plate 3. Oriented rutile needles and equant mica inclusions in ruby. Note that the rutile needles cut across the colour banding (Sample 3). Field of view about 3mm by 4mm.

Plate 4. Close up of Plate 3. Field of view about 0.8mm by 1mm. J. Gemm, 1991,22,8 489

Plate 8. Mesoperthite with white albite spindles in K-feldspar. Sample 9. Field of view about 0.8mm by 1mm.

banding (see Plates 3 and 4). Less common inclu­ which indicates that the cooling history was not sions are small, colourless to pale green chrome- isobaric. Pressure release on cooling may explain muscovite plates (see Plates 3 and 4). One sample the pronounced orientation of exsolved rutile in the comprised a red, translucent ruby with massive rubies, caused by slight expansions of the ruby rutile grains embedded in its centre (Plate 5 - see lattice. cover picture). The rutile needles formed after the colour banding and are regarded as exsolution Chemistry features produced during cooling of the rubies (see The various mineral phases were chemically also Hughes, 1990). Their distribution is influenced analysed on the Edinburgh University Cameca by the distribution of Ti02 in individual grains and Camebax electron probe micro-analyser operating a close examination of Plates 3 and 4 shows that at an accelerating potential of 20 kv, with a probe there is a strong concentration in the darker bands current, as measured in a Faraday Cup, of 20 of rutile needles aligned parallel to the banding. nanoamps (see Key and Hill, 1989). Standards used The microprobe data confirm that the dark bands in the calibration were as follows: wollàstonite for are enriched in crystal matrix Ti02 relative to the silicon and calcium, jadeite for sodium, corundum lighter bands (see below). for aluminium, periclase for magnesium, rutile for Ruby appears to be in equilibrium with the other titanium, orthoclase for potassium, and the artificial phases although marginal margarite plates may be compound MgF2 for fluorine. Other elements replacive (see also Harding and Scarratt, 1986). (vanadium, chromium, manganese and iron) were Plagioclase is more abundant than K-feldspar; both calibrated against pure metals. Matrix corrections minerals form an equigranular groundmass with were carried out using a ZAF process similar to that accessory zircon and xenotime (Plate 8). The pla­ described by Sweatman and Long (1969). The gioclase grains are commonly polysynthetically analyses occur at single points within individual twinned but the K-feldspar is untwinned with rare grains and the point fluorescence during analysis mesoperthitic textures (Plate 8). Tourmaline and provides instant confirmation of the nature of kyanite form poikilitic grains in the presence of certain analysed minerals. Rubies have a red feldspar. They have strong green (tourmaline) and fluorescence under the probe beam; chrome-rich blue (kyanite) body colours (Plates 6 and 7). (mean value of 0.424% Cr2 03) kyanite also has a red Graphite forms isolated typically ragged blades fluorescence which changes to pale blue in the (Plate 9). presence of significant titanium (0.127-0.152 % The mineral phases are generally unaltered as can Ti02). be seen in the various plates. There is local marginal alteration of ruby to margarite and minor sericite Ruby analyses replacement of the feldspar. The absence of fluids in Tables 1 and 2 summarize the results of the ruby the rocks following high grade metamorphism may analyses. It is apparent from these tables that the have prevented major retrogression during cooling. main chromophore is Cr203. In the unzoned rubies Sillimanite has been recorded after kyanite in the mean Cr203 content varies from 0.391 to south-east Kenya (Pohl and Niedermayr, 1978) 0.963% with the highest values in the best quality 490 J. Gemm., 1991,22,8

Plate 6. Green tourmaline and ruby cluster. Size of specimen about 3cm.

Plate 7. Blue kyanite and ruby. Size of specimen about 3cm. J. Gemm.3 1991,22,8 491

Table 1: Mean ruby analyses for unzoned rubies

Sample Sample Sample Sample 7 8b 11 8 Mangari* Umba* Morogoro* AlA 99.546 99.336 99.803 99.647

Cr203 0.963 0.920 0.447 0.391 1.10-1.80 0.01-0.10 0.060-0.090

Ti02 0.029 0.030 0.016 0.024 0.006-0.020 v2o5 0.039 0.027 0.009 0.027 0.000-0.003 0.002-0.01 0.004 FeO 0.017 0.008 0.013 0.010 0.060-0.50 0.10-0.25 0.010-0.020 Total 100.594 100.321 100.288 100.099 n 5 2 5 4 Values In weight % n - No. ofanalyses * From Hughes (1990), Umba and Morogoro are in Tanzania (reddest) stones. The chrome values are slightly tourmalines reported to occur in south-east Kenya lower than those reported by Hughes (1990) for are unlikely to come from Mangari. This is sup­ Mangari rubies but are still higher than rubies from ported by field evidence (J. Saul, pers. comm.). adjacent parts of Tanzania. The ultramafic intru­ Similarly the blue body colour of the kyanite blades sions are thought to be the original source of the (Plate 7) is due to Cr203 (mean value 0.424%). The chromium as these rocks have high Cr203 and chrome content of the kyanites is amongst the locally, in Kenya, host podiform chromite (Key, highest ever reported. Altherr and others (1982) 1987). Iron contents are very low which is reflected record values of 0.139% Cr203 for Tanzanian by the lack of brown tints to the Mangari rubies - kyanite which they regard as exceptionally high. one of the reasons that they are so prized as Table 4 shows two ICP (inductively coupled plasma) gemstones. Vanadium contents are also very low in spectrometry analyses of tourmalines from Man­ the rubies and all the other mineral phases. gari. These analyses are similar to the microprobe The internal colour banding of dense or partly analyses and they also provide data on the boron translucent ruby grains is reflected by variable contents of the tourmaline. Cr203 and Ti02 contents (Figure 3 and Table 2). The most common plagioclase phases have com­ The darker (redder) bands have higher Cr203 positions in the oligoclase-andesine range. Albite values relative to adjacent paler bands and the occurs as late overgrowths or as lamellae within overall mean Cr203 value for the dark bands is mesoperthites (Plate 8). The most calcic plagioc- significantly higher than the corresponding figure lases are associated with margarite and tourmaline for the light bands (0.571% compared with 0.400%). and the host rock must consequently have been The same is true for the distribution of Ti02 relatively calcic. Barium was detected in the K- (0.286% mean value for dark bands and 0.168% feldspar grains but was not quantitatively analysed. mean value for light bands). The colour banding is regarded as a primary growth feature; diffusion of Metamorphism Cr203 and Ti02 in the ruby crystal matrix. As Previous work in south-east Kenya has shown shown earlier, the Ti02 at least in part, was exsolved that the grade of the regional metamorphism within during cooling as orientated needles. the Mozambique Oogenic Belt attained upper amphibolite or granulite facies conditions (see Pohl Other minerals and Niedermayr, 1978; Key and Hill, 1989). The Table 3 presents the mean chemical analyses of peak temperature of the progressive metamorphism the main mineral phases associated with ruby. All in this area has been established as greater than the micas have significant Cr203 values. In particu­ 550°C and possible over 750°C. Thus, Arneth and lar the muscovites have mean Cr203 values of others (1985) deduced that the metamorphism took 0.447% with the bright green fuchsitic micas having place at temperatures of between 550°C and 650°C mean Cr203 values of 3.130%, and the highest based on carbon isotope studies of the graphitic individual analysis of 5.925% Cr203. For reference, metasediments. Key and Hill (1989) concluded that Deer and others (1970) record maximum values of the peak temperature of metamorphism was at least about 6% Cr203 for fuchsite. The fuchsite inclu­ 750°C based on mineral assemblages in the grossu- sions in the Mangari rubies have the highest Cr203 lar deposits of Mgama Ridge. Similar temperatures values. were established by Sarbas and others (1984) who, The green body colour of the tourmaline (Plate 6) from their studies of the grossular garnet-bearing assemblages, concluded that peak temperatures is due to Cr203 (mean value 0.478%) and not V205 (mean value 0.061%). Therefore the vanadiferous exceeded 650°C. Pressures during metamorphism 492 J. Gemm., 1991,22,8

Table 2: Mean analyses (in weight %) of a single zoned ruby from Mangari (see Figure 3) 2A Light toned bands

1 2 3 4 5 6 7 8 9

Al2o3 99.540 99.634 99.735 99.453 99.718 99.985 99.870 99.849 99.741

Cr203 0.427 0.414 0.372 0.385 0.362 0.343 0.336 0.302 0.400

TiOz 0.041 0.065 0.064 0.146 0.057 0.047 0.046 0.054 0.168 v2o5 0.003 0.020 0.012 0.000 0.022 0.009 0.022 0.009 0.017 FeO 0.000 0.011 0.011 0.010 0.005 0.019 0.020 0.012 0.011 Total 100.011 100.144 100.194 99.994 100.164 100.403 100.294 100.226 100.337 n 3 3 13 2 4 7 3 2 7 n-No. of analyses 9: mean analyses for 7 bands in sample 9

(Table 2 cont'd: Mean ruby analyses for dark toned bands (see Figure 3) 2B Dark toned bands

10 11 12 13 14 15 16 17 18 19 20

A1203 99.311 99.181 99.625 99.727 99.336 99.683 99.409 99.646 99.777 99.502 99.351

Cr203 0.619 0.523 0.505 0.489 0.475 0.415 0.377 0.367 0.330 0.294 0.571

Ti02 0.126 0.528 0.064 0.122 0.140 0.374 0.318 0.205 0.285 0.478 0.286 0.043 0.010 0.016 v2o5 0.017 0.034 0.010 0.044 0.030 0.011 0.012 0.024 FeO 0.006 0.008 0.011 0.002 0.006 0.012 0.006 0.015 0.020 0.012 0.018 Total 100.079 100.274 100.248 100.350 99.967 100.528 100.126 100.263 100.423 100.298 100.250 n 3 5 3 3 2 3 4 9 2 4 5

10: mean analyses for 7 bands in sample 9

Table 3: Mean mineral analyses (excluding ruby)

1 2 3 4 5 6 7 8 9 10 11 12 13

Na20 0.487 2.404 0.234 4.318 0.563 9.951 9.412 7.628 4.435 2.639 1.059 1.655 0.014

Si02 45.617 35.067 40.921 41.070 44.863 67.429 63.069 59.424 52.333 48.226 63.475 37.462 36.917

K20 10.518 0.209 8.692 0.460 9.940 0.684 0.181 0.159 0.051 0.033 14.173 0.042 0.009

Cr203 0.447 0.133 0.371 0.00 3.130 0.016 0.016 0.020 0.018 0.015 0.001 0.478 0.424 F 0.046 0.016 0.556 0.039 0.219 0.040 0.00 0.093 0.055 0.00 0.037 0.166 0.038 AI2O3 36.271 45.754 22.609 43.971 32.239 21.437 22.836 25.371 29.816 32.216 18.256 33.688 62.672 CaO 0.008 9.251 0.036 2.331 0.007 0.395 4.168 7.071 11.219 14.279 0.008 1.771 0.006 v2o5 0.262 0.020 0.060 0.00 0.487 0.00 0.029 0.015 0.00 0.014 0.001 0.061 0.017 MgO 0.560 0.075 17.821 0.171 1.662 0.225 0.010 0.018 0.002 0.014 0.009 10.339 0.044

Ti02 0.156 0.023 0.590 0.018 0.331 0.008 0.016 0.012 0.018 0.008 0.005 0.313 0.078 MnO 0.015 0.006 0.037 0.00 0.031 0.009 0.010 0.018 0.004 0.013 0.009 0.016 0.003 FeO 0.162 0.024 0.040 0.019 0.034 0.014 0.003 0.014 0.019 0.009 0.007 0.042 0.037 Total 94.549 92.982 91.969 92.397 94.506 100.206 99.793 99.732 97.969 97.466 97.574 86.032 100.253 n 9 6 9 2 7 2 3 6 1 3 3 11 7 Values in weight % n = No. of analyses 1. Muscovite 8. Andesine 2. Margarite 9. Labradorite 3. Phlogopite 10. Bytownite 4. Paragonite 11. K-feldspar 5. Fuchsite 12. Tourmaline 6. Albite 13. Kyanite 7. Oligoclase (A complete list of analyses is available from the authors) J. Gemm., 1991, 22, 8 493

*/*-£

El , t?*J .Si

^SHI^

Fig. 3. The analysed ruby with the locations of the analysed pale and dark bands shown in Table 2. 494944 J.J. Gemrn.,Gemm., 1991,22,81991,22,8

TableTable 4:4: TwoTwo ICICPP analyseanalysess ofof tourmalinetourmaline grainsgrains assemblagesassemblages.. AltherrAltherr anandd othersothers (1982)(1982) concludedconcluded fromfrom MangariMangari thathatt corundumcorundum inin ththee MorogorMorogoroo areareaa ooff TanzaniaTanzania formedformed inin a metamorphismmetamorphism withwith temperaturetemperaturess ooff Tourmaline 3 3 Tourmaline 10 aboutabout 695°C695°C aatt 7.7.77 kbarkbarss pressurpressuree (assuming(assuming anan SiOzSi02 39.3039.30 38.1338.13 activitactivityy ofof HzOH20 ofof 1).1). ThiThiss wawass basedbased onon thethe A}z03A1203 29.829.866 30.0430.04 assemblages,assemblages, albitialbiticc plagioclasplagioclasee +4- muscovitemuscovite + TiOTi02z 0.30.355 0.300.30 phlogopitephlogopite 4+- corunducorundumm andand albiticalbitic plagioclaseplagioclase + Fe203Fe203 0.310.31 0.40.422 kyanitekyanite oror sillimanitesillimanite + phlogopite.phlogopite. TheseThese assemb­assemb­ MgOMgO 9.959.95 10.8210.82 lagelagess occuroccur aatt MangariMangari.. HoweverHowever,, nono accountaccount ooff thethe CaCaOO 2.42.400 1.571.57 effecteffect ofof ththee presencepresence ofof CaCaOO iinn ththee mineraminerall phasesphases K 2200 0.350.35 0.10.133 waswas taketakenn bbyy AltherAltherrr andand hishis co-workersco-workers.. ThThee veryvery NaNazO20 1.821.82 1.661.66 detaileddetailed studystudy byby CartwrighCartwrightt anandd BarnicoatBarnicoat (1986)(1986) MnMnOO 0.00.022 0.00.022 oonn corundum-bearincorundum-bearingg restiterestitess fromfrom ScotlandScotland doesdoes PzOsP205 0.00.044 0.00.044 discussdiscuss ththee effecteffect ooff CaO.CaO. TheTheyy notenote thathatt thethe Bz2003 9.19.177 9.739.73 assemblageassemblage,, corunducorundumm + K-feldsparK-feldspar + whitewhite micamica CCrr 840840 ppm 10301030 ppm + plagioclaseplagioclase + kyanitekyanite + liquid,liquid, indicatesindicates temper­temper­ ZZnn 282800 ppm 7755 ppm atureature ooff aroundaround 800°C800°C withwith pressurepressuress ofof abouaboutt 1122 kbarskbars.. TheThe PTPT conditionsconditions aatt MangarMangarii cannocannott bebe exactlyexactly specifiedspecified beausebeause ofof thethe non-stoichiometricnon-stoichiometric areare nonott soso wellwell constraineconstrainedd andand havhavee beebeenn estimatedestimated compositionscompositions ofof thethe mineralmineral phasephasess aatt MangariMangari andand atat greategreaterr thathann 5 kbarkbarss withwith nnoo uppeupperr limilimitt yeyett becausbecause,e ooff ththee unknownunknown compositioncomposition ooff ththee fluidfluid established.established. GneissesGneisses bearinbearingg twtwoo pyroxenespyroxenes areare phasesphases.. However,However, itit cancan bebe concludeconcludedd thatthat thethe recordedrecorded bbyy WalshWalsh (1960)(1960) fromfrom thethe areaarea southsouth oofthef the presentpresent studystudy hashas confirmeconfirmedd thathatt thethe MangariMangari TaitTaitaa Hills,Hills, ttoo supportsupport ththee conclusionconclusion thatthat thethe rubierubiess formedformed duringduring a metamorphismmetamorphism whichwhich metamorphismmetamorphism attaineattainedd granulitegranulite faciefaciess conditions.conditions. reachereachedd granulitegranulite faciesfacies conditions,conditions, defineddefined aass IInn ththee presentpresent studystudy iitt iiss possiblpossiblee ttoo estimatestimatee thethe temperaturestemperatures iinn excessexcess ofof aboutabout 650°C650°C irrespectiveirrespective PTPT conditionconditionss ooff thethe metamorphismmetamorphism durinduringg whichwhich ooff pressure,pressure, seesee MiyashiroMiyashiro (1961)(1961) anandd ZwarZwartt (1967)(1967).. ruby-formedruby. formed,, bbyy twtwoo methodsmethods.. A direcdirectt methodmethod ItIt iiss relevanrelevantt ttoo notnotee thatthat MaesschalcMaesschalckk andand OenOen useusess thethe compositionscompositions ooff co-existinco-existingg plagioclasplagioclasee andand (1989)(1989) showshow thathatt SriSri LankaLankann rubiesrubies,, founfoundd inin K-feldspar.K-feldspar. ThusThus HaseltoHaseltonn anandd othersothers (1983)(1983) propro­­ similarsimilar rockrockss toto thethe KenyaKenyann rubies,rubies, formedformed underunder videvide ththee followingfollowing formula:formula: ververyy similarsimilar conditionconditionss toto thosethose specifiedspecified iinn thethe lastlast

T _ (Xl5:.'i(18810(Xêf)2(18810 + 1703017030X*~X\l ++ 0.364P)0.364P) - (Xx)'i(28230(X£j2(28230 - 39520XXh)39520X&)

2 2 K - 10.310.3 (Xl5:.'i(Xèf) + 8.31431n8.31431n { (XXhi(2A;(*A!0 (2JX& XXh)) }\ v. XAbAb J

WherWheree T k = TemperatureTemperature (°C(0C)) twtwoo paragraphsparagraphs.. TheyThey recorrecordd thathatt ththee rubierubiess formedformed P = PressurePressure (bars)(bars) duringduring a metamorphismetamorphismm withwith a temperaturtemperaturee ooff X = VariouVariouss molmolee fractionsfractions iinn thethe ternaryternary aboutabout 630°C630°C anandd pressurepressuress ooff abouaboutt 5.55.5 kbars.kbars. system,system, orthoclaseorthoclase (Or)-albite(Or)-albite (Ab)-Anor­(Ab)-Anor- RubiesRubies inin TanzaniaTanzania araree alsoalso foundfound iinn areasareas ofof thethe thitethite (An).(An). AAFF anandd PIPI referrefer toto alkalalkalii feldsparfeldspar MozambiqueMozambique OrogenicOrogenic BelBeltt whicwhichh preservpreservee granu­granu­ andand plagioclasplagioclasee respectively.respectively. litelite faciefaciess mineraminerall assemblagesassemblages (Malisa andand Muhon­Muhon- ThiThiss equatioequationn iiss preferrepreferredd ttoo otheotherr two-feldspartwo-feldspar gogo,, 1990).1990). thermometersthermometers becausbecausee iitt takestakes iinn ttoo accountaccount thethe anorthitanorthitee contencontentt ofof botbothh plagioclasplagioclasee anandd K­K- feldspafeldsparr whicwhichh isis significantsignificant inin thethe MangariMangari feld­feld­ spars. Using the feldspar analyses summarised in PlatPlatee 99.. EquigranulaEquigranularr plagioclaseplagioclase grainsgrains withwith raggeraggedd graphitegraphite spars. Using the feldspar analyses summarised in flakes (centre(centre ooff plateplate)) anandd tourmalintourmalinee intergrowthsintergrowths TableTable 3 inin ththee aboveabove formulaformula provideprovidess temperaturestemperatures (yellow)(yellow).. SampleSample 8.8. FieldField ooff vievieww abouaboutt 3mm3mm by4mm.by 4mm. ofof betweenbetween 630°C630°C andand 670°C670°C irrespectiveirrespective ofof press­press­ ureure.. ThThee presencepresence ooff kyanitkyanitee asas thethe AlAlzSiO2Si05s poly­poly­ PlatPlatee 10.10. TwoTwo rubrubyy grainsgrains (on(onee stronglystrongly twinnedtwinned)) withwith idioblasidioblas­- morph indicates that pressures must have exceeded tictic tourmalintourmalinee anandd interstitiainterstitiall margaritemargarite.. SampleSample 1111.. morph indicates that pressures must have exceeded FieldField ooff viewview abouaboutt 3mm3mm bbyy 4mm.4mm. 7 kbarskbars inin thisthis temperaturetemperature rangerange (Holdaway,(Holdaway, 1971).1971). TheseThese PPTT conditionconditionss agreeagree withwith previousprevious worworkk asas PlatPlatee 11.11. SeveralSeveral rubrubyy grainsgrains withwith interstitialinterstitial tourmalinetourmaline.. SamSam­­ listedlisted earlier.earlier. pleple 11.11. FielFieldd ofof viewview aboutabout 3m3mmm bbyy 4mm.4mm. AAnn indirecindirectt approacapproachh ttoo ascertaininascertainingg ththee PTPT PlatPlatee 12.12. IntergrowtIntergrowthh ooff muscovitmuscovitee withwith rubyruby;; plagioclasplagioclasee grainsgrains conditionconditionss ooff ththee metamorphismmetamorphism iiss providedprovided byby clustereclusteredd iinn lowerlower lefleftt handhand cornercorner ooff thethe plateplate.. SampleSample experimentaexperimentall datdataa oonn ththee stabilitystability ooff thethe mineralmineral 99.. FieldField ooff vievieww abouaboutt 3mm3mm byby 4mm.4mm. J.J. Gemm.,Gemm., 1991,22,81991,22,8 495495

Plate 9 Plate 10

Plate II Plate 12 496496 J.J. Gemm.,Gemm., 1991,22,81991,22,8

ConclusionsConclusions Deer,Deer, W.A.,W.A., Howie,Howie, RA.,R.A., Zussman,Zussman, J.,J., 1970.1970. An introductionintroduction toto 1.1. TheThe MangariMangari rubiesrubies formedformed duringduring regionalregional thethe rock formingforming minerals.minerals. 6th6th edition.edition. LongmanLongman GroupGroup Ltd.,Ltd., London.London. 528pp.528pp. metamorphismmetamorphism underunder upperupper amphiboliteamphibolite toto granu­granu- EIEl Gaby,Gaby, S.,S., Greiling,Greiling, R.,R., 1988.1988. The Pan-African belt of northeast litelite faciesfades conditions:conditions: minimumminimum temperaturestemperatures ofof Africa and adjacent areas: tectonictectonic evolution and economiceconomIc betweenbetween aboutabout 630630 andand 670°C670°C andand pressurespressures inin aspects of a latelate Proterozoic orogen. EF. ViewegVieweg andand Sohn,Sohn, excessexcess of7of 7 kbars.kbars. Wiesbaden,Wiesbaden, 369pp.369pp. Harding,Harding, R.R,R.R., Scarratt,Scarratt, K.,K., 1986.1986. A descriptiondescription ofof rubyruby fromfrom 2.2. TheThe pinkpink andand redred bodybody colourscolours ofof thethe rubiesrubies areare NNepal epaJ.. Journal of Gemmology, 20,20, 3-10.3-10. duedue toto highhigh valuesvalues ofof CrZ03Cr203 inin thethe rubyruby matrixmatrix andand Haselton,Haselton, H.T,H.T., Hovis,Hovis, G.L.,G.L., Hemingway,Hemingway, B.S.,B.S., Robie,Robie, R.A.,R.A., lowlow valuesvalues ofof FeO.FeO. TitaniumTitanium isis presentpresent inin signifi­signifi­ 1983.1983. CalorimetricCalorimetric investigationinvestigation ofof thethe excessexcess entropyentropy ofof cantcant amountsamounts whichwhich isis partlypartly reflectedreflected byby thethe mixingmixing inin analbite-sandineanalbite-sandine solidsolid solutions:solutions: lacklack ofof evidenceevidence forfor Na,Na, K short-rangeshort-range orderorder andand implicationsimplications forfor two­two- ubiquitousubiquitous presencepresence ofof exsolvedexsolved rutilerutile needles.needles. feldsparfeldspar thermometry.thermometry. American Mineralogist, 68,68, 398-413.398-413. VanadiumVanadium isis onlyonly presentpresent inin tracetrace amounts.amounts. Holdaway, M.J.,M.J., 1971. 1971. Stability Stability of andalusiteofandalusite and andthe aluminosilicate the alumino­ 3.3. TheThe strongstrong colourcolour bandingbanding isis duedue toto variationsvariations inin silicate phasesphases diagram.diagram. American Journal of Science, 271271,, thethe chromiumchromium andand titaniumtitanium contentscontents ofof thethe rubies.rubies. 97-131. Hughes,Hughes, RW.,R.W., 1990.1990. Corundum. Butterworth-HeinemannButterworth-Heinemann 4.4. ChromiumChromium isis alsoalso thethe chromophorechromophore inin greengreen 336pp.336pp. tourmalinetourmaline andand inin blueblue kyanitekyanite associatedassociated withwith thethe Key,Key, RM.,R.M., 1987.1987. GeologyGeology ofof thethe MaralalMaralal area.area. Report, Mines and rubies.rubies. TheThe ultramaficultramafic rocksrocks associatedassociated withwith thethe Geological Department, Kenya, 105,93pp.105, 93pp. rubiesrubies providedprovided thethe chromium.chromium. Key,Key, R.M.,R.M., Hill,Hill, P.G.,P.G., 1989.1989. FurtherFurther evidenceevidence forthefor the controlscontrols onon thethe growthgrowth ofof vanadiumvanadium grossulargrossular garnetsgarnets inin Kenya.Kenya. JournalJournal of Gemmology, 31,412-22.31, 412-22. FutureFuture workwork Key,Key, R.M.,R.M., Charlsley,Charlsley, T.J.,T.J., Hackman,Hackman, B.D.,B.D., Wilkinson,Wilkinson, A.E,A.F., ManyMany ultramafiultramaficc intrusionsintrusions inin south-eastsouth-east KenyaKenya Rundle, C.G., CG., 1989. 1989. Superimposed Superimposed Upper Upper Proterozoic Proterozoic collision-controlled colli­ dodo notnot appearappear toto havehave marginalmarginal rubyruby deposits.deposits. ThereThere sion-controlled orogeniesorogenies inin thethe MozambiqueMozambique OrogenicOrogenic BeltBelt of Kenya. PrecambrianPrecambrian Research, Research, 44 44,, 197-225. 197-225. is an obvious need toto compare the composition of is an obvious need compare the composition of Maesschalck, A.A., A.A., Oen, Oen, I.S., I.S., 1989. 1989: Fluid Fluid and mineral and mineral inclusions inclu­ thethe barrenbarren ultramaficsultramafics withwith ruby-relatedruby-related ultrama­ultrama- in corundumsions in corundum from gem gravelsfrom gem in Sri gravels Lanka. in Mineralogical Sri Lanka. Mineralo­ fics inin orderorder toto seesee ifif therethere areare chemicalchemical differencesdifferences Magazine,gical Magazine, 53, 539-45. 53, 539-45. betweebetweenn thethe twtwoo sites.sites. ThThee chemistrychemistry ofof thethe ultra­ultra­ Malisa,Malisa, E.,E., MuhongoMuhongo,, S.,S., 1990.1990. TectonicTectonic settingsetting ofof gemstonegemstone mineralisation in the Proterozoic metamorphic terrane of the mafics must significantly affect the desilication mineralisation in the Proterozoic metamorphic terrane of the mafics must significantly affect the desilication MozambiquMozambiquee BeltBelt inin Tanzania.Tanzania. Precambrian Research, 46,46, processprocess whichwhich formedformed ruby.ruby. 167-76.167-76. Miyashiro,Miyashiro, A.,A., 1961961 I.. EvolutionEvolution ofof metamorphicmetamorphic belts.belts. Journal Journal ofof AcknowledgementsAcknowledgements Petrology, 2,2, 277-31277-311 I.. Parkinson,Parkinson, J.,J., 1947.1947. OutlinesOutlines ofof thethe geologygeology ofof thethe MtitoMtito ThisThis paperpaper isis publishedpublished withwith ththee permissionpermission ofof Andei-Andei-TsavTsavoo area,area, KenyaKenya Colony.Colony. Geological Survey of thethe DirectorDirector ofof BGSBGS (NERC),(NERC), andand thethe Commission­Commission­ Kenya, ReportReport13. 13. eerr ooff MineMiness and-Geologyand. Geology,, NairobiNairobi.. ThThee authorauthorss araree PohlPohl,, W.w.,, HorkelHorkel,, A.A.,, 1980.1980. NoteNotess oonn ththee geologgeologyy anandd mineralmineral resources of the Mtito Andei-Taita area (southern Kenya). indebteindebtedd ttoo DDrr PetePeterr HilHilll ooff EdinburgEdinburghh UniversityUniversity resources of the Mtito Andei-Taita area (southern Kenya). for his help with the probe analyses. Dr John Saul MittMitt.. osterr. geol.geol. Ges., Ges., 73,73 , 135-52.135-52 . for his help with the probe analyses. Dr John Saul PohlPohl,, W.w.,, NiedermayrNiedermayr,, G.G.,, 1978.1978. GeologGeologyy ooff ththee MwatateMwatate nonott onlonlyy provideprovidedd alalll ththee rubrubyy samplessamples bubutt wawass a quadranglquadranglee (shee(sheett 195/2)195/2) anandd ththee vanadium-grossularitevanadium-grossularite sourcsourcee ooff mucmuchh usefuusefull informationinformation.. HHee iiss sincerelysincerely depositdepositss ooff ththee areaarea.. Report 11, Kenya - Austria Mineral thankethankedd foforr hihiss positivpositivee contributioncontributionss ttoo thithiss projectproject Exploration Project. 89pp89pp.. which was partly funded by the British Council. PohlPohl,, W.w.,, NiedermayrNiedermayr,, G.G.,, HorkelHorkel,, A.A.,, 1977.1977. GeologGeologyy ooff thethe which was partly funded by the British Council. MangarMangarii rubrubyy minesmines.. Report 9, Kenya - Austria Mineral Exploration Project. 70pp.70pp. ReferenceReferencess Saggerson,Saggerson, E.P.E.P.,, 1962.1962. GeologGeologyy ooff ththee Kasigau-KurasKasigau-Kurasee area.area. AltherrAltherr,, R.R.,, OkruchOkruch,, M.M.,, BankBank,, H.H.,, 19821982.. CorunduCorundumm andand Geological Survey of Kenya, ReportReportS/. 51. Sarbas, B., Goerg, Amstutz, G.C, Schmetzer, K., Bank, H., kyanite-bearing anatexites anatexites from from the Precambrianthe Precambrian of Tanzania. of Tanza­ Sarbas, B., Goerg, W.w.,, Amstutz, G.C., Schmetzer, K., Bank, H., 1984. Zur genese ostafrikanischer Grossularvorkommen. Z. Lithos,nia. 15Lithos,, 191-7. 15, 191-7. 1984. Zur genese ostafrikanischer Grossularvorkommen. Z. ArnethArneth,, J.D.J.D.,, SchidlowskiSchidlowski,, M.M.,, SarbasSarbas,, B.B.,, GoergGoerg,, V.V.,, Amstutz,Amstutz, Dt Gemmol.Gemmo!. Ges., 3333,, 48-6248-62.. Shackleton, R.M., 1986. Precambrian collision tectonics in G.C.G.C,, 19851985.. GraphitGraphitee contencontentt anandd isotopiisotopicc fractionationfractionation Shackleton, R.M., 1986. Precambrian collision tectonics in Africa. In: M.P. Coward and AC Ries (Editors), Collision betweebetweenn calcite-graphitcalcite-graphitee pairpairss iinn metasedimentmetasedimentss frofromm ththee Africa. In: M.P. Coward and A.C. Ries (Editors), Collision Tectonics. Blackwell, Oxford, pp 329-49. Mgama Hills, Hills, southern southern Kenya. Kenya. Geochimica Geochimica and and Cosmochimica Cosmochimi­ Tectonics. Blackwell, Oxford, pp 329-49. Sweatman, T.R., Long, J.V.P., 1969. Quantitative electron Acta,ca 49Acta,, 1553-60. 49,1553-60. Sweatman, T.R., Long, J.V.P., 1969. Quantitative electron probe microanalysis of rock forming minerals. Journal of BridgesBridges,, C.R.CR.,, 19821982.. GemstoneGemstoness ooff EasEastt AfricaAfrica.. InternationalInternational probe microanalysis of rock forming minerals. Journal of Petrology, Gemological Symposium Proceedings (1982)(J 982).. 266-75266-75.. Petrology, 1010,, 332-79332-79.. Walsh, J., 1960. Geology of the area south of the Taita Hills. CahenCahen,, L.L.,, SnellingSnelling,, N.J.N.J.,, DelhalDelhal,, J.J.,, VailVail,, J.R.J.R.,, 19841984.. The Walsh, J., 1960. Geology of the area south of the Taita Hills. Geological Survey of Kenya, Report 49. 26pp. geochronology and evolution of Africa. ClarendoClarendonn PressPress,, Geological Survey of Kenya, Report 49. 26pp. OxfordOxford.. ZwartZwart,, H.J.H.J.,, 19671967.. ThThee dualitdualityy ooff orogeniorogenicc beltsbelts.. Geologie en Mijnbouw, 46, 283-309. CartwrightCartwright,, I.I.,, BarnicoatBarnicoat,, A.C.A.C,, 19861986.. ThThee generatiogenerationn ooff quartz­quartz- Mijnbouw, 46, 283-309. normativnormativee meltmeltss anandd corundum-bearincorundum-bearingg restiterestitess bbyy crustalcrustal anatexisanatexis:: petrogenetipetrogeneticc modellinmodellingg basebasedd oonn aann examplexamplee fromfrom [[ManuscriptManuscript received 12 January 19911991. .J] ththee LewisiaLewisiann ooff north-wesnorth-westt ScotlandScotland.. Journal of Metamorphic Petrology, 33,, 79-9979-99.. F.G.A. your key to the fascinating world of Gemmology

The Qemmological 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 I 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. rpfeose complete and return to the Gemmological Association Training Scheme. 1 " 27 Greville Street, London EC1N 8SU England Tel: (071) 404 3334. Fax (071) 404 8843

Name

Position

Company

Address

Telephone L. .j 498 J.J. Gemm.,Gemm., 1991,22,81991,22,8

PaperPaper GemsGems J. EadieEadie

NortNorthh GlasgowGlasgow CollegeCollege (Barmulloch(Barmulloch Campus),Campus), 186186 RyeRye Road,Road, GlasgowGlasgow G21G21 3JY3JY

Figs.Figs. 1·31-3 A selectionselection ofof postagepostage stampsstamps depictingdepicting gemgem crystalscrystals andand cutcut stones,stones, miningmining activitiesactivities andand corals.corals.

StampStamp collectingcollecting isis ononee ofof thethe world'sworld's mostmost maymay bbee substituted.substituted. SometimesSometimes thethe requisitrequisitee stampstamp popularpopular hobbieshobbies butbut becausbecausee ofof thethe prodigiousprodigious cannotcannot bebe boughtbought singlysingly fromfrom thethe dealerdealer bubutt cancan issuesissues ofof worldworld stamps,moststamps, most philatelistsphilatelists nownow resortresort onlyonly bebe purchasedpurchased asas partpart ofof a setset ofof stamps.stamps. eithereither toto collectingcollecting a singlesingle countrycountry oror thethe classics,classics, OtherOther topicstopics whichwhich maymay bbee ofof interestinterest toto thethe oror inin moremore recentrecent timestimes collectingcollecting stampsstamps basedbased gemmologistgemmologist are:are: upouponn a themetheme oror topic.topic. ForFor a gemmologistgemmologist thethe topictopic 1.1. varietiesvarieties ofof coralcoral (approximately(approximately 150150 stamps);stamps); 'Gem'Gem Crystals'Crystals' seemsseems toto bebe anan obviousobvious choice.choice. 2.2. diamondsdiamonds andand associatedassociated materialmaterial suchsuch asas mining,mining, TheseThese areare toto bebe foundfound onon stampsstamps displayingdisplaying thethe treatmenttreatment plain,plant, grading,grading, etcetc (approximately(approximately 3030 crystalcrystal form,form, thethe facetedfaceted gemgem oror both.both. stamps).stamps). ThereThere areare somesome twotwo hundredhundred stampsstamps featuringfeaturing AnyAny readerreader whowho wouldwould likelike a listlist ofof stampsstamps onon anyany gemgem crystalscrystals andand asas expectedexpected thethe mostmost commoncommon gemgem ofof thethe aboveabove mentionedmentioned topicstopics maymay obtainobtain a freefree crystal,crystal, quartzquartz andand itsits varietiesvarieties areare toto bebe foundfound onon nono copycopy fromfrom thethe authorauthor atat thethe above address.address. lessless thanthan 3232 stamps.stamps. ForFor a collectioncollection unmountedunmounted HappyHappy collecting.collecting. mintmint stampsstamps areare preferablpreferablee althoughalthough inin somesome casescases costcost mightmight precludprecludee thisthis,, andand v.f.u.v.f.u. (very(very finefine used)used) [Manuscript received 14 JuneJune 1991.]1991.] J. Gemm.3 1991,22,8 499 500500 J.J. Gemm.,Gemm., 1991,22,81991,22, 8

EmeraldsEmeralds fromfrom ColombiaColombia (Part(Part 3)*3)* George Bosshart Bosshart Giibelin Gemmological Laboratory, Maihofstrasse 102, CH-6000 Lucerne 9, Switzerland Gübelin Gemmological Laboratory, Maihofstrasse 102, CH-6000 Lucerne 9, Switzerland

AbstractAbstract berylberyl latticelattice (Cr(Cr = V,V, withwith thethe CrNCr/V ratioratio foundfound toto bebe IntroductionIntroduction (Part(Part 1)1) rangingranging fromfrom 4.54.5 toto 0.5,0.5, inin extremeextreme casescases fromfrom aboutabout 1010 AI.Al. TheThe historyhistory ofof ththee ColombianColombian emeraldemerald minesmines toto 0.1).0.1). Iron,Iron, however,however, hashas barelybarely beenbeen detecteddetected inin thethe A2.A2. TheThe geographicalgeographical locationlocation ofof thethe emeraldemerald UVNISUV/VIS absorptionabsorption spectraspectra ofof ColombianColombian emeralds.emeralds. ThoughThough generallygenerally presentpresent iinn slightlyslightly largerlarger amountsamounts occurrencesoccurrences 3 + thanthan Cr + ironiron doesdoes notnot recognizablyrecognizably influenceinfluence thethe 2+ 3+ colourcolour (little(little Fez+ andand possiblypossibly somesome Fe3+Fe positionedpositioned inin B1.Bl. TheThe emeraldemerald depositsdeposits andand theirtheir geologicalgeological the,axialthe axial channelschannels ofof thethe ring-silicatring-silicatee structure).structure). environmentenvironment A detailed presentation presentation of ofthe the currently currently known known internal inter­ B2.B2. HypothesesHypotheses ofof emeraldemerald genesisgenesis nal characteristicscharacteristics (inclusions(inclusions andand growthgrowth structures)structures) isis B3.B3. TheThe minemine workingsworkings supplementedsupplemented byby a discussiondiscussion ofof identificationidentification prob­prob­ lemslems withwith treatetreatedd emeraldsemeralds andand thethe disclosuredisclosure ofof thethe GemmologicalGemmological propertiesproperties (Part(Part 2)2) treatmenttreatment duringduring transactionstransactions iinn thethe wholesalewholesale andand retailretail C1.CI. Morphology,Morphology, qualityquality andand sizesize ofof ththee emeraldemerald trade. crystalscrystals AllocationAllocation ofof thethe emeraldsemeralds toto individualindividual ColombianColombian mines on the basis of inclusion patterns does not appear C2.C2. ChemicalChemical composition,composition, chromophorechromophore andand tracetrace mines on the basis of inclusion patterns does not appear possiblepossible iinn mostmost instancesinstances.. However,However, thethe differentiationdifferentiation elementelement contentscontents ofof ColombianColombian emeraldsemeralds fromfrom otherother naturalnatural emeraldsemeralds C3.C3. LightLight absorption,absorption, colourcolour andand fluorescencefluorescence (such(such asas thosethose fromfrom ththee PanjsherPanjsher ValleValleyy exhibitingexhibiting veryvery C4.C4. OpticalOptical valuesvalues andand densitydensity similarsimilar (s,(s,l,g l,g)) three-phasethree-phase inclusions)inclusions) oror fromfrom difficult,difficult, CS.C5. InclusionsInclusions andand growthgrowth characteristicscharacteristics modernmodern hydrothermalhydrothermal andand fluxflux syntheticssynthetics isis shownshown toto bebe feasiblfeasiblee byby a combinationcombination ofof microscopy,microscopy, refractometry,refractometry, TreatmentsTreatments (Part(Part 3)3) andand absorptionabsorption spectrometryspectrometry (UVNIS(UV/VIS andand NIR/MIR),NIR/MIR), D.D. Oil,Oil, ultrasonicultrasonic andand heatheat treatmentstreatments assistedassisted byby chemicalchemical analysisanalysis onlyonly inin thethe mosmostt difficultdifficult cases.cases. SafeSafe identificationidentification ofof authenticity,authenticity, treatment,treatment, andand originorigin ofof emeralds,emeralds, however,however, isis increasinglyincreasingly becomingbecoming DiscussionDiscussion thethe tasktask ofof thethe expertsexperts inin thethe specializedspecialized laboratory.laboratory. E.E. DifferentiationDifferentiation ofof thethe ColombianColombian emeraldsemeralds fromfrom TheThe mineralogicalmineralogical definitiondefinition ofof emeraldemerald asas a yellowishyellowish naturalnatural emeraldsemeralds ofof otherother origins,origins, syntheticsynthetic emer­emer­ toto bluish-greebluish-greenn varietyvariety ofof naturalnatural berylberyl isis shownshown toto bebe aldsalds andand emeraldemerald imitationsimitations valid forfor any any Cr Cr and and V-containing V-containing variety variety except except possibly poss­ ibly thethe rare,rare, absolutelyabsolutely chromium-freechromium-free (V,Fe)-beryls(V,Fe)-beryls AcknowledgementsAcknowledgements (modification of of the the former former definition definition of type of typeII emerald): II emer­ BibliographyBibliography ald): inin manymany ofof thethe preferredpreferred ColombianColombian emeralds,emeralds, chromiumchromium isis clearlyclearly dominateddominated byby vanadiumvanadium (CrN(Cr/V ratioratio AbstractAbstract < I).1). However,However, chromiumchromium hashas a higherhigher efficiencyefficiency ofof A condensedcondensed historicalhistorical andand miningmining surveysurvey isis followedfollowed colorationcoloration thanthan vanadiumvanadium andand a muchmuch higherhigher oneone thanthan by aa compilationcompilation of ofthe themost most notable notable crystals crystals of Colombian of Col­ ironiron ionsions inin thethe variousvarious substitutionalsubstitutional andand interstitialinterstitial ombian emeraldsemeralds everever foundfound andand ofof thethe detailsdetails ofof theirtheir latticlatticee sitessites ofof berylberyl.. CrCr influencesinfluences colourcolour eveevenn atat veryvery chemicalchemical composition.composition. A summarysummary ofof thethe elementalelemental low tracetrace levels. levels. substitutionssubstitutions andand theirtheir effectseffects onon thethe outlinedoutlined rangerange ofof AnAn extensiveextensive anandd up-datedup-dated selectionselection ofof literature,literature, gemmological data data is is given. given. coveringcovering allall aspectsaspects cited,cited, completescompletes ththee synopsis.synopsis. SpecialSpecial emphasisemphasis isis placedplaced onon thethe causecause ofof thethe famous,famous, vividlyvividly greengreen coloration,coloration, i.e.i.e. onon thethe selectiveselective absorptionabsorption TheThe introductionintroduction toto thisthis reviewreview isis basedbased onon thethe studystudy ofof a fractionfraction ofof thethe of orange-redorange-red and and violet violet light, light, dictated dictated by minor by minor contents con­ extraordinarilyextraordinarily extensiveextensive literatureliterature onon ColombianColombian emeralds.emeralds. TheThe mainmain partpart ofof thethe paperpaper (Part(Part 2)2) containscontains datadata collectedcollected andand findingsfindings tentsof the of thechromophoric chromophoric elements elements Cr and Cr V andsubstituting V substitut­ achievedachieved overover manymany yearsyears iinn thethe SSEFSSEF LaboratorLaboratoryy inin Zurich.Zurich. 3+ ingfor for Al AI3+ in octahedrally in octahedrally coordinated coordinated sites of thesites of the ParrPart 3 dealsdeals withwith thethe difficultiesdifficulties encounteredencountered iinn identifyingidentifying treatedtreated emeraldsemeralds andand withwith thethe disclosuredisclosure necessarynecessary whenwhen sellingselling themthem andand willwill *This*This iiss a papepaperr hashas beenbeen publishepublishedd inin The Journal inin threethree parts.parts. TheThe discussdiscuss thethe possibilitiespossibilities ofof differentiationdifferentiation betweebetweenn ColombianColombian andand otherother completecomplete bibliographybibliography waswas presentepresentedd withwith PartPart 1l.. naturalnatural emeraldsemeralds andand thethe syntheticsynthetic emeralds.emeralds. J. Gemm., 1991, 22, 8 501

Treatments extreme conditions the internal pressure of the fluid D. Oil, ultrasonic and heat treatment inclusions or the intrinsic strain caused by in- A few inevitable words to the subject of 'oil homogeneous chemical composition or geotectonic treatment. Regrettably it is not true that only a small stress can lead to a rupture of the stone. The number of Colombian emeralds are improved in coloration of emerald by chromium and vanadium, appearance. In principle all fractures and fissures on the other hand, is largely resistant to heat and is are subjected to filling with colourless oils, Canada not affected by irradiation. balsam etc. Success is largely dependent on the quality of the emeralds. Qualitatively good emer­ alds cannot show an improved appearance simply Discussion because they do not possess oilable (surface- E. Differentiation of Colombian emeralds from other reaching) tension cracks. For objective quality emeralds and emerald substitutes is easily managed as assessment, emeralds should be de-oiled before any nearly every Colombian stone shows the character­ transaction is finalized (Figure 22). Oil removal is istic jagged three- and multi-phase inclusions and easily achieved with warm acetone. These fracture definite growth structures, has low to (at most) fillings are not permanent. They readily evaporate medium refractive index and density values and or alter in other ways, either chemically or optically exhibits no iron spectrum, with the exception of an (oxidation in air, reaction with alcohol, soapy water, occasional weak Fe3+ line at 374 nm or a trace of the cosmetics etc., Figures 23 and 24). Ultimately there Fe2+ band centred at about 800 nm. In addition, the is a general need for subsequent retreatment. absorption edge at the transition to the general According to laboratory experience, the private absorption and the absorption minimum in the UV owner may be puzzled by the deteriorated appear­ are at extraordinarily low wavelength positions. ance of the oiled emerald sold to him as untreated. However, three- and multi-phase inclusions are He may even become annoyed by the slow or by no means found exclusively in Colombian emer­ sudden 'generation' of shockingly flashing cracks, alds. Resembling them the most are the healing as he can prove that he did not damage the emerald. fissures observed in Afghani and Pakistani emer­ The experience with his 'sensitive' emerald can alds. The expert can usually distinguish the pat­ make him so sceptical that he is deterred from terns by various details. More effective identifica­ buying other gemstones. Any explanation by the tion properties of Pakistani emeralds are the high jewellery staff after the sale to the effect that oil refractive index and density values (due to their treatments have long become customary will de­ elevated contents of Fe, Cr and alkalis) as well as the finitely provide little solace. North-American sales dissimilar mineral and wallrock inclusions (albite personnel seem to be better trained with respect to and carbonaceous shale in Colombian emeralds and disclosure of gemstone treatments than the Euro­ talc, molybdenite, hematite, chromite, magnetite pean trade. and recently also gersdorffite (NiAsS, cubic) in the New treatment methods have recently made Pakistani stones). Pyrite and carbonates are com­ progress. Open cracks are permanently filled and do mon to emeralds of both mining districts. not turn turbid (but may appear blue in transmitted A greater problem of identification appear to be light and show orange flashes in reflected light). the Afghani emeralds from the Panjsher Valley, little These techniques make use of artificial resins and known up to now. Their inclusions are similar to hardeners and similar stabilizing substances. and their refractive index and density values hardly It must be stated that emeralds are not necessarily higher than the Colombian ones. However, the endangered by the use of ultrasonics. Beryls are not absorption spectrum is clearly different (Figure 4: more brittle or friable than many other gemstones. UV absorption edge and minimum at higher They even lack a proper cleavage. The reaction of wavelengths, distinct Fe3+ band at 374.5 nm plus emeralds to any mechanical stress is dependent - as Fe2+ bands at about 840 nm (o) and 800 nm (e); iron in the case of oil treatment - primarily on their content of the Panjsher emerald of 0.789 ct con­ quality. Every kind of gemstone with definite firmed by microprobe partial analysis). tension and cleavage cracks presents a higher risk The gemmological data of certain Brazilian and than a fine stone without flaws. But even these can Australian emeralds are often congruent with those be damaged under extreme circumstances, for of the Colombian stones. But, because of their instance when a sharp girdle of a diamond baguette different types of inclusions, identification presents exerts pressure on a set emerald (Figure 25). no more difficulty than that of emerald imitations Emeralds are also no exception when required to (made of Cr-doped YAG, zirconia, glass) or of tolerate high temperatures (^700°C), irregular in­ composite stones (e.g. soudé 'emeralds' made of fluence of heat and thermal shock during jewellery quartz/green glass/quartz; emerald-green rough work. The weak basal cleavage in beryl then causes made of assembled and dye-filled crystals). On the the stone to disintegrate into turbid slices. In these other hand, modern flux and especially hydrother- 502 J. Gemm., 1991,22,8

mal synthetics may pose problems which can no longer be solved except with the help of UV/VIS and near- and mid-infrared absorption spectra, chemical analyses and possibly ESR spectra. While the determination of origin, based on the colour and microscopic, chemical and physical properties mentioned above, is comparatively sim­ ple for emeralds from Colombia, substantiation of the specific mine is nearly impossible. Article 5 of the CIBJO Rules (1988) demands an unequivocal declaration as to emerald treatment with coloured oils or the permanent filling of cracks with artificial substances of the new generation. Evidence of each and every kind of treatment with Fig. 23 Covering of oil, fat or Canada balsam on an extended the microscope and UV lamp is often ambiguous. tension crack in a Colombian emerald, transformed Iridescent reflection colours, for instance, are not into a semi-solid, ugly-looking white crust. Width of photomicrograph about 0.40 mm. specific: the orange flash on the fissure shown in Figure 13 looks very similar to those from 'Opticon' sealed cracks yet it is not due to this treatment. Systematic application of the CIBJO nomenclature regulations therefore is virtually impossible. Mic- rospectrophotometric cathode-luminescence tests (Ponahlo 1989) could help here if they would facilitate differentiation of the various chemical compounds used. Metal foils formerly applied to the pavilion of mounted emeralds are rarely encountered nowa­ days. They have not been durable, just like the modern green lacquers or iridescent coatings on emeralds, and are also recognizable at moderate magnification. Many gemmologists and gemstone dealers do not Fig. 24 Iridescent and greenish reflective oil film on a tension appear in a 'moral' position to accept without crack, in an advanced state of dendritic dessication. contradiction the unintentionally broad mineralo- The owner of the emerald noticed the puzzling rainbow gical definition of emerald plainly as green beryl phenomenon one day with the bare eye. Length of oil film 2.2 mm. variety (i.e. without any restriction as to the hues and saturations of green). The author, nevertheless, insists on the fact that small quantities of Cr3+ (Al3+oct.), being the cause of the green colour of all type I emeralds, appreciably participate in the coloration of type II emeralds also, due to the greater colouring effect of Cr than V or Fe. If there was a type of green beryl which might not be designated as an emerald, it should only be the V, Fe-beryls, absolutely free of Cr. Because of their chromium traces, most natural vanadium beryls, such as the ones from Eids voll (Mjösa Lake, Norway), Emmaville (New South Wales), Salininha (Bahia) or Gandao (Mohmand Agency, Pakistan), must be allocated to the emerald type II and should thus be called emeralds as well. Fig. 25 Extensive irregular breakage caused by the strong unilateral pressure of a diamond baguette on this emerald, formerly a centre stone in a ring. Develop­ ment of breakage from the point of contact (the Acknowledgements asymmetric indentation below the girdle) over the The author thanks the following gentlemen for entire left crown side of this Colombian emerald, free from cracks and poor in inclusions. Length of the constructive suggestions: Dr D. Schwarz, Ouro notch approximately 2.65 mm. Preto (Brazil), now Idar-Oberstein, Mr W Schäfer, J. Gemm., 1991,22,8 503

Ottobrunn, Dr K. Schmetzer, Munich, Dr W. published in the Goldschmiede-Zeitung (Rühle Quellmalz, Dresden (Germany), Prof. Dr G. Diebener Verlag, Stuttgart, 1990, nos. 4,6,8), bene­ Niedermayr, Vienna (Austria), Prof. Dr E. Gübelin, fitted from the primary English translation by Mrs Meggen, Prof. Dr H.A. Stalder, Berne, and Dr H.A. E. Stern, London, and reviewing of the final Hänni, Basle (Switzerland). Thanks are returned to updated version by Mr E. Boehm, Los Angeles the latter for figures 1,7,9-12,14,15,19-23 and for (presently Lucerne, Switzerland). the partial EMX analysis of the Panjsher emerald of Figure 4, and to D. Schwarz for the EMX data on Corrigenda the Gachalâ emeralds. The author also appreciates On p.416 above, first column, 4th line, for 'that of the new chemical data on parisite specimens (e.g. on chromium Fe3+'read 'that of chromium and Fe3+'. the inclusions pictured in Figure 13) worked out by On p.418 above, second column, line 13, for Prof. Dr WB. Stern, Prof. Dr R. Guggenheim '(Figure 10)'read '(Figure 16)'. (Basle) and Dr A. Peretti (Lucerne). The original article 'Smaragde aus Kolumbien', [Manuscript received 19 March 1990.] 504 J. Gemm., 1991,22,8

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

OBITUARY K. Scarratt and PG. Read participating in various Mr Johannes S. Hermans, FGA (D.1981), Panel Discussions. E. Emms was involved in discus­ Delft, The Netherlands, died recently. sions on Diamond Grading. Mr Bjarne Jensen, FGA (D.1963), Bergen, For the enthusiastic gemmologist the Poster Norway, died in October 1990. session provided excellent opportunities to view Mr Gerald Leybourn-Needham, FGA (D.1980 and to discuss with exhibitors the results of recent with Dist.), Aston by Budworth, died in May 1991. research and new discoveries. There were some 90 Mr Henry McNeilly, FGA (D.1929), Belfast, displays from a wide spread of countries. N. Ireland, died in February 1990. To mark the Diamond Jubilee of the GIA, David Mr Akseli Valta, FGA (D.1973), Helsinki, Callaghan (our Chairman) presented to Bill Boya- Finland, died recently. jian (GIA President) a Herbert Smith refractometer for their collection of historical instruments. NEWS OF FELLOWS The evening functions were produced in the On 12 June 1991 Mr Michael O'Donoghue gave grand manner and included a fashion show hosted a talk entitled 'Gemstönes' to the Meopham Histor­ by cultured pearl interests from Japan and America ical Society. and also a gala 'Maestro and Masterpieces: Italian On 11 to 13 June 1991 Mr Michael O'Donoghue Jewels of the Opera', a dinner party and display and Mr Peter Reed lectured at two courses held by hosted by Italian jewellery organizations and the the Precious Stone Training Services. Platinum Guild International. Beautiful jewels, On 13 to 15 September 1991 Alan Hodgkinson, dresses and models! The overall theme was 'Facing David Larcher, Sharon Longden and Ken Stirton the Future' and every aspect of gemstones and participated in the National Exhibition of Time jewellery from the mine to the retail mall was held at the British Horological Institute, Upton featured. There was something for everyone in this Hall, Nr Newark, Notts, with an exhibition of gem superbly organized extravaganza - congratulations testing. The event proved to be very successful with and thanks to the GIA. a record attendance. MEMBERS' MEETINGS THE GIA INTERNATIONAL London GEMOLOGICAL SYMPOSIUM On 2 July 1991 at the City Conference Centre, 76 This very successful event was held in Los Mark Lane, London EC3R 7JN, a Pearl Evening Angeles from 20-24 June 1991 in conjunction with was held. Mr Alan Jobbins gave an illustrated the Conclave of the American Gem Society. There lecture on pearls, followed by reports from Nicholas were over 1800 representatives (from 45 countries) Sturman on pearl testing by X-rays and Alan Clark from the international gemmological fraternity and on the newly devised Pearl Quality Report. the jewellery industry. The programme comprised four concurrent feature presentations all day Friday Midlands Branch and Saturday with four concurrent panel discus­ On 20 September 1991 at Dr Johnson House, sions on the Sunday morning. As with most all- Bull Street, Birmingham, a talk was given by Mr embracing conferences, the problem was to choose F Deitch of Mikimoto entitled 'Pearls'. which one of the simultaneous lectures to attend - all four were always of considerable interest. British North West Branch input was by K. Scarratt and E.A. Jobbins in the On 18 September 1991 at Church House, Gem Identification sessions, D.J. Callaghan and Hanover Street, Liverpool 1, Dr J. Franks gave an R.R. Harding in the Period Jewellery sessions, with illustrated lecture on the Smithsonian Museum. [. Gemm0 1991,22,8 505

FORTHCOMING MEETINGS | London 3-4 November 1991 Conference and Presentation of Awards

Meetings will be held at the City Conference Centre, 76 Mark Lane, London EC3R 7JN, on the dates set out below. Full details and topics of lectures will be circulated prior to each meeting. Tuesday 28 January 1992 Tuesday 10 March 1992 Wednesday 13 May 1992 Tuesday 9 June 1992 Tuesday 24 November 1992

Midlands Branch Meetings to be held at Dr Johnson House, Bull Street, Birmingham. Further details from David Larcher on 021 554 3871. 15 November 1991 Mr J. Gosling. The Guyana Lapidary Project5 17 January 1992 Members' practical evening 21 February 1992 Mr Clive Burch. (Subject to be announced) 20 March 1992 Mr David Callaghan. (Subject to be announced) 10 April* 1992 Annual General Meeting followed by lecture * NB. This meeting has been arranged for the second Friday of the month because of the Easter holiday.

North West Branch Meetings to be held at Church House, Hanover Street, Liverpool 1. Full details from William Franks on 061-928 1520. 20 November 1991 Annual General Meeting 15 January 1992 David Pelham. 'On small gold mines' 19 February 1992 Helen Fraquet. Amber' 18 March 1992 Dr Jeff Harris. An aspect on diamonds' 17 June 1992 'Exchange and Mart'. Buying and selling of books, crystals and instruments, plus social evening 16 September 1992 Adrian Klein. 'Emerald' 21 October 1992 Dr Jamie Nelson. 'Optical attributes of a diamond' 18 November 1992 Annual General Meeting 506

GEM DIAMOND EXAMINATION 1991 The Preliminary Trade Prize for the best Pre­ In the 1991 Gem Diamond Examination 28 liminary candidate of the year under the age of 21 at candidates qualified. The names of the successful 1st June 1991, who derives her main income from candidates are as follows: activities essentially connected with the trade has Ann M. Allnutt, Chislehurst. been awarded to Anne Margaret Bailey of Rugby. Jose Miguel Bernad Soria, Zaragoza, Spain. Gloria Blanch Papaceit, Barcelona, Spain. DIPLOMA Liza Boyadjian, London. Anna Brooks, Watford. Qualified with Distinction Jose Antonio Casa Royo, Alfaro (La Rioja), Spain. Ma Ester Alvarez-Palacios, Salinas (Asturias), Ivan L. Charatan, Hackney. Spain. Bruce J. Copestick, Harpenden. Rene Gerard de Winter, Amsterdam, Caroline E. Findlay, Edinburgh. The Netherlands. John Mainwaring Henry, Bolton. Anura S. Edirisuriya, Dickwella, Sri Lanka. David J. Hollanders, Maidenhead. Linda Lee Galloway, Hong Kong. Yvonne Holton, Edinburgh. Rafel Ginebra i Molins, Vic, Spain. Ana Ma Lopez Gracia, Barcelona, Spain. Virginia Hogguer, Alphen aan den Rijn, Blancanieves Luzondo Olea, Tolosa (Guipozcoa), The Netherlands. Spain. Sandra J. Keating, Willowdale, Ont., Canada. Eduardo Moreno Rastrero, Logrono, Spain. Alec J. Mason, Retford, Nottingham. Brigitte CE. Pfeiffer, London. Rajendra A. Pattni, Nairobi, Kenya. Trevor Rackley, Northampton. Simon Schmidt, London. Anna Ma Ruiz Domenech, Torredembarra, Spain. Carolyn L. Stewart, Hong Kong. Ahad Sayed, Brentford. Stig E. Sundin, Bergen, Norway. Louise Shafar, Glasgow. Peter J. Wates, Coulsdon. Fatehchand Jivanlal Shah, London. Alison D. Williams, Abinger Common. Evelyn Sim, Singapore. Hong Chung Wong, Hong Kong. Lesley Skinner, Stenhousemuir. Qinfang Xue, Wuhan, China. Stephen Spencer, Nottingham. Mingxing Yang, Wuhan, China. Kevin. G. Williams, Edinburgh. Nean E. Wilson, Longniddry. Qualified Michael Wright, Watford. Arlan R. Abel, Minneapolis, Minn., USA. Mei Wan Wu, Harlow. Suzanne Adams, Sutton. Christopher Arno, Williamsville, N. Y, USA. Evangelia Anastassiou, Maroussi, Greece. EXAMINATIONS IN GEMMOLOGY 1991 Ekaterini Andersson, Athens, Greece. The 1991 Gemmology examinations were held at Alexander Arbisman, Selsdon. 62 centres in 26 countries throughout the world. Henry N. Atkinson, London. 552 candidates sat the Preliminary Examination of Sang-DukBae, Seoul, Korea. whom 341 (61%) qualified and 429 candidates sat Lisa J. Bailey, Birmingham. the Diploma Examination and 211 (48%) qualified, Aristea Bakayianni-Sabou, Athens, Greece. 17 with Distinction. Chantai Ball Edwards, Cheltenham Spa. In the opinion of the Examiners, no candidate Claire A. Barratt, Gillingham. achieved the high standard required to warrant the Frieda McNaughton-Bascombe, Hong Kong. award of the Tully Medal. Vassilis Bassioudis, Thessaloniki, Greece. The Anderson/Bank Prize for the best non-trade Spencer Benham, Isle of Man. candidate of the year in the Diploma Examination Colette 2fc Bensimon, London. has been awarded to Peter J. Wates of Coulsdon, Benoit Bouvier, Cornwall, Ont., Canada. Surrey. Heather K. Boyd, Manchester. The Diploma Trade Prize for the best Diploma Michelle A. Bradley, Norwich. candidate of the year who derives his main income Anna Brooks, Watford. from activities essentially connected with the Jewel­ Corrall E. Cage, London. lery trade has been awarded to Anura S. Edirisuriya Daniel Waite Campbell, Bedminster. of Dickwella, Sri Lanka. Amalia Campomanes Eguiguren, Alicante, Spain. The Anderson Medal for the best candidate of Begona Campos Novergues, Valencia, Spain. the year in the Preliminary Examination has been Andres Candela Alcover, Valencia, Spain. awarded to Wun Mo Seong of Daejon, Korea. Bonnie S.K. Chan, Hong Kong. Gemm., 1991,22,8

Members having gained their Diploma in Gemmology or the Gem Diamond Diploma (FGA or DGA) may now apply for use of the Coat of Arms on their stationery or within aiivertisments.

Laboratory members are also invited to apply for use of the Laboratory logo.

It is still a requirement of GAGTL, in accordance with the Bye Laws, that written permission be granted by the Council of Management before use.

Members interested in further information please contact:

Mrs. MJ. Martin

Gemmological Association and Gem Testing Laboratory of Great Britain • 27 GREVILLE STREET, (SAFFRON HILL ENTRANCE), LONDON EC1N 8SU •

Tel: (071) 404 3334 Fax:(071)404 8843 508 J. Gemm., 1991,22,8

Chi Keung Raymond Chan, Hong Kong. Jacqueline Ichniowski, Ellicott City, Md., USA. Nga Yee Chan, Hong Kong. Yuko Ito, Kanagawa-ken, Japan. Mahaveer Singh B. Chauhan, Jaipur, India. Neerja Jain, Birmingham. Kit Ling Connie Cheng, Hong Kong. Thomas Ake Jakobsson, Huddinge, Sweden. Siu Hing Cheng, Hong Kong. Cynthis C.V. Jameson, Bethesda, Md., USA. Roy Shuk-Hung Chiu, Hong Kong. Bindu Kejriwal, London. Kam King Chow, Hong Kong. Abdul Jabbar Khan, Bombay, India. Ourania Christaki, Volos, Greece. Priti Khimji, London. Terence Y.W Chu, Hong Kong. Andrée Killias, Hong Kong. Sucheta M. Chudawala, Bombay, India. Hiroyuki Kimura, Tokyo, Japan. Tsz Kin Chung, Hong Kong. Margaret A. King, Isle of Lewis. Tony Cipriani, St Laurent, Quebec, Canada. Pik Sim Kwan, Hong Kong. Sarah E. Clifton, Birmingham. Mui Lak Margaret Lai, Hong Kong. Janette M. Colborne, Brisbane, Qld., Australia. Jose Lajara Lopez, Valencia, Spain. Mark A. Colingwood, Bradford. Radka Lalovska-Koundourou, Athens, Greece. Stephanie Collins, New Maiden. Kwong Ki Lam, Hong Kong. Ian Combe, Haddington. Christina Keturah Lam-Pakstun, Brisbane, Qld., Martha D'Alessandro, Rio de Janeiro, Brazil. Australia. Gamini De Silva, London. Yan Wah Glady Lau, Hong Kong. R V.D.PR.F Neelamanee De Silva, Moratuwa, Mee Sim Lucia Maisie Lau, Hong Kong. Sri Lanka. Carl Laürie-Lynch, Birmingham. Stuart G. Dennis, London. Padraic Lavin, Ballaghaderreen, Eire. Ahsha Devnani, Kuala Lumpur, Malaysia. Isabelle Leblans, Ottignies, Belgium. Pablo Dhir, Nairobi, Kenya. King To Lee, Hong Kong. Setu Hasmukh Doshi, Bombay, India. Mary FA. Lee, Addlestone. Valerie S. Egner, London. Annette I. Lehnert, Tiefenbach, Germany. Dora Pang English, Hong Kong. Janine Lentz, Veenendaal, The Netherlands. George G. Evangelou, London. Wing Sum Leung, Hong Kong. Deborah Everest, Aldershot. Kam Yui Dick Li, Hong Kong. Carita L. Falck, Helsinki, Finland. Shang I. Liu, Hong Kong. Lucia Ferrer Mas, Alicante, Spain. Mo Yu Lo, Kowloon, Hong Kong. Robert H. Fixter, Lincoln, Nebr., USA. Ann Denise Long, Colchester. Sara E. Flint, Leeds. Kok On Loong, Butterworth, Malaysia. Pui Man Foo, Hong Kong. David C. McConnachie, Glasgow. Brenda C. Foster, St. Albans. Katsuya Maeda, Kakogawa-shi, Japan. Neil Franklin, Newcastle-upon-Tyne. Wing Han Windy Mak, Hong Kong. David E. Fromming, Aylesbury. Carina Manjavacas Canego, Barcelona, Spain. Hideali Fukushima, Tokyo, Japan. James Gerard Mansfield, London. Chung Min Newson Fung, Hong Kong. Susana Marti Muntane, Barcelona, Spain. Bauke G. Gaastra, Leiden, The Netherlands. Jacqueline N. Mathieson, Edinburgh. Lai Gajadeera, Boralesgamuwa, Sri Lanka. Hiroshi Matoba, Nara-City, Japan. Robert Ben-rong Gau, Taipei, Taiwan, China. Lisa Matthews, London. Elizabeth Georgiadou, Volos, Greece. Shilpa Mehra, London. Maria K. Ghisi, Athens, Greece. Reshma Mehta, Hong Kong. Sophia Gofa, Athens, Greece. Azmet F Merchant, Bombay, India. Enrique Gomez Lopez, Zaragoza, Spain. Mark Michallat, Shipley. Miranda J. Grant, Edinburgh. Beverly Mitchell, London. Alan A. Green, Kidlington. Silvia Molera Reig, Barcelona, Spain. Christopher M. Green, Slough. Junko Mori, Hyogo Pref, Japan. Rajasinghe S. Gunasekara, Colombo, Sri Lanka. Stephanos Mourogiannis, Athens, Greece. Wai Ming Ha, Kowloon, Hong Kong. Hilda May-Mei Mueller, Karlsruhe, Germany. Rebecca Mary Anne Hare, Fleet. Chee Keong Ng, Hong Kong. Adrian L. Hendry, Stansted. Tahmineh Nikookar, West Vancouver, Canada. Peter G. A. Hobbs, Lavenham. Theresa A. Nolet, Sault Ste Marie, Ont., Canada. Elisabeth G. Hoogendoorn, Houten, Felipe Ortega Pino, Valencia, Spain. The Netherlands. Mamiko Oura, Tokyo, Japan. Charlotte T. Hunter, Northampton. Shing Chung Dominic Pang, Hong Kong. J. Gemm., 19913 22, 8 509

Roy John Pasini, N. Olmsted, Ohio, USA. Xinmin Zhao, Wuhan, China. Pankaj Patel, London. Johannes C. Zwaan, London. Sharon M. Peers, London. Keith Penton, London. PRELIMINARY Ma Angeles Pi Gregorio, Barcelona, Spain. Richard J. Pool, York. Qualified Cecilia Pople, Guildford. Veli Sakari Aalto, Nairobi, Kenya. Claire A. Redgrove, Selsey. Erling Skaar Aasen, Molde, Norway. Janine Reimers, Johannesburg, S. Africa. Sheik Rashid Ahmed Al-Kalifa, Bahrain. (Lesley) Clare Rigby, Bolton Abbey. Pedro A. Alcolea Rubio, Cartagena, Spain. Ma Paz Roca Tudela, Valencia, Spain. Nick Aldridge, Gravesend. John W.S. Rogers, Stroud. Julie A. Alford, Taunton. Neva Devi Rohmer, Hong Kong. Debra Arden, Ashton under Lyne. Alan F. Rowlands, Calgary, Alta., Canada. Michael J. Armstrong, Whitley Bay Samuel J. Sabbagh, London. In-Ryul Bae, Seoul, Korea. Steven E. Sabbagh, London. Jin Yee Baek, Daejon, Korea. Tar ja Aulikki Salmi, Helsinki, Finland. Vinod K. Baid, London. Ramon Sanahuja i Ribo, Barcelona, Spain. Anne M. Bailey, Rugby. Jeannine Sanchez Comerma, Alicante, Spain. Maj-Britt Baker, Hove. Elisenda Santacreu Rull, Lleida, Spain. Frederik CS. Bakker, Zwaagdijk, Judy Shalvi, Hong Kong. The Netherlands. Yasushi Shinjo, Osaka, Japan. Pamela J. Ball, Hong Kong. Charlotte R. Simmons, Huntingdon, Md., USA. Michelle Banks, Exeter. Rika M. Spencer, Helsinki, Finland. Frieda McNaughton-Bascombe> Hong Kong. Hirofumi Takano, Toshimo-ku, Tokyo, Japan. David A. Beavan, Bournemouth. Mari Takeda, Tokyo, Japan. Victoria L. Bedwell, London. Carol S. Tamblin, Liskeard Michelle L. Bellamy, Swansea. Ay Lin Tan, Penang, Malaysia. Ma Dolores Belmonte Monino, Murcia, Spain. Takako Tanigaki, Osaka City, Japan. Maria Benissi, Athens, Greece. Audrey Tees, Glasgow. Deli A. Boerema, Beek en Donk, The Netherlands. Lucilla Thomas-Everard, London. Cristian Bou Dominguez, Castellon, Spain. Sui Ching Tsang, Hong Kong. Christine L. Bradford, Hassocks. Miwako Tsuda, Takarazuka City, Japan. Nikki Bradford, Hassocks. Kazuo Tsurita, Osaka, Japan. Antonio Brenes Lanza, Valencia, Spain. Ma Victoria Uriarte Terol, Alicante, Spain. Jordi Bruguera De La Pena, Barcelona, Spain. Ma Victoria Uribe Molto, Alicante, Spain. Susan M. Buncher, Tai Po, NT, Hong Kong. Hester van den Haak, Krimpen A/D Yssel, Denis Burrow, Gravesend. The Netherlands. Jae Kyoung Byun, Seoul, Korea. Michael J. Vaughan, Budleigh Salterton. Beverley A. Capper, Paignton. Vivianne M.M. Veenemans, Arnhem, Stuart M. Carter, Bristol. The Netherlands. Rafael Casal Bordes, Valencia, Spain. Marco Vesters, s'Hertogenbosch, The Netherlands. Seung Yuen Samuel Chan, Hong Kong. Mark Waller, Bradford. Wai Pin Chan, Hong Kong. Keith Walter, Peebles. Kwai Hing Chan, Hong Kong. Simon J. Washbrook, Manchester. Kwei Wing Fion Chan, Hong Kong. Caron J. Wasserman, London. Nga Yee Chan, Hong Kong. Kathleen Webster, London. Chan Siu Lily Chan, Hong Kong. Lizanne Welch, Taunton. Hang Chau, Hong Kong. Andrew Wells, Banstead. Shun Chung Chau, Hong Kong. Eddy Wenting, Wehl, The Netherlands. Susannah Chenevix-Trench, Hong Kong. Siu Por Wong, Hong Kong. Pin Hoo Cheng, Hong Kong. Kit Yee Kitty Yeung, Hong Kong. Chi Ho Cheung, Hong Kong. Machiko Yonehara, Hyogo Pref, Japan. Kam Kwan Cheung, Hong Kong. Marie-Claire M. Zander, Sao Paulo, Brazil. Mei Ping Liann Cheung, Hong Kong. Rafal Zebrowski, Toronto, Ont., Canada. Laura Chiampesan, London. Linxia Zhang, Wuhan, China. Oi Han Esther Chin, Hong Kong. Fan Zhang, Wuhan, China. Hang Sun Cho, Daejon, Korea. 510 J.Gemm., 1991,22,8

Kyu Hyeon Cho, Daejon, Korea. Noel R. Geoghegan, Wellesbourne. Yong-SangCho, Seoul, Korea. Anastasis L. Georgiou, Famagusta, Tricomo, Dong-Geun Choi, Seoul, Korea. Cyprus. Kyung Sug Choi, Kwangju, Korea. Stavros Georgiou, Lefkara, Cyprus. Meyeoung Yeoung Choi, Dae j on, Korea. Rafel Ginebra i Molins, Vic, Spain. Seog Hoon Choi, Kyungju, Korea. Valerie J. Goddard, Alford. Sook Kyong Choi, Pusan, Korea. Francis G. Gray, Edinburgh. Pui Wing Choi, Hong Kong. Janette F. Green, Binley, Coventry. Chun Hung Chow, Hong Kong. Pauline Groeneveld, Giessenburg, Shui Wah Chow, Causeway Bay, Hong Kong. The Netherlands. Lai Ying Chow, Hong Kong. Ilse C. Grondahl, Helsinki, Finland. Wai Mui Chow, Hong Kong. Yu Guimei, Wuhan, China. Philip J. Chown, Sevenoaks. Winfried Gutmannsbauer, Allschwil, Switzerland. Helen E. Christian, Bolton. Wai Ming Ha, Kowloon, Hong Kong. Josephine A. Clayton, London. Sabine Haberli, Bottmingen, Switzerland. Joseph Connelly, Edinburgh. Andrew D. Haigh, Nettleham. Carolyn Cooper, Hong Kong. Ingvald Harkestad, Bergen, Norway. Ann Cordery, London. Richard J. Harris, Carlisle. Chusri Cox, Hove. Orit N. Hayes, Manchester. Jeremy E Crabbe, Hong Kong. Jennifer V. Henricus, Hong Kong. Marta Crespo Vilaro, Barcelona, Spain. Suzanne C. Hicks, Yardley, Birmingham. Virginia Gai Cullen, Nairobi, Kenya. Po Mi Avis Ho, Hong Kong. DeeDee Cecilia Cunningham, Toronto, Ont., Jeung Hee Hong, Taegu, Korea. Canada. Xie Hongzhi, Wuhan, China. Nita Daryanani, Hong Kong. Sadayuki Hoso, Osaka City, Osaka, Japan. Frederic P. Daubechies, London. Mark Hudson, Ickenham. Bryn Day, Oldham. Helen S. Hughes, London. Kees de Boer, Beek (Ubbergen), The Netherlands. Chak Lun Hui, Hong Kong. Laurenria Melissa de Jongh, The Hague, Stephen J. Humphreys, Biggin Hill, Westerham. The Netherlands. Kyu-Young Hwang, Seoul, Korea. Luisa De La Torre Lopez, Tarragona, Spain. Mi Hee Hwang, Daejon, Korea. Asha Devnani, Kuala Lumpur, Malaysia. Soon Sun Hwang, Pusan, Korea. Rosemary O. Dharmaratne, Colombo, Sri Lanka. Hiroyoshi Ishida, Takatsuki, Osaka, Japan. Birgit WM. Doesborg, Schoonhoven, Takeshi Iwata, Hyogo Pref, Japan. The Netherlands. Cynthis C.V. Jameson, Bethesda, Md., USA. Setu Hasmukh Doshi, Bombay, India. Myung Won Jang, Seoul, Korea. Lucy N. Downing, Fulham, London. D. A. Jayananda, Colombo, Sri Lanka. Alison Earnshaw, Tonbridge. Steven L. Jordan, Boston. Siripala Edirimannege, Colombo, Sri Lanka. Julia Kalinin, Ealing, London. Michelle L. Embleton, Basildon. Che Mei Kam, Hong Kong. Gail Emslie, Hong Kong. Hyun Sook Kang, Daejon, Korea. Nora Engel, Geneva, Switzerland. Joo- Yeun Kang, Seoul, Korea. John W Faithfull, Leicester. Kyung Sil Kang, Pusan, Korea. Joaquim Falco Rovira, Llanca, Spain. Kiron Kapila, Nairobi, Kenya. Charoulla Fantis, Bethnal Green, London. Niilo Karkkainen, Espoo, Finland. Abigail A. Farley-Howson, Aylesbury. Sandra J. Keating, Willowdale, Ont., Canada. Juan J. Fernandez Jativa, Alicante, Spain. Chen Kesheng, Wuhan, China. Marisa Fernandez Perez, Barcelona, Spain. Hee Souk Kim, Chonan, Korea. James Clark Fernbach, Schenectady, New York, Hei Jong Kim, Seoul, Korea. USA. Jee Sue Kim, Daejon, Korea. H. W J. Fleuren, Polsbroek, The Netherlands. Jong Pil Kim, Daejon, Korea. Melissa Friedland, Omaha, Nebr., USA. Myoung Sub Kim, Taegu, Korea. Suzy Fry, London. Apostolia Kiroudi, Athens, Greece. Mary Mei Ling Fu, Hong Kong. Jacoba E. Klaassen-de Ruiter, Waddinxveen, Ho Cheuk Fung, Hong Kong. The Netherlands. Arien Der Garabedian, Hackney, London. Garfield D. Kneebone, Penzance. Pilar Garrigosa Laspenas, Barcelona, Spain. Anya K. Koetsier, London. J. Gemm., 1991,22,8 511

Peter A. Kohn, Oxford. Stephen R. Mason, Birmingham. Sarah Joy Ku, Hong Kong. Shilpa Mehra, London. Leena Kuumola, Stockholm, Sweden. Reshma Mehta, Hong Kong. Chi Ming Kwan, Hong Kong. Aiden Melarkey, Northampton. Ho Taeg Kwon, Pusan, Korea. John J. Melinn, London. Anna-Maiji Lahtela, Hamina, Finland. Samuel P. Meza, Glasgow. Tim Mui Lai, Hong Kong. John O. Mitchell, Istanbul. Sai Mui Lai, Hong Kong. Shuji Morikawa, Osaka City, Osaka, Japan. Yi Oi Lai, Hong Kong. Ma Dolores Morillo-Verlarde Taberne, Barcelona, Tuovi Tellervo Laiti, Lahti, Finland. Spain. Pun Ho Lam, Kowloon, Hong Kong. Brian A. Morris, Oswestry. Ka Loi Celine Lam, Hong Kong. Kyung Ju Na, Daejon, Korea. Suet Lai Lam, Hong Kong. Liisa Nevalainen, Espoo, Finland. Yik Him Lam, Hong Kong. Frances Newman, London. Bernard Lang, Basel, Switzerland. Soon Hoh Ng, London. Barry Larkins, London. Kwok Yin Ng, Hong Kong. Jörgen Larsen, Lannavaara, Sweden. Tahmineh Nikookar, West Vancouver, BC, Canada. Hok Keung Lau, Hong Kong. Theresa A. Nolet, Sault Ste Marie, Ont., Canada. Ying Chi Lau, Hong Kong. Anthony L. O'Shea, Ruislip. So Sum Angelina Jessica Law, Hong Kong. Graham A. Oakley, Wrangbrook, Pontefract. Isabelle Leblans, Ottignies, Belgium. Gemma Oldfield, London. Hyeon Jin Lee, Daejon, Korea. Ma Isabel Olias Pertusa, Barcelona, Spain. Hyung Jeong Lee, Dae j on, Korea. Maung Thein Lwin Oo, Singapore. Siu-Kuen Lee, Kowloon, Hong Kong. Michèle J. Orsi, London. Sook Jin Lee, Dae j on, Korea. Antonio J. Ortega Marin, Cieza, Spain. Sun Sook Lee, Daejon, Korea. Bing Pang, Hong Kong. Yong Woo Lee, Daejon, Korea. Kyung Ok Park, Seoul, Korea. Young Mee Lee, Daejon, Korea. Mi Kyeong Park, Pusan, Korea. Ossi A. Leinonen, Viantie, Finland. Jagdish Ishverbhai Patel, Wimbledon, London. Michael T. Y Leung, Hong Kong. Rekha Mahesh Patel, Nairobi, Kenya. Man Tai Raymond Leung, Hong Kong. Rajesh Jamnadass Pattni, Eldoret, Kenya. Lai Ping Leung, Hong Kong. Andrea Pawlyna, Hong Kong. Aggeliki Leventopoulou, Kalamaki, Athens, Elise E. Peios, Kingswood. Greece. Monica Pereda Soler-Cabot, Barcelona, Spain. Shek Kee Li, Hong Kong. Rosa Maria Perez Merchante, Valencia, Spain. Soung Taek Lim, Seoul, Korea. Maria Perpina Bomboi, Valencia, Spain. Ravindranath Liyanage, Colombo, Sri Lanka. Cecilia Pople, Guildford. Mo Yu Lo, Kowloon, Hong Kong. Jagdish Prajapati, London. Sara Anne-Marie Lodge, Birmingham. Susanne L. Preece, Trowbridge. Kok On Loong, Butterworth, Malaysia. Louise C. Prior, London. Roberto Lopez De Alda-Saez, Tarragona, Spain. Graham S. Proffitt, Liverpool. Angel Manel Lopez i Calvo, Reus (Tarragona) Julian Read, Goole. Spain. Keith C. Reffeil, Barnhurst. Cho Lin Arlene Luke Ting, Hong Kong. Paul R. Rietveld, Bergen Op Zoom, Jane F. Luxton, Bath. The Netherlands. Edward J. McCarthy, Cambridge. Claudia J. Rijkelijkhuizen, Bosch en Duin, Malini P. McDonald, Tampa, Fla., USA. The Netherlands. Suzanne M. McDonald, Edinburgh. Chantal Rochat-Huguenin, Lausanne, Switzerland. Neil Reid McFarlane, Alloa. Franklin Rodriguez Ortiz, London. Jane Mcllleron, Bedfordview, S. Africa. Aar to Roppanen Tohmajarvi, Finland. Jonathon N. McLelland, Bradford. Ma Teresa Ros Gonzalez, Barcelona, Spain. Janet E. McQueen, Lurgan, Co Armagh. Ramon Rossell Ma Andorra La Vella, Spain. Chris M. Makoundoul, Stockholm, Sweden. John T Rossiter, Weston-Super-Mare. James G. Mansfield, London. Ignasi Rubio Barris, Girona, Spain. Luis Fernando Martinez Caravaca, Barcelona, Kyeong Won Ryu, Daejon, Korea. Spain. Ali Mohammed Safar, Bahrain. Juan Carlos Martinez Vela, Jumilla, Spain. Francesc Sancho Montserrat, Saut Bol de 512 J. Gemm., 1991, 22, 8

Llobregat, Spain. Errol J. Walker, Oldham. Jose Luis Santolaya, Barcelona, Spain. Simon J. Washbrook, Manchester. Katja C. Schneider, East Twickenham. Caron J. Wasserman, London. Tay Sun See, Hong Kong. Maria J. Weisenborn, Den Bosch, Joung Hee Seo, Daejon, Korea. The Netherlands. Wun Mo Seong, Daejon, Korea. Isabel H. White, Tunbridge Wells. Clara Ma Serra Molla, Valencia, Spain. Cas Jelle Wiebinga, Amsterdam, The Netherlands. Nuria Serret-Pinacho, Barcelona, Spain. Angélique C. Wijne, Schoonhoven, Kul Bhushan Sharma, Lusaka, Zambia. The Netherlands. Hyun Kwon Shin, Daejon, Korea. Catharina A.H. Winkelmolen, Schoonhoven, Wai Chung Siu, Hong Kong. The Netherlands. Cornells Slui, Krimpen A/D Ijssel, Man Yee Bess Wong, Kowloon, Hong Kong. The Netherlands. Ming Kin Wong, Hong "Kong. Brendon James Smith, Swindon. Miu Wan Mueller Wong, Hong Kong. Chak Tong Anthony So, Hong Kong. Jei-Sung Woo, Seoul, Korea. Jeong Sun Sohn, Seoul, Korea. Bik Yee Liza Woo, Hong Kong. Gary Spanbok, London. Yin Yung Wu, Hong Kong. Riita M. Spencer, Helsinki, Finland. Zhang Yabin, Wuhan, China. Robert J. Stainton, Edinburgh. Young Mee Yi, Daejon, Korea. Nick Stamatiadis, Athens, Greece. So Ying Yin, Hong Kong. Jonathon E S toner, Bradford. Yoichi Yoshikawa, Kobe-shi, Hyogo Pref, Japan. Elizabeth Strachan, London. Byeong Mi Youn, Seoul, Korea. Josephine Stuifzand, Twello, The Netherlands. Kwai Lan Catherine Yu, Hong Kong. Hideko Sugihara, Osaka, Japan. Chai Hung Teresa Yuen, Hong Kong. Ay Lin Tan, Penang, Malaysia. Sun Ki Yun, Seoul, Korea. Kati Tarma, Helsinki, Finland. Tak Yi Yung, Hong Kong. Maja Clarissa Te Velde, Langerak, Fabrizia Zanettin Barbin, Geneva, Switzerland. The Netherlands. Rafal Zebrowski, Toronto, Ont., Canada. Elizabeth Thompson, Leeds. Liu Zhao, Wuhan, China. Bjorn T Thorbjornsen, Bergen, Norway. Johannes C. Zwaan, London. Johanna H. Thuis, Schoonhoven, The Netherlands. Maria M. Tiilikainen, Ireland. Sebastia Timoner Espuga, Terrassa, Spain. MEETING OF THE COUNCIL OF Darren M. Topham, Brighton. MANAGEMENT Peter J.B.C. Travis, London. At a meeting of the Council of Management held Ki Lun Allan Tsang, Hong Kong. on 12 June 1991 at E.A. Thomson (Gems) Ltd, Wai Mo Tse, Hong Kong. Chapel House, Hatton Place, London EC1N 8RX, On Na Anna Tse, Hong Kong. the business transacted included the election to Kwok Wing Tse, Hong Kong. membership of the following: Maria Tsipoura-Vlachou, Athens, Greece. Keith A. Tucker, Ilkley. Fellowship William J. Tucker, Douglas, Isle of Man. Fan, Siu-Kam, Kowloon, Hong Kong. D.1989 Lonneke van der Hülst, Krommenie, Kangas, Anne K., Helsinki, Finland. D.1990. The Netherlands. Geertruida J. Van Hillo, Almere-Buiten, Ordinary Membership The Netherlands. Cattell, Nicla M.L. V., Kettering. Simone J.C. Van Keulen, Amsterdam, Corbett, John A., Edgbaston. The Netherlands. Daryanani, Nita, Hong Kong. Hans T. Van Lamoen, Hertogenbosch, Emmett, John L., Pleasanton, Calif., USA. The Netherlands. Pakzad, Mohammad A., London. Lorraine Van Papen, Guildford. Parkinson, Frederick, Leighton Buzzard. Vasso Vassilakou, Athens, Greece. John Vaughan, London. At a meeting of the Council of Management held Michael Vaughan, Whitby, Ellesmere Port. on 17 July 1991 at 1 Burlington Gardens, London Alida J. Velthoven, Uven, The Netherlands. W1X 2HP, the business transacted included the Miguel Angel Vila Llopis, Alzira (Valencia), Spain. election to membership of the following: J. Gemm., 1991,22,8 513

Fellowship MEETING OF THE TRADE LIAISON Reveliotis, Christos, Athens, Greece. D. 1990. COMMITTEE At a meeting of the Trade Liaison Committee Ordinary Membership held on 4 July 1991 at 87 Hatton Garden, London Ben-Zur, Eitan, London. EC1, the business transacted included the election Carter, Stuart M., Bristol. to membership of the following: Cerins, Andris, Cambridge. Gold Laboratory Membership Comersford, Jessie, Alexandria, Egypt. Roselaar & Co., c/o LDB, 100 Hatton Garden, Grossman, Julie F., Hounslow. London EC1N8NX. Gunasekara, S., Boulder, Colo., USA. Bernard Schipper BV, Kalverstraat 36-38, 1012 PD Halai, Amy, Solihull. Amsterdam, The Netherlands. Kassam, Sultan M., London. Richard Shepherd & Co., Suite 123, 100 Hatton Koundourou, Ratka, Athens, Greece. Garden, London EC IN 8NX. Prajapati, Jagdish, London. Ordinary Laboratory Membership At a meeting of the Council of Management held Charles Mathews (Lapidaries) Ltd., 7 Hatton on 21 August 1991 at 27 Greville Street, London Garden, London EC1N 8AT. EC IN 8SU, the business transacted included the election to membership of the following: Ordinary Membership Berreux, Cedric, La Chaux-de-Fonds, Switzerland. De Granville, Francesca, Oklahoma City, Okla., USA. Denson, Keith, Oldham. Fox, Rosemary T., Brighton. Gautama, Surinder, Ilford. Milne-Buckley, Deborah J., Chertsey. Salama, Susan E, Beckenham. Schlüssel, Joseph L., New York, NY, USA. Thorbjornsen, Bjorn T., Bergen, Norway. Tillakaratne, Adikari M.N.K., Kano, Nigeria.

Transfers - FGA to FGA, DGA ^KENT-INSTITUTE Allnutt, Ann M., Chislehurst. D.1962. Boyadjian, Liza A., Heston, D.1989. iSOFART&DESIGN Charatan, Ivan L., London. D.1990. Copestick, Bruce J., Harpenden. D.1990. Findlay, Caroline E., Edinburgh. D.1988. GEMMOLOGY Henry, John M., Bolton D.1990. Hollanders, David J., Nelson. D.1990. AT KIAD ROCHESTER Holton, Yvonne, Edinburgh. D.1986. Pfeiffer, Brigitte CE., Isleworth. D. 1989. We run a two-year part-time theoretical Rackley, Trevor, Brackley. D.1990. and practical course in preparation for Shafar, Louise, Eaglesham. D.1990. the Diploma Examination of the Sim, Evelyn, London. D.1990. Gemmological Association of Great Skinner, Lesley, Stenhousemuir. D. 1990. Britain. Spencer, Stephen R., Woodborough. D.1990. At the end of the first year of study, Williams, Kevin G., Edinburgh. D. 1983. the student will sit the preliminary Wilson, Nean E., Longniddry. D. 1990. examination. The successful candidate Wright, Michael J., Watford. D. 1990. can then prepare for the Diploma Certificate and on obtaining this will Transfers - Ordinary Membership to Diamond then be eligible to become a Fellow of the Membership Gemmological Association (FGA). Blanch, Gloria, London. For further information please contact Brooks, Anna T, Watford. Christopher Chalk or Brian Hill on 0634 Sayed, Ahad, Brentford. 830022 Ext 210, or Christopher Chalk at Shah, Fatechand J., London. home on 0227 70244. Wu,MeiW, Harlow. 514 J. Gemm0 1991,22,8

Wé look after ajj your insurance PROBLEMS For nearly a century T. H. March has built an whether it be home, car, boat or pension plan. outstanding reputation by helping people in business. We would be pleased to give advice and As Lloyds brokers we can offer specially tailored quotations for all your needs and delighted to visit policies for the retail, wholesale, manufacturing and your premises if required for this purpose, without allied jewellery trades. Not only can we help you with obligation. all aspects of your business insurance but we can For a free quotation ring Mike Ward or Jim Pitman also take care of all your other insurance problems, on 071-6061282.

T. H. March and Co. Lid. Saint Dunstan's House, Carey Lane, London EC2V 8AD. Telephone 071-606 1282 & Lloyd's Insurance Brokers J. Gemm, 1991,22,8 515

Pearls Coral Amber Bead Necklaces Carvings Cameos Mineral Specimens 7^& The World of Gemstones Ruppenthal (U.K.) Limited Gemstone of every kind, cultured pearls, coral, amber, ivory, bead necklaces, hardstone carvings, objets d'art, silver gemset jewellery, antique jewellery, mineral specimens, mineral and gemstone study collections. We offer a first-class lapidary service. We are also interested in purchasing any unusual gemstones, gemstone necklaces, objets d'art, figurines, cameos, intaglios, antique jewellery from any period, antiquarian books of the gemstone industry etc.

6 Warstone Mews New London Showroom, Warstone Lane 3rd Floor, 20-24 Kirby Street, Birmingham Bl8 6JB Hatton Garden, London EC IN 8TS Tel: 021-236 4306 Tel: 071-405 8068/6563 Fax:021-2121905 Fax:071-8315724

Antique Jewellery Modern 18ct and 9ct Jewellery and All Gemstones #BB# Jtfshrut Gftms PRIMA STONES KAWAN PEARL COMPANY Exporters, Importers & Manufacturers of Pearls,Diamonds and Precious Stones. SUPPLIERS OF PRECIOUS AND SEMI­ Specialist supplier in PRECIOUS STONES TO THE TRADE. Genuine Natural, Oriental IMPORTERS OF FINE EMERALD, Gulf Pearls, Necklaces, BOTH CUT AND UNCUT. Dropshape, Button Shape. SPECIALISTS TO THE JOBBING JEWELLER, SERVICES INCLUDE Ask for our free catalogue; "Pearls-The Queen of Jewels" LAPIDIARY AND SETTING.

79 Dhanji Street, 4th Floor, Sutaria Bhaven, Prima House, 48 Roxburgh Terrace BOMBAY-400003 (INDIA) Whitley Bay, Tyne & Wear, Telephone: 323473/8125527-8110724 England NE26 1DS Telegram: 'SMTTESH' Telephone and Fax: (091) 2514240 Telefax: (9122) 8123914 516516 J.J. Gemm.,Gemrn., 1991,221991, 22,, 8 GEMDATAGEMDATA -- UPDATEUPDATE 44 A computercomputer programprogram forfor gemgem identificationidentification andand studystudy NowNow containscontains additionaladditional diagnosticdiagnostic datadata onon inclusions,inclusions, spectra,spectra, pleochroism,pleochroism, luminescenceluminescence andand treatments.treatments.

NoNoww availablavailablee iinn ititss fourtfourthh updateupdatedd versionversion,, GEMGEMDAT DATAA iiss compiledcompiled iinn BASIBASICC 7.7.11 anandd wilwilll rurunn directldirectlyy frofromm MS-DOMS-DOSS oonn ananyy IBMIBM PC-compatiblPC-compatiblee computercomputer.. ItIt iiss designedesignedd ttoo helhelpp witwithh botbothh appraisalappraisal identificationidentificationss anandd gemmologicagemmologicall studies.studies. AAnn optionaoptionall updatupdatee ooff GEMDATGEMDATAA iiss availablavailablee eaceachh yearyear.. GEMDATGEMDATAisA is suppliesuppliedd oonn eitheeitherr a 5SIf4-inch Vi-inch double-sided,double-sided, double­double- densitdensityy diskdisk,, oorr a SV^-inc31fz-inchh diskdisk,, anandd containcontainss ththee followinfollowingg sectionsections:-s :- GeGemm anandd CrystaCrystall IdentificatioIdentificationn frofromm a databandatabankk ooff oveoverr 222200 gemgemss (now(now witwithh additionaadditionall datdataa oonn inclusionsinclusions,, spectraspectra,, pleochroispleochroismm andand luminescencluminescencee anandd treatments)treatments) GeGemm ComparisonComparisonss (side-by-sid(side-by-sidee displadisplayy ooff ththee constantconstantss anandd crystalcrystal systemsystemss ooff selecteselectedd gemsgems,, witwithh additionaadditionall datdataa oonn inclusionsinclusions,, etc.)etc.).. TableTabless ooff RRII anandd SSGG valuesvalues.. GeGemm CalculationCalculationss (SG(SG,, reflectivityreflectivity,, criticalcritical angleangle,, BrewsteBrewsterr anglanglee anandd gegemm weight/diameteweight/diameterr estimation)estimation) ThThee GEMDATGEMDATAA packagepackage,, completcompletee witwithh diskdisk,, operatinoperatingg notenotess anandd gegemm indexindex,, costcostss £96.0£96.000 + VATVAT,, postagepostage andand packing.packing. TToo orderorder youryour packagepackage pleaseplease useuse thethe couponcoupon providedprovided onon p.518p. 518 .. .~ ..re;t ~ GEMMOLOGICAGEMMOLOGICALL INSTRUMENTINSTRUMENTSS LTLTDD A divisiodivisionn ooff Thee GemmologicaGem mological l AssociatioAssociationn anan~d GeGemm TestinTesti ngg LaboratorLaboratoryy ooff GreaGreatt BritaiBritainn I 27 Greville Street, London EC1N 8SU. Telephone: 071-4043334 Fax: 071-404 8843 27 Greville Street, London EC1N 8SU. f Telephone: 071-404 3334 Fax: 071-404 8843 J.J. Gemm.,Gemm., 1991,22,81991, 22, 8 517517

CHRYSOBEflty

• ^&& C^, NQUAMAR/A/£ 4**v , ^.<& GARNET . f^ <% ^ v <^

Museums,Museums, EducationaEducationall EstablishmentsEstablishments ~neSiSenesis

& CollectorsCollectors *• LeadersLeaders inin gemmologicalgemmological education,education, specializingspecializing iinn intensivintensivee tuitiontuition,, frofromm scratcscratchh ttoo F.G.A.F.G.A. I havehave whatwhat isis probablyprobably thethe largestlargest rangerange DiplomDiplomaa iinn ninninee monthsmonths.. WWee cacann claiclaimm a veryvery ooff genuinelgenuinelyy rarraree gemstonegemstoness inin ththee UK­UK - highighh levelevell ooff passepassess includinindudingg DistinctionsDistinctions frofromm ApophyllitApophyllitee ttoo ZinciteZincite.. AlsAlsoo rarerare amongsamongstt ouourr studentsstudents.. •* WeWe organizeorganize a comprehensivecomprehensive programmeprogramme ofof syntheticssynthetics,, i.ei.e.. ApatiteApatite,, Scheelite,Scheelite, StudyStudy TourTourss foforr ththee studenstudentt anandd practisingpractising BismuthBismuth Germanate,Germanate, KnischKnischk kaa rubiesrubies gemmologistgemmologist., ttoo areaareass ooff gemmologicagemmologicall interest,interest, anandd a rangrangee ooff InamoriI namori.. includinincludingg AntwerpAntwerp,, Idar-ObersteinIdar-Oberstein,, SriSri LankLankaa anandd Bangkok.Bangkok. ListListss availablavailablee *• DealersDealers inin gemstonesgemstones andand rarerare specimensspecimens forfor NENEWW LISLISTT ofof inexpensiveinexpensive stonesstones botbothh ththee studenstudentt anandd ththee collectorcollector.. suitablsuitablee foforr STUDENTSTUDENTSS *• SuppliersSuppliers ofof gemmologicalgemmological instruments,instruments, especiallespeciallyy ththee worlworldd famoufamouss OPOPLL diffractiondiffraction (Pleas(Pleasee sensendd threthreee firsfirstt clasclasss stampsstamps)) gratingratingg spectroscopespectroscope., togethetogetherr witwithh a rangerange ofof bookbookss anandd studstudyy aidsaids.. AA.. JJ.. FRENCFRENCHH F.G.A.F.G.A . FFor or further further details details of ofthese these and and other other aflivities. activities, please please conlacl:-contacl:- GeGemm DealeDealerr & ConsultanConsultantt ColiColinn WinterWinter,, F.G.A.F.G.A.,, oorr HilarHilaryy TaylorTaylor,, B.A.B.A.,, 8822 BrookleBrookleyy RoaRoadd F.G.A.F.G.A.,, aatt GENESISGENESIS,, 2211 WestWest Street,Street, Epsom,Epsom, SurreSurreyy KT1KT188 7RL7RL,, EnglandEngland.. BrockenhurstBrotkenhurst,, HantHantss S04S0422 7RA7RA TelTel:: EpsoEpsomm (03727(03727)) 4297442974.. TelephoneTelephone:: 059023210590 232144 TelexTelex:: 923499234922 TRFRTRFRTT G attnattn GENS.GENS. 518 J. Gemm., 1991, 22, 8

PROMPT LAPIDARY GEMSTONES TO STUDY, SET, REPLACE AND COLLECT SERVICE! CUTS OLD, ANTIQUE, FANCY AND STANDARD Gemstones and diamonds cut to your SPECIMENS UNUSUAL, ODD, CURIOUS specifications and repaired on our AND INTERESTING premises. Large selection of gemstones including Variable selection rare items and mineral specimens in subject to availability stock. INDIVIDUAL SMALL SETS OF Valuations and gem testing carried out. Comparison colour simulants Mail order service available. and reference stones R. HOLT & CO. LTD. ENQUIRIES BUSINESS HOURS TEL 071 839 7635/081 946 2495 98 Hatton Garden, London ECIN 8NX Telephone 071-405 0197/5286 PERSONAL CALLERS Telex 21879 Minholt ONLY BY APPOINTMENT GEMDATA A computer program for gem identification The GEMDATA package by Peter Read is available through Gemmological Instruments Limited at £96.00 plus VAT, postage and packing. Postal rates are as follows: £3.50 UK and Eire; £4.00 Europe; £6.00 rest of the world.

Please supply copies of the GEMDATA Package, with 5.25/3.5 inch disk*

*I use a colour/monochrome monitor *I enclose remittance £ /debit my credit/charge card (tick appropriate box)

DO o@ D D\M * Delete as applicable Card No. _ Expiry date Name: Address: __ Post Code: To: Gemmological Instruments Limited, 27 Greville Street, London EC1N 8SU Tel: 071 404 3334 Fax: 071 404 8843 J.J. Gemm.Gemm.,, 1991,22,81991,22,8 519519

WHY DO 92 COUNTRIES REU

B,Because'ecaus e whethewhetherr yoyouu livlivee ihn1. EnglanEnglandd oorr ThailandThailand,, gemstonegemstoness anandd mineralmineralss araree jusjustt aass fascinatingfascinatin . . AnAndd nnoo otheotherr magazinmagazinee covercoverss ththee gegemm anandd jewelrjewelryy artartss liklikee LapidaryLapidanj Journal Journal.. EverEveryy monthmon;th,, you'lyou'lll heahearr frofromm ththee field'field'ss totopp expertexpertss aass thetheyy reporreportt ttoo yoyouu ththee lateslatestt discoveriediscoveriess iinn mineralogmineralogyy anandd gemologygemology.. LapidaryLapidary Journal Journal takes take yous yo onu o gemstonen gemston expedite expeditionsions, invites, invite yous yo intou int o studiostudioss ooff note notedd artisans artisans,, anandd thethenJl setsetss uupp shoshopp iinn youyourr owownn homhomee ttoo teacteachh yoyouu ththee mosmostt basibasicc ttoo ththee mosmostt revolutionarrevolutionaryy cuttincuttingg anandd jewelrjewelryy makinma1

ThThee World' World'ss Favorit Favoritee GemstonGemstonee MagazinMagazinee 520 J. Gemm., 1991,22,8 ANNOUNCEMENT Christopher \ Cavey & Associates Gernmologists, mineralogists and jewellery consultants Have moved their premises from Bond Street to Unit 177 Grays Antique Market 58 Davies Street London Wl Y 1AR Telephone: 071-495 1743

lPS 27s ^ AMçr

Dealers in AUSTRALIA Best (Zolour the gem stones of Best Quality the world Diamonds, Rubies, Sapphires, Emeralds, and most coloured gem stones ^^W Pearls & Synthetics. «^olî^ Calibrated Cut Stone & Mine Run Rough R.M.Weare j^g* Hip Sang Trading Co & Company Limited. 67 The Mount York. England. Y02 2AX. Champagne Arcade, Kimberley Road, Kowloon, Hong Kong Telephone 0904-621984. Telex: 57697 Yorvex.C Tel: 367 9747 Cable: "HIPSANGJEWL" Fax: 739 7654 Mailing Address: K.P.O. Box 96532, T.S.T. Hong Kong k Notes for Contributors The Editors are glad to consider original is consistent with clear indication of the articles shedding new light on subjects of content of the paper. It should be followed by gemmological interest for publication in the the names (with initials) of the authors and by Journal. Articles are not normally accepted their addresses. A short abstract of 50-100 which have already been published elsewhere words should be provided. Papers may be of in English, and an article is accepted only on any length, but long papers of more than the understanding that (1) full information as 10 000 words (unless capable of division into to any previous publication (whether in parts or of exceptional importance) are English or another language) has been given, unlikely to be acceptable, whereas a short (2) it is not under consideration for publication paper of 400-500 words may achieve early elsewhere and (3) it will not be published publication. elsewhere without the consent of the Editors. Twenty five copies of individual papers are Papers should be submitted in duplicate on provided on request free of charge; additional A4 paper. They should be typed with double copies may be supplied, but they must be line spacing with ample margins of at least ordered at first proof stage or earlier. 25mm all round. The title should be as brief as

ADVERTISING IN Rates per insertion, excluding THE JOURNAL OF VAT, are as follows: GEMMOLOGY Whole page £180 Half page £100 The Editors of the Journal invite Quarter page £60 advertisements from gemstone and mineral dealers, scientific Enquiries to Mrs M. Burland, instrument makers, publishers Advertising Manager, and others with interests in the Gemmological Association, gemmological, mineralogical, 27 Greville Street, lapidary and jewellery fields. London EC1N8SU. Volume 22 No. 8. October 1991

ThcJournal of Gemmology

Contents

An unusual assembled inclusion specimen R.C. Kammerling and J.I. Koivula 459

Contributions to a history of gemmology - Carl Peter Thunberg and Ceylon gemstones J. Sinkankas 463

The microscopic determination of structural properties for the characterization of optical uniaxial natural and synthetic gemstones. Part 3: Examples for the applicability of structural features for the distinction of natural and synthetic sapphire, ruby, amethyst and citrine L. Kiefert and K. Schmelzer 471

The growth of rubies in south-east Kenya RM. Key andJ.O. Ochieng 484

Paper gems J. Eadie 498

Emeralds from Colombia (Part 3) G. Bosshart 500

Proceedings of The Gemmological Association and Gem Testing Laboratory of Great Britain and Notices 504

Copyright© 1991 The Gemmological Association and Gem Testing Laboratory of Great Britain Registered Office: Palladium House, 1-4 Argyll Street, London W1V IAD

ISSN: 0022-1252

Produced by Green Belt Studios: Printed by Quadrant Offset, Hertford, England. Volume 22 Numbers 1-8 1990-1991

TheJournal of Gemmology

VOLUME 22 NUMBERS 1-8 1990-1991 INDEX

GEMMOLOGICAL ASSOCIATION OF GREAT BRITAIN 521 TheJourna l of Gemmology VOLUME 22

NUMBERS 1-8 1990-1991

CONTENTS [No. 1, January 1990] JOBBINS, E.A., SCARRATT, K., Some aspects of pearl production with particular reference to cultivation at Yangxin, China 3 KAMMERLING, R.C., KOIVULA, J.I., Star rhodolite garnet from Tanzania 16 KENT, D., Rewarding 'howlers' 19 SCHMETZER, K., Two remarkable Lechleitner synthetic emeralds 20 RINK, W., GIELISSE, P J., PLENDL, H.S., Coloration in electron-irradiated beryl 33 JOBBINS, E.A., XXII International Gemmological Conference, Italy 1989 38 Gemmological abstracts 41 Proceedings of the Gemmological Association of Great Britain and Association Notices 44 Letter to the Editor 56

[No. 2, April 1990] HÄNNI, H.A., A contribution to the distinguishing characteristics of sapphire from Kashmir 67 GOSLING, J.G., An unusual agate from Guyana 76 SCHMETZER, K., KIEFERT, L., Spectroscopic evidence for heat treatment of blue sapphires from Sri Lanka - additional data 80 HENN, U., BANK, D., BANK, F.H., Red and orange corundum (ruby and padparadscha) from Malawi 83 KARANTH, R.V., The diamond drill used in the Cambay bead industry 91 READ, P.G., Reflections on reflectivity 97 Gemmological abstracts 103 Book reviews 115 Proceedings of the Gemmological Association of Great Britain and Association Notices 116 Letters to the Editor 120

[No. 3, July 1990] The case of the disappearing gemstones 130 KOIVULA, J.I., FRYER, C.W., KANE, R.E., KAMMERLING, R.C., A black jade dilemma 131 HARDING, R.R., ZOYSA, E. GAMINI, Sapphirine from the Kolonne area, Sri Lanka 136 liFANTE, G., JAQUE, F., HOYOS, M.A., LEGUEY, S., Testing of colourless natural diamonds by room temperature optical absorption 142 SCHWARZ, D., EIDT, T., COUTO, P.A., The Brazilian emeralds and their occurrences: Socotô, Bahia 147 GRUBESSI, O., AURISICCHIO, C, CASTIGUONI, A., The Pharaohs' forgotten emerald mines 164 Gemmological abstracts 178 Book reviews 182 Proceedings of the Gemmological Association of Great Britain and Association Notices 184 Letter to the Editor 186

[No. 4, October 1990] KANIS, J., HARDING, R.R., Gemstone prospects in Central Nigeria 195 WON-SA KIM, Hematite inclusions in Eonyang amethyst from Korea 204 EADIE, J., Gemmological visual aids 207 MITCHELL, R.K., Bead buyers and parcel pickers filter set 212 SCHMETZER, K., KIEFERT, L., Water in beryl - a contribution to the separability of natural and synthetic emeralds by infrared spectroscopy 215 NELSON, J.B., Gemmological teaching in Hong Kong and China 224 READ, P.G., Detection of synthetic emeralds by thermal conductance 233 Gemmological abstracts 235 Book reviews 243 Proceedings of The Gemmological Association and Gem Testing Laboratory of Great Britain and Notices 246 Letter to the Editor 250 522 J Gemm., 1991,22

[No. 5, January 1991] COUPER, A.G., Colour as a guide to the composition of scapolite from Burma 259 KANIS, J., ARPS, C.E.S., ZWAAN, P.C., 'Machingwe': a new emerald deposit in Zimbabwe 264 CASSEDANNE, J.P., RODITI, M., Crystallized and massive rose quartz deposits in Brazil 273 FOSTER, G.V., BARKER, N.J., Suggestions for photographing jewellery 287 BROWN, G., Vulcanite or gutta-percha? That is the question 292 KOIVULA, J.I., KAMMERLING, R.C., FRITSCH, E., Gemmological investigation of a synthetic spinel crystal from the Soviet Union 300 Gemmological abstracts 305 Book reviews 310 Proceedings of The Gemmological Association and Gem Testing Laboratory of Great Britain and Notices 311 Letters to the Editor 321

[No. 6, April 1991] Sir Frank Claringbull 1911-1990 330 FARN, A.E., Pocahontas 331 HENN, U., REDMANN, M., BANK, H., Gem thaumasite from the Black Rock Mine, South Africa 334 NELSON, J.B., Gemmological teaching in Catalonia 337 KIEFERT, L., SCHMETZER, K., 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 344 BOSSHART, G., Emeralds from Colombia (Part 1) 355 HANNEMAN, W.W., Sodium polytungstate as a gemmological tool 364 KOIVULA, J.I., FRYER, C.W., KAMMERLING, R.C., Spessartine garnet in Brazilian topaz 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

[No. 7, July 1991] KAMMERLING, R.C., KOIVULA, J.I., Two strongly pleochroic chatoyant gems 395 NASSAU, K., Two types of historical traps: on 'Diamond Softening' and the 'Antiquity of Emerald Oiling' 399 PERERA, S.Z., PANNILA, A.S., GUNASEKERA, H.P.N.J., EDIRIWEERA, R.N., Anomalous behaviour of certain geuda stones during heat treatment 405 BOSSHART, G., Emeralds from Colombia (Part 2) 409 KIEFERT, L., SCHMETZER, K., The microscopic determination of structural properties for the, characterization of optical uniaxial natural and synthetic gemstones. Part 2: Examples for the applicability of structural features for the distinction of natural emerald from flux-grown and hydrothermally-grown synthetic emerald 427 Gemmological abstracts 439 Book reviews 448 Proceedings of The Gemmological Association and Gem Testing Laboratory of Great Britain and Notices 449 Letter to the Editor 451

[No. 8, October 1991] KAMMERLING, R.C., KOIVULA, J.I., An unusual assembled inclusion specimen 459 SINKANKAS, J., Contributions to a history of gemmology - Carl Peter Thunberg and Ceylon gemstones 463 KIEFERT, L., SCHMETZER, K., The microscopic determination of structural properties for the characterization of optical uniaxial natural and synthetic gemstones. Part 3: Examples for the applicability of structural features for the distinction of natural and synthetic sapphire, ruby, amethyst and citrine 471 KEY, R.M., OCHIENG, J.O., The growth of rubies in south-east Kenya 484 EADIE, J., Paper gems 498 BOSSHART, G., Emeralds from Colombia (Part 3) 500 Proceedings of The Gemmological Association and Gem Testing Laboratory Laboratory of Great Britain and Notices 504 J Gemm., 1989, 22 523

INDEX Compiled by Christine Woodward Alphabetical arrangement is letter-by-letter. Names of authors are printed in capitals, pages of abstracts and book reviews in italics. Special usages: above and below in cross-references indicate that the reference is to another subheading under the same heading, not a separate heading. A number in brackets following a page number indicates that there is more than one reference to the subject on the page.

Abernethy pearl, 6 AMARASINGHE, A.G.B., (see Bank, H., et al.) Absorption spectra (see Spectra, absorption) Amber: Actinolite: chatoyancy in, 395 —from Dominican Republic: fossil mushroom in, 308; snail —as an inclusion in emerald, 156, 158, 268, 271, 272 shells in, 443 ADAMSON, G.F.S., At the end of the rainbow: gold in —imitation (see Synthetic and simulated gemstones) Scodand, 243 Amblygonite: associated with rose quartz, 282, 283, 284 Afghanistan: —-montebrasite series, 372 —emerald from: in Panjsher Valley, absorption spectrum, 417; America: (see also: Argentina, Brazil, Canada, Chile, typomorphic features of, 238 Colombia, Domincan Republic, Guatemala, Guyana, Africa: (see also Angola, Botswana, Burundi, Kenya, Honduras, Mexico, Nicaragua, Peru, USA) Madagascar, Malawi, Morocco, Namibia, Nigeria, South —origin of jade artifacts found in, 375 Africa, Tanzania, Zaire, Zambia, Zimbabwe) Amethyst: associated with rose quartz, 278 —emerald crystals, imitation, from, 239 —from Canada: in Thunder Bay, Ontario, 114 —emeralds from: quantitative geochemical analysis of, 270 —citrine, 110 —grossular, parti-coloured, from, 444 —converted to citrine by heat, 42, 111 —Precambrian geotectonic units of southern and central, 265 —crystal morphology, 479 —quartz from: blue due to lazulite inclusions, 237 —growth structures: aid in distinction between natural and Agate: (see also Chalcedony) synthetic, 471, 482; planes, colour zoning in, 479, 480; —colour in Scottish, 237 twinning in, 481 —dendritic, in a doublet, 308, 461 —hematite inclusions in, 204, 205, 206 —from Germany: in the Harz region, 111; in Idar -Oberstem, —inclusions in, 204, 205, 206 106; in Saxony, 240 —from Korea: annual output, 204; distinction from Brazilian, —from Great Britain, 115, 237 204; found in géodes in granite; 204, hematite inclusions in, —from Guyana, 7Ç: cutting and polishing of, 79; geological 204, 205; X-ray powder diffraction data, 205, 206 occurrences, 77, 79; prospecting for, 77; unusual structure —sceptre crystals: from Malawi, 110; from Salem, of, 78, 79 Connecticut, USA, 239 —from Scotland: colour in, 237 —synthetic (see Synthetic and simulated gemstones) Agra diamond, 103 —from USA: in Arizona, at Fat Jack mine, 377; in eastern Ahrend, Mr R., Obituary, 184 states, geological occurrences of, 242, in Maine, 104, 110; Ajoite as an inclusion in quartz, 441 in New Hampshire, 104 AKAISHI, M., (see Miyamoto, M., et al.) Amphibole: (see also Kaersutite) AKIZUKI, A., Growth structure and crystal symmetry of —as an inclusion: in emerald, 241; in iolite, 305 grosssular garnets from the Jeffrey mine, Asbestos, Quebec, —rock, black: appearance in thin section, 133; chemistry of, 103 133; geological occurrence of, in association with jadeite, Albite: associated with emerald, 357 134; similarity of to black jadeite, 131, 134 —associated with ruby: electron microprobe analysis, 492; in Andalusite: mesoperthite, 489, 491 —from Brazil: a new location at Maricota, 105; occurrence in —in estimating temperature during metamorphism, 494 quartz, 106; in Paramirim, Bahia, 241; pleochroism in, 106 —as an inclusion in emerald, 421, 423, 501 —cat's-eye, 237 —from Kenya: associated with ruby, 492; gemmological —from South Africa: recovery of industrial grade in the properties of, / 78 Northern Transvaal, 114 Alexandrite: (see also Chrysoberyl) ANDERSON, B.W., Gem Testing, 243 —from Brazil: pegmatitic origin suggested, 105 Andesine: —colour filter test on, 213 —associated with ruby, 487, 491; electron microprobe Allanite as an inclusion: in emerald, 157, 158; in sapphire, 74, analysis, 492 372 —moonstone from India, 41 ALLEN, R. M., The Yogo sapphire deposit, 439 ANDREYENKO, E.D., (see Gromov, A.V., et al.) Almandine garnet: (see also Garnet) Angola: new diamond field at Lucapa, 308 —colour filter tests on, 213 ANNELS, A.E., BURNHAM, B.C.M., (Eds)., The —-pyrope as an inclusion in diamond, / 79 Dolaucothi gold mines, 379 Alpha-test thermal conductance meter, 233 Annual General Meetings: Alpine quartz, 237 —of the Gemmological Association: 1990, 246 AI2 Si05 polymorphs, 448 —of the Gemmological Association and Gem Testing ALVES, J., ( see Cassedanne, J.P.) Laboratory: 1990, 311 524 JGemm., 1991,22

Annual Reunion of Members and Presentation of Awards: —nephrite: from Cowell, 235; geological occurrence of, 375 1989,46; 1990,312 —opal from: from Coober Pedy, geology of, 382, world's Anorthite: as an inclusion in corundum, 86 largest from, 242; from Lightning Ridge, 379 ; occurrence ANTHONY, J.W., BIDEAUX, R.A.; BLADH, K.W., of gem quality, 237; opal fields, flooding in, 42; from NICHOLS, M.C., Handbook of mineralogy, Vol 1, 379 Yowah, Queensland, nobbies, 238; from Yundamindera, Apatite: fire opal, 105; —associated with: emerald, 357; rose quartz, 277, 282 —pearls, cultured: from Kuri Bay, NW coast, 235; from —bluish-green, sold as emerald, 308 Western Australia, 181 —cat's-eye, 308 —prasiolite from, 305 —colour filter test on yellow, 213 —prehnite from Kalkarig, 104 —dark green, from Brazil, 242 —Pool Mine, Western Australia, 41 —as an inclusion : in corundum, 114; in emerald, 157, 161; in —Poona WA and the seekers of its emeralds, 382 sapphire, 110, 201; in sapphirine, 138; in zircon cat's-eye, —rhodonite at Broken Hill, NSW,/77 108 —ruby in metamorphic rock, from the Harts Range, Northern —from Pakistan: in Nagar, pink, 447; new discovery in Territory, 109 pegmatites, 377 —sapphire from: in alkali basalt, crystal morphology of, 472; Aquamarine: (see also Beryl) bi-colour waterworn, 110; exploration for in New South —associated with rose quartz, 274, 277 Wales, 370; growth structures in, 472, 473, 475; —from Brazil: Jaqueto mine, Bahia, 447 origin of, 236; scatter of light by inclusions in, 397; star, 12- —colour filter tests on, 212, 213 rayed, 445; yellow multi-zoned crystal from Anakie, 42; —heat-treatment of, 403 zircon inclusions, age of, 236 —from India: 110; strained, 308 sphene from the Harts Range, Northern Territory, 374 —from Nigeria: 196; geological occurrences of, 197, 198 —stichtite from Tasmania, 440 —synthetic (see Synthetic and simulated gemstones) —titanite (see Sphene above) —from USA: Bighorn Mountains, 42 —turquoise from, 440 —from Zambia, 411 —variscite: from Dayboro, Queensland, 104; from Keppel ARANYAKENENI, P., Amphoe Bo Phloi. A new Thai Bay, 305 sapphire deposit, 103 —zircon from the Harts Range, Northern Territory, 178 Argentina: rhodochrosite from, 305, 378 Austria: ARJALAGUER, I., VILARDELL, D., Abaco para —emerald from: from Habachtal, chemical analysis of, 171, determination de los precios aproximados de los diamantes lattice parameters, 172, 173, 177; mineralization during con talla brilliante de River a Top Cape y de para las regional metamorphism, 238; in Untersalzbachtal, purezas de Internally flawless a Pique en el intervals de discovery of, 372 pesos de 0.25 a 3.00 quilates, 369 —Salzburg, minerals of, 115 —VILLARDEL, D., Abacos del peso aproximado y de Austrian Gemmological Research Institute, change of address, proporciones correctas de los diamantes con talla brillante 185 tipo Tolkowsky, 235 Aventurescence: in iolite, 305, 372, 395 ARPS, C.E.S., (see Kanis, J., et al) —in quartz, 440 Arsenopyrite: associated with rose quartz, 283 —in sunstone from Idaho, 239 Asterism: in ekanite, 239 Axinite: rediscovery of at Thornberry Mountain, California, —in quartz: 239; in rose, as diasterism, 286 USA —in sapphire: development and improvement of, 80; from Azurite: from Bou Beker mine, Morocco, 242 Queensland, 445; from Zaire, 372 —fine quality specimens from Chessy, France and Bisbee, —in star rhodolite, 16, 17 USA, 441 ATHINEOS, D., The orchid of the mineral kingdom, 439 —FMS-IGMS-MSA symposium on azurite and related copper ATTANASIO, D., FLAMINI, A., GRAZIANI, G., carbonates, 378 MARTINI, M., SCANDALE, E., Further observations on the Lennix synthetic emerald, 41 Bahrain (see also The Gulf): AUNG, Z., (see Huang, U.T., et al.) —pearls from, 4, 5 AURISICCHIO, C, (see Grubessi, O., et al.) BALFOUR, I., Famous diamonds of the world, XLII. The Australia: Argyle diamonds, 446 Agra, 103, The Taylor-Burton diamond, 235 —beryl, green, from Harry's Mine, NSW, 440 BANERJEE, A., (see also Rodrigues, P.) —chalcedony, dendritic, from Mt. Isa, 305 —Erkennungsmöglichkeiten von künstliche gefärbten —Chrysoprase from Marlborough, Queensland, 444 Lapislazuli, 235 —Cowell jade update, 235 Bangladesh: pearls from, 5 —diamonds from: from Argyle, champagne and cognac BANK, D., (see Henn, U., et al.) colours, 440; characteristics and mining of, 446; Australia's BANK, F.H., (see Bank, H., et aland Henn, U., et al) great treasure hunt, 235; computerized clarity analysis of, BANK, H., (see also Henn, U., et al) 239; exploration for 110, 308, 370; history and occurrence —Hochlichtbrechender Smaragd aus Sta. Terezinha de Goiâs, of, 236, from Kimberley, colours of, 372; nitrogen-defect Brasilien, 41 aggregation characteristics of, 446 —HENNj U., (a) Andesin-Mondstein aus Indien, (b) —emerald from deposits in Poona, Western Australia, 382 Schleifwürdige Korunde von Ngoronghoro, Tansania, Id., —emerald, synthetic: made from Pool emeralds, 41 41 —gemfields, 380 —HENN, U., Changierender Taaffeit aus Sri Lanka, 103 —gems around, 305, 439 —HENN, U., Ein Beitrag zur Unterscheidung natürlich —gem names, misuse of, 305 blauer und durch künstliche Bestrahlung blaugefärbter —geology of Coober Pedy precious stones field, 382 Topase anhand von Thermolumineszenzuntersuchung, 178 —iolite, aventurescent, from Mt. Philip, 305 —HENN, U., Ein ungewöhnlicher Granat aus Ostafrika, 103 —journey with colour, Lightning Ridge opal field, 379 —HENN, U., Farbloser, klar durchsichtiger, geschliffener —malachite from, 242 Sellait aus Brasilien, 103 JGemm., 1991,22 525

—HENN, U., Geschliffener, rosafarbener Hodgkinsonit aus by rotation, 353; faces and angles, selected, of, Franklin Furnace, New Jersey, USA, 369 346 —HENN, U., Künstliche gefärbte Quarze als Imitationen für —electron irradiated: absorption spectra, 34, 36; dichroism in, Smaragd, Rubin und Saphir, 369 36; mechanisms involved in creating colour centres in, 35; —HENN, U., Schleifwürdiger, transparenter blauer Saphir thermal treatment of, 33, 36 aus Kenia, 103 —green, from Australia, 440 —HENN, U., Untersuchung eines im Flussmittelverfahren —group, gemstones of, 372 hergestellten synthetischen roten Spinells aus der UdSSR, —growth structures in, 430, 431, 432 178 —imitation {see Synthetic and simulated gemstones) —HENN, U., BANK, F.H., PLATEN H.v., HOFMEISTER, —as an inclusion in emerald, 159 W., Leuchtendblaue Cufuhrende Turmaline aus Paraiba, —from Nigeria, 196: crystal morphology of, 431; geological Brasilien, 178 occurrences of, 197, 198; growth structures in, 430, 431, —HENN, U., LIND, T., Synthetische Smaragde aus 432 Australien (synthetische Tool emeralds'), 41 —from Pakistan, in Dusso, 378 —HENN, U., PETSCH, E., Spinelle aus dem Umba-Tal, —pink, differences from morganite due to differing crystal Tansania, 104 field symmetry ofMn3+ ions, 112 —HENN, U., PLATEN, H.v., Geschliffener, durchsichtiger, —red: from Wah Wah mountains, Utah, 378; fine crystals, 445 gelbbrauner Parisit aus Muzo, Kolumbien, 369 —spectra, infrared, of vanadium-bearing from Brazil, 218 —HENN, U., SCHMIDT, S.T., Hochlichtbrechender Rubin —synthetic {see Synthetic and simulated gemstones) aus Malawi, 104 —tourmaline inclusions in, 377 —PLATEN, H.v., AMARASINGHE, A.G.B., Saphirblauer, —from USA: in Utah, red beryl from Wah Wah mountains, durchsichtiger Sapphirin aus Sri Lanka, 104 378, 445 BANK-SCHERNER, M., {see Henn, U., et al.) —water in: 216; absorption bands in the infrared, 215; BARBOSA, J.E., {see Cozar, J.S., et al.) significance of in separating natural and synthetic, 215 BARKER, N.J., (^.Foster, G.V.) BEVINS, R.E., SHARPE, T., Welsh minerals, 379 BARNES, L.C., BECK, R.J., LEAMING S.F., TAN, L.-P., BIANCHI POTENZA, B., DE MICHELE, V., LIBORIO, World review of nephrite jade - geology, production and G., NANA, G.P., L'olivina délia Val Malenco (Sondrio) reserves, 439 come materiale di interesse gemmologico, 370 BARTOLI, F., BITTENCOURT, ROSA D., DOIRISSE, BIDEAUX, R.A., {see Anthony, J.W., et cd.) M., MEYER, R„ PHUJPPY, R., SAMAMA, J.-C, Role of BILLE, C, CHAPOULE, R., DORBES, J., SCHVOERER, aluminium in the structure of Brazilian opals, 369 M., Reconnaissance d'un diamant de synthèse De Beers Basalt: as a gem material, 180 parmi d'autres gemmes grâce a la cathodoluminescence, —in Nigeria: alkali, decomposed, mineralogy of, 198 104 —peridot grains in Hawaiian, 242 Biotite: associated with rose quartz, 277, 278, 280 —sapphire crystals in: morphology of, 472, 474; in Nigerian, BIRMINGHAM, J.C., Mourning jewellery, 104 198, 201 Biron synthetics {see Synthetic and simulated gemstones) —zircon crystals in Nigerian, 200, 201 Bismuth associated with rose quartz, 274 Bead buyers and parcel pickers filter set, 212 Bismuth germanium oxide {see Synthetic and simulated Beads: colour filter set for buyers of, evaluation of, 212 gemstones) —silica, from Cambay: drilling equipment ,91, 92; drillholes Bismutite associated with rose quartz, 274 of, origin of grooves in, 93, 95 BITTENCOURT, ROSA D., {see also Bartoli, F., et al.) —pearl, cultured, dyed pink, 107 —Les opales nobles du District de Pedro II dans l'Etat de —pearl, drill holes chipped, 107 Piaui - Région Nord-Est du Brésil, 370 Bead Society of Great Britain, 249 BLADH, K.W., {see Anthony, J.W., et al.) BEATTIE, R., {see also Brown, G., et cd.) BLANKENSHIP, D.T., Orange peel, 439 —Personalities behind the gem world: Kokichi Mikimoto —The sawing of jade, 439 1858-1956 [1954?], 104 —The toughness of nephrite, 370 BECK, R.J., {see cdso Barnes, L.C., et al.) BLEIKER, R., Die berühmte chilenische Lapis-Lazuli- —A new development in understanding: the prehistoric usage Lagerstätte bei Ovalle, Region Coquimbo, 370 of nephrite in New Zealand, 369 BOEHM, E., {see Koivula, J.I., et al.) —Jade of the Pacific, 439 Boehmite: Beetles, iridescent green, set in a diamond brooch, 107 —as an inclusion: in corundum, 114; in ruby, 88, 487, 488; in BENAVIDES-MUftOZ, M.E., {see Corona-Esquivel, R.) sapphire, 110,179 BENJAMIN, M., Imitation opalized shells, 305 BOGDANOVIC, K.I., Nephrite deposits in the Kuen-Lun BENNET, D., MASCETTI, D., Understanding jewellery, mountains, 439 182 Bone: carved, from India, 440 BENTE, K., THUM, R., WANNAMACHER, J., Colored —structural differences from elephant and vegetable ivories, pectolites, so-called 'Larimar' from Sierra de Baoruco, 105 Barahona Province, southern Dominican Republic, 369 BORELLI, A., A brief note on problematical yellow-brown BERK, M., New from New England, 104 diamond, 104 BERTONI, S., {see Rustioni, M.) BOSSHART, G., Emeralds from Colombia (Part 1), 355, Beryl: {see also Aquamarine, Emerald, Morganite) (Part 2), 409, (Part 3), 500 —associated with rose quartz, 274, 277, 278, 280, 282, 283, —II verde di Dresda, 439 284 —Les émeraudes de Colombie [1], 370, [2], 439 —from Brazil: from Minas Gérais, tourmaline inclusions in, Botswana: diamond production and prospecting in, 308 377; from Salininha,Bahia, Cr/V ratio in, 411; vanadium- Bow drill used in the Cambay bead industry: construction of, bearing, infrared spectrum of, 218; 91,92; diamond bits, single and double, 92, 93, 95; drilling —chatoyancy in, 395 patterns produced by, 93, 94, 95; drilling speeds of, 96; —colour filter test on yellow, 213 marking and perforation with, 91, 92, 93; silica powder —crystals: characteristic habit of, 349; cross-sections of, seen produced by, collection and uses of, 92, 95 526 JGemm., 1991,22

Bowenite: (see also Serpentine) —Cowell jade update, 235 —termed 'jade' in China, 110 — Dayboro variscite, 104 —neolithic carving of in China, 242 —Detecting dyed jadeite, 370 BOXER, J.L., (see Grice, J.D.) —Gemmological Study Club Lab Report, 305 BRACEWELL, H., (see also Brown, G., et al.) — Kauri gum revisited, 104 —Gems around Australia, 305, 439 —Kuri Bay cultured pearls, 235 —Wave Hill prehnite, 104 —Some Australian turquoise deposits, 440 Brazil: alexandrite from Hematita, 105 —Some rare ivories, 305 —amethyst from: growth structures in untreated, 480, in heat- —Synthetic quartz update, 235 treated, 481; in Maraba, 106; in Pau D'Arco, 106; in Rio —The appropriateness of GAA's gemmological nomenclature, Grande do Sul, 106 Presidential address, 305 —andalusite from new location at Maricota, 105 —Vulcanite or gutta-percha? That is the question, 292 —apatite, dark green, from Governador Valadares, Minas —BEATTIE, R., SNOW, J., Verneuil synthetic red spinel, 440 Gerais, 242 —BRACEWELL, H., Mt Philip aventurescent iolite, 305 —aquamarine from Jaqueto mine, Bahia, 447 —BRACEWELL, H., Yundamindera 'fire'opal, 105 —axinite from Bahia, 241 —CHAPMAN, J., Argyle champagne and cognac diamonds, —beryl: in Bahia, Cr/V ratios in, 411; in Minas Gérais, 440 tourmaline inclusions in colourless, 377 —KELLY, S.M.B., Knischka-created rubies, 178 —Brazilian Trio, 106 —KELLY, S.M.B., BEATTIE, R., BRACEWELL, H., —chrysoberyl crystals from Pancas, Espirito Santo, 242 Gemmological Study Club reports, 305, 440 —Chrysoprase: from Goiâs, bunsenite in, 443; fluorescent in —KELLY, S.M.B., BEATTIE, R., Gemmological Study Club UV, 308, 443 Lab reports, 440 —diamonds from: crystal forms of, history of working, 105; in —KELLY, S.M.B., SNEYD, R., Russian flux-grown synthetic Minas Gérais, diamond-bearing placers, 377 spinel, 440 —emerald from: chemistry, 376, occurrences in, 147, as raw —KELLY, S.M.B., SNOW, J., Russian hydrothermally-grown material for Pool synthetics, 41, thermal conductance, 234; emerald, 105 from Belmont, 376; from Capoeirana, gemmological —KELLY, S.M.B., SUTHERLAND, C, CALLAWAY, P., properties, inclusions, 106; from Carnaiba, Bahia, chemical Imitation chicken-blood stone, 440 analysis, 172, lattice parameters, 172, 173, 177, —LINTON, T., An inexpensive conversion unit, 440 occurrences in, 148; from Conquista (?), absorption —LINTON, T., Treasure Chest gem tester, 306 spectrum, 415; from Itabira, infrared spectra of, 218; from —SNOW, J., BRIGHTMAN, R., YAGG: a gemmological Nova Era, 109; in Riacho do Mamao, new discovery, 105; study club report (not indexed) 306 from Santa Teresifia de Goiâs, 41, 376, chemical analysis, —SNOW, J., Some observations on helenite, 105 171, high Cr content, 416, inclusions, 241, infrared spectra, —TOMBS, G., An introductory note on the manmade 173, 174, 175, 176, 218, lattice parameters, 172, 173, 177, products of Dominique Robert, 441 occurrence, 241, optical properties, 241, treated with Bruennerite as an inclusion in emerald, 157 Opticon, 110; from Socotô, inclusions in, 154, infrared Bruton, Mr E.M., address by, 312 spectra, 218, occurrences in, 148, physical properties, 154; BULGAK, L.V., (see Godovikov, A.A.) from Tauâ, infrared spectrum, 219 Bunsenite in Chrysoprase, 443 —lazulite, gem quality, from Bahia, 370 Burma: (see also Myanmar) —microcline, hyaline, from Minas Gérais, 370 —along Burma's jade trail, 444 —Minas Gerais: in Jequitinhonha Valley, crystallized rose —jade from: along the trail of, 444; auction in, 375; trouble at quartz occurrences, 280, 370; liddicoatite from, 239; the mines, 445; ureyite in jade-like material, 226 massive rose quartz locations in, 276 —Mogok: radioactivity in some minerals from, 422; spinel —opal: from Bahia, chatoyant, 236; from Piaui, 370, role of from, 108 aluminium in the structure of, 369 —ruby from: damaged by repair to setting, / 79; inclusions, 42; —rose quartz from: gemmological properties, 285, 286; interference figures in, 350; proton-induced X-ray emission geological occurrence of, 273, 274; locations of, analysis of, 446 crystallized, 280, 370, 376; massive, 275 —scapolite from: colour as a guide to composition of, 259, —sellaite from Brumado mine, Bahia, 103 260,262 —Serra de Jacobina, Bahia: geology of, 150, 151, 152; Campo —spinel from Mogok, 108 Formoso batholith in, 152, 153 —trouble at the mines, difficulties in working the jade, 445 —spodumene, lettuce-green, from Minas Gérais, 376 —ureyite, in jade-like material from, 226 —topaz from Padre Paradiso, Minas Gerais, spessartine —zircon from, 307 inclusions in, 366 BURNHAM, B.C., (see Anneis, A.E.) —tourmaline from: from Paraiba, blue and green, 110, 178, Burslem, Mr W.A., Obituary, 246 180, 238, 306, 308, 447, heat treatment of, 239, 306, BURT, D.M., Vector representation of tourmaline intensely coloured, from Salgadinho, 371, violet-blue from composition, 105 new mine at San Jose Baltalha, 179; from Minas Gérais, Burundi: sapphires found in, 180 multi-coloured crystals, 447, sceptre elbaite, 242 BUSHNELL, N., Diamonds - Australia's great treasure hunt, —triphylit« from Minas Gérais, 371 235 Brewster angle: of polarisation, 102; refractometer, 100, 102 BUZAS, Z., Interessante Einschlüsse in mexicanischem Opal, BRIDGES, CR., GRAZIANI, G., GÜBELIN, E., A Kenyan 105 gemstone of the feldspar family; further observations, 178 Bytownite: associated with ruby, 487; electron microprobe BRIGHTMAN, R., (see Brown, G., et al.) analysis, 492 Brilliance, dependence of on cut and critical angle, 101 BROWN, G., (see also Kelly, S.M.B., Linton, T., Phillips, G., Cailliaud, Frédéric, biography of, 115 and Snow, J.) CAIRNCROSS, B., The Messina mining district, South —A rare baler shell pearl, 439 Africa, 441 —Biron synthetic pink beryl, 305 Cairncross necklace, 6 JGemm., 1991,22 527

Calcite: associated with emerald, 238, 357 Chatham synthetics (see Synthetic and simulated gemstones) —cobaltian, from Mashamba West mine, Zaire, 374 Chatoyancy: apatite cat's-eye, greenish blue, 308 —as an inclusion: in emerald, 157, 421, 423; in ruby, 42 —andalusite cat's-eye, 237 —stained to imitate rhodochrosite, 308 —in chrysoberyl, 395, 306 CALLAWAY, P., (see Brown,G., et al.) —diopside cat's-eye, 309 CALVERT, J., The gold rocks of Great Britain, 244 —iolite cat's-eye: 239, 309, 395; parallel fibres in, pleochroism Cambodia: in, 396 —sapphire from: in alkali basalt, crystal morphology of, 472, —in opal: 309, 443; from Brazil, 236; in Idaho opal mounted 474; growth structures in, 474, 475; from Pailin, angled as composites, 443; from Mexico, black, 444; triplets, 444 growth structure in, 350 —scapolite cat's-eye from Burma, 261 CAMPBELL, I.C.C., A report on one of a number of —in strongly pleochroic gems, 395 emeralds from Madagascar, 441 —tanzanite cat's-eye: 309, 397; parallel channels in, —Doublets which simulate emerald, 235 pleochroism in, 397 —Fine quality large cut opal, 441 —tourmaline cat's-eye, red-blue, 444 —Visual structural differences between elephant ivory, bone —in zircon, heat-treated, 107 and vegetable ivory, 105 CHAUVET, M., Frédéric Cailliaud, 115 —KLEYENSTÜBER, A.S.E., An alexandrite of apparent Chelsea filter: identification with, 240; similarity to the Hematita origin, 105 Hanneman Aqua Filter, 212; transmission spectrum, 240, CAMPBELL, T.J., (see Roberts, W.L., et al.) 375 Canada: amethyst from Thunder Bay, Ontario, 114 Chicken-blood stone from China, 114, 307 —famous mineral localities of, 380 —imitation (see Synthetic and simulated gemstones) —gems and ornamental stones of, 378 CHIENG, TE-K'UN, Chinese jade exhibition, 370 —gormanite in quartz from the Yukon, 374 CHIHARA, K., (Jadeite in Guatemala), 370 —grossular garnet from the Jeffrey Mine, Quebec, 103 Chile: lapis lazuli from, 370 —kimberlite pipes in: exploration for, 110, 239; China: bowenite termed 'jade' in, 110 microdiamonds in, 239 —chicken-blood stone: 307; from Zhejiang Province and Inner Canary Islands: peridot from Lanzarote, 43 Mongolia, 114 CARLSSON, G., Radiamanter fran Australien, 236 —diamond from: cutting, 110; octahedron from Changma, CASSEDANNE, J.P., Découverte d'un nouveau gîte 231; prospecting for, 308; silicon carbide inclusion in, 374 d'émeraude, 105 —gemmological teaching in, 224, 229, 230, 231 —Diamonds in Brazil, 105 —gems from: 42; deposits in Inner Mongolia, 309 —Maricota, un nouveau gisement d'andalousite (Minas —Geological Museum, Beijing, diamond octahedron in, 231 Gérais, Brésil), 105 —jade: carvers and their customers in Ming China, 441; —Un nouveau matériau gemme: le quartzite à lazulite (Bahia - exhibition of, 370; flowers in, 376; in Khotan, 378; jade Brésil), 370 mining in, 446 (2); neolithic carving in, 242; nephrite —Un nouvel indice de microcline gemme à Minas Gérais, 370 deposits in the Kuen-Lun mountains, 242 —ALVES, J., Crystallized rose quartz from Alto da Pitora, —nephrite deposits in the Kuen-Lun mountains, 439 Minas Gérais, Brazil, —pearl farming at Yangxin, Hubei Province, 11 —LEDOUX, L.A., Une curieuse opale chatoyante, 236 —realgar, gem quality, from Shimen, Hunan Province, 242 —RODITI, M., Crystallized and massive rose quartz deposits —sand-buried ruins of Khotan, 446 in Brazil, 273 —snuff bottles from, 111 Cassiterite: associated with Central Nigerian granites, 196 —University of Geosciences, Wuhan: gemmological teaching —associated with rose quartz, 282, 283, 284 at, 228, 229, 230 CASTIGLIONI, A., (see Grubessi, O., et al.) —visits to High Tartary, Tarkand and Kashgar, 446 Catalonia: (see also Spain) gemmological teaching in, 337 Chlorite: associated with rose quartz, 284 Cathodoluminescence: in alpha-quartz, factors affecting short­ —as an inclusion in emerald, 156 lived blue, 375 —electron microprobe analysis of, 170 —microspectrophotometry of, to distinguish between natural Chromite: as an inclusion in emerald, 156, 159, 501 and synthetic stones, 112 Chrysoberyl: chatoyancy in, 395; in carved horse head, 306 —a new technology of the 1980s, 237 —crystals from Espirito Santo, Brazil, 242 —in rubies, 43 —star, from Sri Lanka, 180 —in sapphires, yellow, 375 Chrysoprase: from Marlborough, Australia, 444 —in synthetic diamond: De Beers, 104; Maltese Cross type, —from Brazil: nickel in the form of bunsenite in, 433; zoned 237 and fluorescent in UV, 308, 443 Cavenago Bignami Moneta, Senora S., Obituary, 184 —mineralogy and properties of, 112 Central America: (see also Guatemala, Honduras, Mexico and —from Poland: cause of colour in, 43; in Silesia, Szklary, Nicaragua) jade from, 107 classic location of, 377 Ceres Diamond Probe, 375 —from Tanzania: microscopic structure of, geological origin Ceylon (see Sri Lanka) of, 373 Chalcedony: (see also Agate, Chrysoprase and Mtorolite) CIBJO regulations on nomenclature of Pool synthetic —adularescent violet-blue from Mojave desert, 180 emeralds, 41 —artificially induced dendrites in, 460 Cinnabar inclusions in chicken-blood stone, 307 —dendritic, from Australia, 305 Citrine: associated with rose quartz, 274 —fossil pine cone preserved in, from Patagonia, 308 —colour filter test on, 213 Chalcocite: associated with rose quartz, 274 —conversion from amethyst by heat, 42 Chalcopyrite: associated with rose quartz, 274 —crystal morphology, 481 —as an inclusion in emerald, 241 —growth structures in, 481 CHANCEREL, C, Bloody opals...! 441 —synthetic (see Synthetic and simulated gemstones) CHAPMAN, J., (see Brown, G., et al.) Claringbull, Sir Frank, Obituary, 311, 330 CHAPOULE, R., (see Bille, C, et al.) CLIFFORD, P., Gem fire, 236 528 JGemm., 1991,22

CLUNAS, C.j Jade carvers and their customers in Ming Coral: 241 China, 441 —black, in the Mexican Caribbean, 444 Codazzite associated with emerald, 238 —species depicted on postage stamps, 498, 499 COENRAADS, R.R., Key areas for alluvial diamond and Cordierite (see also Iolite) sapphire exploration in the New England gem fields, New —from south Norway, 372 South Wales,Australia, 370 CORONA-ESQUIVEL, R., BENAVIDES-MllROZ, M.E., —SUTHERLAND, F.L., KINNEY, P.D., The origin of Excursion de la Sociedad Mexicana de Minerologia a las sapphires: U-Pb dating of zircon inclusions sheds new light, minas de öpalo del Estado de Querétaro, 371 236 Corundum (see also Ruby and Sapphire): 310 Colclough, Mr A.C., Obituary, 311 —in alkali basalts, 236 Cole, Mr K.C., Obituary, 45 —apatite inclusions in, 114 Collinsite: associated with rose quartz, 282 —boehmite inclusions in, 114 Colombia: —crystals: characteristic habit of, 349, 467; cross-sections of, —Colombian emerald belt, geographical and geological setting seen by rotation, 353; faces and angles, selected, of, 345; of, 238, 356 growth of linked with alkali basalt magma generation —emerald from: absorption spectra, 411, 412, 413, 414, 416, processes, 236 418, 439; chemistry, 410, 411; crystal morphology, 410; —crystal inclusions, flat, rounded, doubly refractive, in, 87 gemmological review of, 239, 439; genesis, hypotheses of, —from East Africa: in the Umba region, inclusions in, 114 238, 357, 370; geographical locations of, 356; geological —elements in, detection of by microspectrofluorescence, 106 occurrence, 238, 357; growth structures, 423, 424, 425, —geuda : anomalous behaviour during heat treatment, 405; 439; inclusions, 418, 419, 420, 421, 422, 423, 439; infrared colour, cause of, influence of minor trace impurities on, spectra , 218, 219; mining, 113, 181, 356, 359, 370; as raw 179, 406; electron microprobe analysis, 405, 406; as raw material for Pool synthetic emerald, 41; thermal material for heat treatment, 179 conductance, 234; typomorphic features of, 238 ; from —graphite inclusions in, 114 Chivor, infrared spectrum, 218; from Ganchalâ, —inclusions in, 86, 87, 88, 114 distinguishing features, 416, 423; from Muzo, chemical —from Malawi: orange and red, 108; absorption spectra, 83, analysis, 171, infrared spectra, 173, 174, 175, 176, thermal 84; chemical analysis of trace elements, 84, 85; inclusions, conductance, 234 86, 87, 88, variations in colour and physical properties —mining problems in Muzo, 42 related to trace element concentrations, 84, 89 —new aspects of emerald workings in, 181 —orange, from Malawi, 83, 108 —parisite: from Muzo(?), absorption spectrum, 422; from —padparadscha (see also Orange corundum above and Muzo, transparent, faceted, 369 Sapphire): what is meant by this term?, 442 —sapphire from, 239 —red: from Malawi; 83, 108; from Tanzania, 41 Colorimeter, spinning disc tristimulus, 338 —rutile inclusions in, 87, 114 Colour: in agates, Scottish, 237 —spectra, fluorescence, 106 —in beryl, produced by electron irradiation, 33 —from Sri Lanka: clear and opaque as raw material for heat —centres, creation of, in electron irradiated beryl, 35 treatment, 179; geuda, änomolous behaviour of during heat —change: in fluorite, 376; in taaffeite, 103 treatment, 405 —in Chrysoprase, cause of, 43 —from Tanzania, 41 —CIE Tristimulus System for measurement of, 339 —in Gulf of Thailand, undersea propspecting for, 110 —in diamonds, 439 —treated: clear and opaque as raw material for heating, 179; —in emerald: from Colombia, causes of, 411, saturation of, diffusion-treated, 442; geuda, heated, 405 411, zoning in, 423, 425 Council Meeting, 117 —filter set for bead buyers and parcel pickers, evaluation of, Council of Management Meetings: 247, 320, 384, 449, 512 212 COUPER, A. G., Colour as a guide to the composition of —in hackmannite, changed by UV, 42 scapolite from Burma, 259 —measurement of: with CIE Tristimulus System, 339; with COUSENS, D.R., (see Griffin, W.L.,er al) microscope, 376; spinning disc tristimulus colorimeter for, COUTO, P.A., (see Schwartz, D., et al) 338 Covellite: associated with rose quartz, 274 —pleochroic: in andalusite, 106; in iolite cat's-eye, 396; in COZAR, J.S., Determination de rasgos de tratamiento, en Lechleitner synthetic emerald, 27; in sapphire, 397; in topacios azules irradiados, por espectroscopia gamma de tanzanite cat's-eye, 398 alta resolution, 106, 371 —in ruby, intensity related to trace element concentration, 84, —SARMIENTO, L., BARBOSA, J.E., Trifilita gems, 371 89 CRAM, L., Journey with colour, 379 —in sapphire from Kashmir, 68 Critical angle: determining cut and brilliance, 101; Letters to —in scapolite from Burma, a guide to the composition of, 259, the Editor, 321, 322 260, 263 —of diamond, 99 —in sodalite group, 372 —of quartz, 99 —in tourmaline: blue and green from Paraiba, due to copper —total internal reflection, relationship to, 101 and manganese, 238; role of natural radiation in, 240 CROWNINGSHIELD, R, (see also Fryer, C.W., et al) —zoning: in emerald from Socotö, 161, 162; in Lechleitner —address by, 46 synthetic emerald, 22, 23, related to trace element —Grading the Hope diamond, 41, 106 distribution, 22, 28; in treated diamonds, 42, 306, 441 Crown jewels of France, 115 Columbite associated with rose quartz, 277, 278 Crystals: 183 Computer software (see Gem identification) —beryl: characteristic habit, 349; faces and angles in, 345; Computerized information services, 111 cross-sections of, seen by rotation, 353 CONKLIN, L.H., The Harvard diamond crystal, 371 —corundum: characteristic habit, 348, 467; faces and angles CONNER, L., (see Fritsch, E, et al.) . in, 345; cross-sections of, seen by rotation, 353 Conoscope (see Instruments) —crystallography, introduction to, 380 COOK, R.B., (see White, J.S.,) —emerald, Colombian, famous specimens of, 410 JGemm., 1991,22 529

—faces and characteristic angles in optical uniaxial, means for —from China: from Changma, octahedron from, 231; determination of, 347, 349, 350, 351, 352, 354 exploration for, 308; silicon carbide inclusions in, 374 —gem, depicted on postage stamps, 498, 499 —clarity analysis machine, computerized, 239 —gems and crystals, how they can transform your life, 381 —cleavage: in laser-drilled diamonds, 306; internal, covered —habit of Alpine quartz, 237 with trigons, 237 —hexagonal or trigonal, cross-section showing determination —coloured: Australian, 372, champagne and cognac from of internal structural features in, 347 Argyle, 440; in bluish-green, 306; in naturally irradiated, 42; —morphological differences between natural and synthetic: of orchid of the mineral kingdom, 439; rare purple, 306; amethyst, 479, 481, 482; of citrine, 482; of emerald, 431; of yellow, probably natural, resembling Sumitomo synthetics, ruby, 476, 479; of sapphire, 474, 476 441; zoning in artificially irradiated and annealed stones, 42, —precious crystals, 382 441 —quartz: characteristic habit, 349; cross-sections of, seen by —colourless: N3 centres, as a characteristic of natural origin, rotation, 353; faces and angles in, 346; habit of Alpine, 237; evidence of in optical absorption spectra, 142, 145; phantom in, 106 —critical angle: 97; increased by grease on pavilion, 99; —phantom, in quartz, 106 importance of in polishing, 101 —sapphire, multi-zoned yellow, 42 —crystals, gems and associated activities depicted on postage —scapolite, forms and surface sculpture of, 113 stamps, 498, 499 —sceptre amethyst, 110, 239 —cutting: in China, methods, 110; in Mauritius, expansion of, —spinel: surface etch features on, 303 180 —spinel, synthetic: surface growth features of, 302, 303 —cuts: brilliant, Tolkowsky-type, calculations of approximate —structural properties in uniaxial, microscopic determination weight and correct proportions of, 235; lozenge, engraved of, 344 and painted, 107; new, 241; 'Old Mine', with concave table —structure of, influence of inclusions on, 106 facet, 107 —symmetry, non-cubic, of grossular garnet from the Jeffrey —diamond ring, the: business, politics and precious stones in Mine, 103 South Africa, 381 —tsavorite, euhedral crystals of, 307 —'diamond softening', misunderstanding of, 399 —zircon, 468 —drill used in Cambay bead industry, 91 Cuprite from Mashamba West mine, Zaire, 374 —etched by heat, 305 CURRAN, R.T., A Hamlin Mount Mica tourmaline, 371 —exploration and prospecting: in Angola, 308; in Australia, Cuts: brilliance in, origin of, 101; Letters to the Editor, 321, 110, 239 (2), 308, 370; in Botswana, 308; in Canada, 110, 322 239; in China, 308; in Guyana, 444; in Tanzania, 308 —brilliant, Tolkowsky-type, calculations of approximate —famous: Agra, 103; Dresden Green, 439, 443 ; Harvard, 371; weight and correct proportions, 235 Hope, 41, 106; Taylor-Burton, 235 —facet angles, nomographs for evaluation of, 373 —formation of, new environment for, 377 —incidence-radiation relations between incident rays through —garnet, colour-change, inclusion in, 179 the pavilion in, 373 —Gem Diamond Pen, 375 —new, mainly for diamonds, 241 —grading the Hope Diamond, 41, 106 —Old Mine, with concave table facet, 107 —graphite inclusions in, 306 —scintillation by the incident rays through the pavilion of, 373 —green, irradiated, 179 Cyrilovite, associated with rose quartz, 283 —from Guinea: geology and evaluation of diamond deposits in, 113; production, 378 DABDOUB, T., Opal report from Honduras 'The fire still —as an inclusion: in garnet and zircon, 377 burns', 379 —inclusions in, 179, 374 Danburite: distinction of from topaz by single-crystal X-ray —from Indonesia: in Kalimantan, nitrogen-defect aggregation diffractometer, 112 characteristics of, 446 DAWIDOWICZ, T., L'influence des inclusions sur la —irradiated (see Treated diamonds below) structure cristalline, 106 —low pressure growth of, (see also Synthetic and simulated De Beers synthetics (see Synthetic and simulated gemstones) gemstones) 236 DE MICHELE, V., (see also Bianchi Potenza, B., et al.) —from Myanmar, 307 —Kamienie szachetne i ozdobne wloch, 371 —nitrogen in: nitrogen-defect aggregation characteristics in, DERJAGUIN, B.V., FEDOSEEV, D.V., Low pressure 446; N3 centres, as a characteristic of natural origin, 142, diamond growth, 236 evidence of in optical absorption spectra, 142, 145 Diamond: —from Namibia: mining in, 237 —absorption spectra (see spectra, absorption below) —octahedron with etched channels, 306 —almandine-pyrope inclusion in, 179 —optical properties, significant phenomena concerning, 237 —from Australia: from Argyle, champagne and cognac —'paper-worn', 107 colours, 440, characteristics and mining, 446; exploration —passage of light through pavilion, nomographs showing, 373 for, 180\ 235, 239; history and occurrence of, 236; from —Presidium DiaMeter - System Berger, 443, 444 Kimberley, 372; nitrogen-defect aggregation in, 446 —price of brilliant-cut, abacus for determining, 369 —bi-colour yellow and white, fluorescence and —from primitive meteorites, 42 phosphorescence of, 179 —problematical yellow-brown, 104 —black: determination of 'Type' in, Letter to the Editor, 120; —reflectivity of, identification by, 97 graphite inclusions causing colour and electro- —scintillation elucidated by nomograph, 373 conductivity in, 306; an investigation of, 442 —shattered during minor repair-cutting, 237 —in bow-drill bits, fragments of, 92, 93, 94 —silicon carbide inclusion in, 374 —from Brazil: history of working, occurrences, typical crystal —sorting made easy, 114 forms, 105; in Minas Gérais, diamond-bearing placers, 377 —from South Africa: mining on the west coast, 180; the —computerized clarity analysis machine, 239 diamond ring, history and production of diamonds, 381 —from Canada: microdiamond in kimberlite, 239 —spectra, absorption: of colourless natural, at room —Ceres Diamond Probe, 375 temperature, 143, 144; of Dresden Green 443 530 JGemm., 1991,22

—Sumitomo (see Synthetic and simulated gemstones) Ekanite: star, 239 —synthetic (see Synthetic and simulated gemstones) Elbaite (see Tourmaline) —treated: colour zoning in artificially irradiated and annealed Electron irradiation of beryl, 33 stones; 42; filled, identification of, 43, 240, effect on grading Electron microprobe analysis, impact of on gemmology, 237 of, 239, new flash colours seen in, 239; fillers, new, 237; Electron microprobe data: glass filler, removal of, 180; irradiated blue octahedron, 179; —of amphibole rock, black, resembling jadeite, 133 irradiated green stone, radioactive, 179; laser-drilled, —of chlorite, 170 showing cleavage and branched drill-holes, 306 —of corundum, geuda, 405, 406 —trigons on an internal cleavage, 237 —of emerald: from Austria, Habachtal, 171; from Brazil, —total internal reflection in a polished gem, 101 Santa Teresifta, 171, Socotö, 154, of inclusions in, 156, —from USA: in Murfreesboro, south-west Arkansas, 374; 157; from Colombia, Ganchalâ, 416, Muzo, 171; from recent discoveries in Trinity County, California, 309 Egypt, in Djebel Zabarah, 171; from USSR, 171; from —from USSR: new find near Archangelsk, 308 Zimbabwe, 270 DIEHL, R., MENG, K.H., Ein gravierter Kashmir-saphir, —of Lechleitner synthetic emerald, 23, 24 371 —of phlogopite, 170 DIELLA, V., (see Sosso, F., et al.) —of plagioclase, 170 DIETRICH, R.V., SKINNER, B.J., Gems, granites and —of sapphirine, 138 gravels: knowing and using rocks and minerals, 380 —of ruby: 491, 492; of minerals associated with, 492 Di-iodomethane and all that, Letter to the Editor, 387 Electron-spin resonance, impact of on gemmology, 237 Diopside: chatoyancy in, 309, 395 Emerald: 242 —gem-grade chromian, from Japan, 375 —absorption spectra (see Spectra, absorption below) —green from Pakistan, 447 —actinolite/tremolite inclusions in, 156, 158, 268, 271, 272; —green transparent from USA, 376 microprobe analysis of, 156 —as an inclusion in olivine, 370 —from Afghanistan: from Panjsher Valley, absorption in UV, Dipyre (see Scapolite) 418, absorption spectrum in visible light, 417, 501; DIRLAM, D.M., (see Goebel, M. and Shigley, J.A., et al.) typomorphic features of, 238 DOIRISSE, M., (see Bartoli, F., et al.) —albite inclusions in, 421, 423, 501 Dolomite: associated with emerald, 357 —allanite inclusions in, 157, 158; microprobe analysis of, 156 —as an inclusion in emerald, 157, 423 —apatite inclusions in, 157, 161; microprobe analysis of, 156 DOMENECH, M.V., (see also Solans, J.) —from Australia: in Poona, WA, 382 —SOLANS, J., Estructura cristalina, composicion quimica y —from Austria: from Habachtal, chemistry of, 171, 172, propriedades fisicas de las gemas. 1 Densidad, 236 lattice parameters of, 172, 173, 174; mineralization during Domincan Republic: regional metamorphism, 238; in Untersulzbachtal, —amber from: containing fossil mushroom, 308; snail shells discovery of, 372 in, 443 —from Brazil: chemistry, 376, thermal conductance, 234; —pectolite from: blue, 242; characteristics and mining history, from Belmont mine, 376; from Capoeirana, gemmological 372; geological occurrence, 369 properties, inclusions, 106; from Carnaiba, 148, annual DORBES, J., (see Bille, C, et al.) output, 149, chemistry of, 172, lattice parameters of, 172, DORDA, J., (see Karwowski, L.) 173, 177, occurrences in, 147; in Conquista, absorption DOWNING, P.B., Opal adventures, 244 spectrum, 415; in Itabira, infrared spectrum, 218; from Dresden Green diamond, 439, 443 Nova Era, 109; from Riacho do Mamao, gemmological DUBOIS-FOURNIER, j., LENAIN, B., LE MAGUER, D., properties, inclusions, new discovery of, 105; from Santa La microspectrofluorescence et ses applications en Teresifta, 41, 376, chemistry of, 171,172, high Cr content, gemmologie, 106 416, lattice parameters of, 172, 173, 177, inclusions, 241, DUBOWSKI, E.A., (see Flint, DJ., et al.) infrared spectra, 174, 175, 176, 218, occurrence, 241, DUNHAM, K.C., Geology of the northern Pennine orefield. optical data, 241, treated with Opticon, 110; from Socotô, Vol 1. Tyne to Stainmore, 380 annual output, 149, geology of region, 150, 151, 152, 153, DUTROW, B.L., (see Dyar, M.D., et al.) 154, growth phenomena in, 159, 160, 162, inclusions, 154, DYAR, M.D., PERRY,C.L., REBBERT, CR., DUTROW, 155, 156, 157, 158, 159, 161, 162, infrared spectrum, 218, B.L., HOLDAWAY, M.J., LANG, H.M., Mossbauer microprobe analysis, 154, mining methods, 149, 150, spectroscopy of synthetic and naturally occurring optical properties, 154; from Tauâ, infrared spectrum, 219 staurolite, 441 —bruennerite inclusions in, microprobe analysis of, 157 —calcite inclusions in, 157, 421, 423; microprobe analysis of, EADIE, J., Gemmological visual aids, 207 157 —Paper gems, 498 —carbonaceous shale inclusions in, 421, 423 East Africa (see also Kenya, Malawi and Tanzania): —carbonate inclusions in (see also Breunnerite inclusions, —corundum from the Umba region, inclusions in, 114 Calcite inclusions above and Dolomite inclusions below), —garnet, unusual orange-brown, from, 103 241, 421 —ruby production potential of, 484 —cat's-eye, 410 Eaton, Mrs A., Obituary, 116 —chalcopyrite inclusions in, 241 EDIRIWEERA, R.N., (see Perera, S.Z., et al.) —chlorite inclusions in, 156 Egypt: —chromite inclusions in, 159, 501; microprobe analysis of, —emeralds from: from Djebel Zabarah, 164, 372; 156 gemmological properties, 170 —from Colombia: absorption spectra, 411, 412, 413, 414, —Pharaoh's forgotten emerald mines in: 164, 372; Castiglioni 416, 418, 439, chemical composition, chromophores and expedition to, 166; Djebel Zabarah, mines of, 168, 169, trace elements, 410, 411, colour, stability of, 501, crystal 170; emeralds from, 170; previous expeditions to, 164,165; morphology, 410, damage to a set stone, 501, 502, density, Sikeit, ancient city of mines at, 166, 167, 169 418, 419, distinction from natural and simulated emeralds, EIDT, T., (see Schwartz, D., et al.) 501, distinction from synthetics, 502, fluorescence, in UV Eickhorst Thermolyzer, 374 and visible light, 418, 421, gemmological review of, 239, JGemm., 1991,22 531

genesis, hypotheses of, 357, 370, geographical locations, —from Pakistan, 244: high refractive index and density values, 356, geological occurrence, 238, 357, growth structures, 501, inclusions, 501, typomorphic features of, 238; in 423, 424, 425, 428, 429, 430, 439, inclusions, 418, 419, Mingora, chemistry of, 172, lattice parameters of, 172, 173, 420, 421, 423, 439, 501, infrared spectra, 218, 219, 177; in Swat Valley, high Cr content, 416, thermal microprobe data, 416, minerals associated with, 238, 357, conductance, 234 mining, 181, 356, 359 370, notable specimens, 356, 410, —parisite inclusions in, 421, 423 optical data, 418, 419, 439, thermal conductance, 234, —pendandite inclusions in, 241 treatments, 501, 502, typomorphic features of, 238; from —phlogopite inclusions in, 441 Chivor, infrared spectrum, 218; from Ganchalâ, —pyrite inclusions in, 159, 241, 421, 423, 501 distinguishing features, 416, 423; from Muzo, chemistry, —quartz inclusions in, 157, 161, 421, 423 171, 172, infrared spectroscopy of, 173, 174, 175, 176, —rutile inclusions in, 241 lattice parameters, 172, 173, 177, mining problems, 42, —from South Africa: in Leysdorp, mineralization during thermal conductance, 234 regional metamorphism, 238 —colour filter tests on, 212, 213 —from South America: in Cobra Aline, thermal conductance, —colour zoning in Colombian, 423, 425 234 —damage to: by heating, 501; in a setting 501, 502; —from Spanish galleon Nuestra Senora de Atocha, treasure —definition of, based on Cr content, 502 of, 180 —dolomite inclusions in, 157, 423; microprobe analysis of, —spectra, absorption: of Afghan, 417; of Brazilian, 415; of 157 Colombian, 411, 412, 413, 414, 416; of Madagascan, 441; —doublets of, 235 in the UV, use in disinguishing natural from low-iron —from Egypt: from Djebel Zabarah, 164, 372; electron synthetics, 418; in Zimbabwean, 270 microprobe analysis of, 171;gemmological characteristics —spectrometry, atomic absorption, of, 270 of, 170; infrared spectroscopy of, 173, 174, 175, 176; —spectrometry, inductively coupled flame plasma, of, 270 lattice parameters, 172, 173, 177 —spectroscopy, infrared: classification of natural and —electron microprobe analyses, 154,171, 270, 416 synthetic, 220; distinction between natural and synthetic, —emerald/beryl inclusions in, 159 215, 217, 219, 221; spectra, 174, 175, 176, 218, 219, 221 —famous crystals, 410 —from Sri Lanka, poor quality, 180 —feldspar inclusions in, microprobe analysis of, 157 —synthetic emerald (see Synthetic and simulated gemstones) —filled fractures in, 237 —talc inclusions in, 156, 241, 501 —fluid inclusions in, 418, 419, 420 —from Tanzania: from Lake Manyara, infrared spectra, 221 —genesis of: Austrian, 238; Colombian, 238, 357 —thermal conductance of natural and synthetic, 233, 234 —geological occurrence: in Austria, 238; in Brazil, Socotô, —three-phase inclusions in, 418, 419, 420 150, 151; in Colombia, 238, 357; in Zimbabwe, 264 —tourmaline inclusions in: 157, 159; microprobe analysis of, —gersdorfifite inclusions in, 501 157 —goethite inclusions in, 159, 161, 423, 441 —trapiche, 410, 423 —growth structures: as an aid to distinguish between natural —treatments of (see Treated stones) and synthetic stones, 427, 431, 434, 438; in Colombian, —two-phase inclusions in, 423 423, 424, 425, 428, 429, 431; in Socoto, 159, 160, 161, —typomorphic features of, from various deposits, 238 162; measurement of angle formed by two sets of growth —from USSR: typomorphic features of, 238; from the Urals, planes, 351; in Nigerian, 430, 431, 432 chemistry of, 171, 172, lattice parameters, 172, 173, 177, —hematite inclusions in: 501; alteration to goethite, limonite thermal conductance, 234 or lepidocrocite, 159, 161, 241, 441 —from Zambia: infrared spectrum, 218; mines in, 309; in —ilmenite inclusions in, 241 Morrua, chemistry of, 172, lattice parameters, 172, 173, —imitation (see Synthetic and simulated gemstones) 177; —inclusions in, 106, 154, 155, 156, 157, 158, 159, 161, 162, —from Zimbabwe: geology of, 264, 265, 266, occurrences, 418,419,420,421, 423,441 266, 267, optical data, 271; from Machingwe, chemical —from India: thermal conductance, 234 analysis, 270, gemmological properties, 270, geology, 267, —from Italy: from Val Vigezzo, chemistry of, 172, lattice 268, inclusions, 268, 271, 272, infrared spectrum, 218, new parameters, 172, 173, 177 discovery in, 264, optical data, 271, photomicrographs of in —lepidocrocite inclusions in, 159, 161 host rocks, 268, production potential , 268; from —limonite inclusions in, 159, 161, 441 Sandawana, chemical analysis, 270, high Cr content, 416, —from Madagascar: absorption spectrum, gemmological similarity to Machingwe emeralds, 271 properties, inclusions, 441 Emeraldolite (see Synthetic and simulated gemstones) —magnetite inclusions in, 501 Endoscope, use in pearl identification, 10, 331 —mica inclusions in: 155, 156, 158, 161, 241, 271, 272; Eosphorite: associated with rose quartz, 282 microprobe analysis of, 156 Epidote: gem crystals from Val Punteglias, Switzerland, 113 —microprobe analysis: of Ganchalâ, 416; of Machingwe, 270; EPSTEIN, D.S., Brazilian trio, 106 of Socoto, 154 —The Capoeirana emerald deposit near Nova Era, Minas —mineralization during regional metamorphism, 238 Gerais, Brazil, 106 —mining: in Colombia, 181, 356, 359, 370 ERCIT, T.S., (see Groat, L.A., et al.) —molybdenite inclusions in, 159, 161, 501 Euclase: associated with emerald, 357 —natural and synthetic, distinguished by growth structures, —from Zimbabwe, 108 427,431,434,438 EVANS, D.J.F., (see Frank, F.C., et al.) —from Nigeria: crystal morphology, 431; growth structures, EVEN-ZOHAR, C, Namibia: walking on diamonds, 237 430, 431, 432; in Jos, absorption in the UV, 418, infrared Examinations: spectrum, 218, low Mg, Na content, 411; measurement of —Gem Diamond Examination: 1989, 46; 1990, 314; 1991, angle between two sets of parallel growth planes in, 351 506 —oiling of (see Treated stones) —Examinations in Gemmology: 1989, 48; corrigendum, 119; —optical data: for Colombian, 419; for Zimbabwean, 271 1990,315; 1991,506 —orthite inclusions in (see Allanite inclusions above) Executive Meetings, 53, 185 532 JGemm., 1991,22

Exhibitions: pavilions, 42 —Cheapside Hoard, new display at the Museum of London, —SHIGLEY, J.E., ROSSMAN, G.R., MERCER, M.E., 249 MUHLMEISTER, S.M., MOON, M., Gem quality —Gemstones, Geological Museum, London: proposed new cuprian-elbaite tourmalines from Säo Jose da Batalha, exhibition and re-location of, 130 Paraiba, Brazil, 306 —Mineral Gallery, The Natural History Museum, London: Frondelite associated with rose quartz, 283 proposed new exhibition and re-location of, 130 FRYER, C.W., {see Koivula, J.I., et al.) —Treasures and Trinkets, Museum of London, 249 —CROWNINGSHIELD, R., HURWIT, K.N., KANE, R.E., Exploration for gemstones, isotopes used in, 114 HARGETT, D., Gem Trade Lab notes, 42, 106, 179, 237, Export of natural heritiage specimens: Letter to the Editor, 306, 441 186 Fuchsite: electron microprobe analysis, 492 Extraordinary General Meeting, 247 —as an inclusion in ruby, 491 FUERTES MARCUELLO, J., GARCIA GUINEA, J., FARN, A. E., Pocahontas, 331 Caracterizacion mineralogica e historica del larimar de —Letter to the Editor, 451 Barahona, 372 FAULKNER, M.J., SHIGLEY, J.E., Zircon from the Harts FUJINUKI, T., {see Wade, K.) Range, Northern Territory, Australia, 178 FUKUNAGA, O., {see Miyamoto, M., et al.) FEDERMAN, D., Modern jeweler's consumer guide to gemstones, 244 GAA's gemmological nomenclature, appropriateness of, 1990 FEDOSEEV, D.V., (see Derjaguin, B.V.) Presidential address, 305 Feldspar {see also K-feldspar and Plagioclase): GABRIEL, W., {see Weibel, M., et al.) —gem and ornamental varieties, 107, 111 Gahnite {see also Spinel): from Central Nigeria, 202 —as an inclusion in emerald, 157 GAMINI ZOYSA, E., {see Harding, R.R.) —from Kenya, 178 GANGEWERE, R.J., {see Souza, R.A., et al.) FERREIRA, J.A.M., KARFUNKEL, J., SILVA, L.T., GARCIA GUINEA, J., {see Fuertes Marcuello, J.) Turmaline mit ungewöhnlich intensiven Farben von GARCÎA GIMÉNEZ, R., LEGUEY, S., Saphirs et rubis de Salgadinho, Paraiba, Brasilien, 371 Tanzanie, 237 FIELD, R., Colour in Scottish agates, 237 Garnet: {see also Almandine garnet, Grossular garnet, Pyrope- Figure-O-Scope, 113 almandine, Pyrope garnet, Rhodolite, Tsavorite) Finland: beryl from, 239 —associated with rose quartz, 274 —ruby from Kittilae, Lapland, 109 —diamond inclusions in, 377 FLAMINI, A., {see Attanasio. D., et al.) —unusual orange-brown, from East Africa, 103 FLEISCHER, M., MANDARINO, J.A., Glossary of mineral GAUTHIER, G.J., {see Lhoest, J.J., et al.) species, 448 GAUTHIER, J.-P., LASNIER, B., La perle noire obtenue par FLINT, DJ., DUBOWSKI, E.A., OLLIVER, J.G., Latest traitement à l'argent, 237 report on Cowell jade, 371 GAUTRON, L., Alpine quartz, 237 Fluorescence in variscite, 104 Gemdata gem identification programme: evaluation of, 111; Fluorite: 447 modified version available, 119 —associated with emerald, 238, 357 Gem deposits, world map of, 119 —colour-change from Schwarzwald, Germany, 376 Gem Diamond Pen, 375 —colour filter test on yellow, 213 Gemeter, 97, 98 —green, imitating emerald, 309 Gemexpert, 98, 99 —world occurrences, 378 Gemfields, 380 FOSTER, G.V., BARKER, N.J., Suggestions for Gem identification: photographing jewellery, 287 —best light for ?, 241 Forsterite {see also Olivine and Peridot): —computer software for: Gemdata gem identification —as an inclusion in pyrope, 374 programme, evaluation of, 111; gem identification software, France: azurite from Chessy, 441 GIS, preliminary assessment of, 180, Letter, 309 —crown jewels of, 115 —gem testing, 243 —ruby from Chantel, 109 —Stellenbosch gern index, 245 FRANK, F.C., LANG, A.R., EVANS, D J.F., ROONEY, M- Gem localities of the 1980s. 241 L. T., SPEAR, P.M., WELBOURN, CM., Orientation- Gemmological Association of Great Britain: correspondence dependent nitrogen incorporation on vicinals on courses, translation of into Chinese, 231, 232; merger with synthetic diamond cube growth surfaces, 237 the Gem Testing Laboratory of GB, 194 FRAZIER, S., FRAZIER, A., Inter-Agate, 106 Gemmological Conference, XXII International, Italy, 38, 181 —Phantoms, 106 Gemmological teaching aids, visual: Fresnel equation, simplified, 97 —colorimeter, spinning disc tristimulus: colour measurement FREY, R., Jade in Korea, 371 with, 338, 339 —Satellite scans: technical notes and gazetteer, 441 —to demonstrate formation of conoscopic figures, 338 FRIESE, B., Morphologie und Entstehung der Sternsaphire —goniometer, single circle: demonstration of optics with, 337, aus Zaire, 372 338 FRITSCH, E., {see also Kammerling, R.C., et al., Kane, R.E., —microscope, horizontal axis immersion: projection of gem et al, Koivula, J.I., et al., Robert, D., et al., and Woodruff, microstructures with, 338 R.E.) —models, demonstration: of axes of symmetry, 207, 209; of —CONNER, L., KOIVULA, J.I., A preliminary gemological ordinary light, 208, 209; of plane polarized light rays, 208, study of synthetic diamond thin films, 41, 106 209; of spinel twin, 209 —ROSSMAN, G.R., New technologies of the 1980s: their Gemmological teaching: in Catalonia, 337; in China, 224, impact in gemology, 237 226, 229; in Hong Kong, 224 —SHIGLEY, J., Contributions to the identification of treated Gemmological tool, sodium polytungstate as a, 364 colored diamonds: diamonds with peculiar color-zoned Gemmological visual aids {see Gemmological teaching aids, JGemm., 1991,22 533

visual) GRAMACCIOLI, CM., (see Pilati, T., et al, and Sosso, F., et Gemmology: 448 al) —contributions to by J.J. Snow, 109 GRANADCHIKOV, B.G., (see Gromov, A.V., et al) —history of, contributions to: Carl Peter Thunberg and Granites: amethyst from géodes in Korean, 204 Ceylon gemstones, 463 —of Nigeria, Central: 196; aquamarine, smoky quartz and —new technologies of the 1980s: their impact on, 237 topaz in, and near contacts of, 197; tin production from, —the current decade, a review of treatments, 240 196; tourmaline-bearing pegmatites associated with, 198 Gems and crystals, how they can transform your life, 381 —of Zimbabwe: 264, 266; pegmatites derived from, 267 Gems, granites and gravels, 380 Graphite: associated with ruby, 487, 489, 495 Gemstones: crystal structure, chemical composition and —as an inclusion: in corundum, 114; in diamond, 306 physical properties of. Part 1, Density, 236, Part 2, GRAZIANI, G., (see Attanasio, D., et al, and Bridges, CR., et Hardness, 377 al.) —depicted on postage stamps, 111, 498, 499 Great Britain: (see also Scotland and Wales) —and early Arabic writers, 446 —agate from, 115, 237 —enhancement and its detection , 239 —gem and ornamental minerals of, 240 —exhibition at the Geological Museum, London: proposed —geology of the northern Pennine orefield, 380 new display and re-location of, 130 —gold rocks of, 244 —modern jeweller's consumer guide to, 244 Greece: ruby-bearing marbles in, 373 —in The Natural History Museum, London: proposed new Greenland: ruby from Fiskenaesset, 109 exhibition and re-location of, 130 GRICE, J.D., Famous mineral localities of Canada, 380 —prospects in Central Nigeria, 195 —BOXER, G.L., Diamonds from Kimberley, Western —relationship between chemical composition and density of, Australia, 372 236 GRIFFIN, W.L., COUSENS, D.R., RYAN, CG., SIE, S.H., —and their origins, 182 SUTER, G.F., Ni in chrome pyrope garnets: a Gem Testing Kit, 55 new geothermometer, 107 Gem Testing Laboratory of Great Britain: merger with the GRILLARD, G., Gemfields, 380 Gemmological Association of GB, 194 GROAT, L.A., RAUDSEPP, M., HAWTHORNE, F.C, GENDRON, F., Le jade en Meso-Amérique, symbole de ERCIT, T.S., SHERRIFF, B.L., HARTMAN, J.S., The pureté et de vie, 107 , amblygonite-montebrasite series: characterization by single- Geology: crystal structure refinement, infrared spectroscopy and —in Brazil: in Bahia, of Serra de Jacobina, 150, 151, 152, 153 multinuclear MAS-NMR spectroscopy, 372 —of Coober Pedy precious stones field, 382 GROMOV, A.V., GRANADCHIKOV, B.G., —and evaluation of the Guinean diamond deposits, 113 ANDREYENKO, E.D., (Typomorphic features of —in Great Britain: of the northern Pennine orefield, 380 emeralds from various deposits), 238 —of Kenya: 484, 485; of Baragoi area, 486; of Mangan ruby Grossular garnet: (see also Garnet) deposits, 484, 485 —from Canada: growth structure, non-cubic symmetry of, 103 —in Zimbabwe: of greenstone belts, 264, 265; of Rhodesian —unusual parti-coloured from Africa, 444 craton, 266, 267 Growth structures: Germany: —as an aid to distinguishing between natural and synthetic —agate from: deposits in the Idar-Oberstein area, 107; from gemstones: 344; of amethyst, 479, 481, 482; of citrine, 482; the Harz region, 111; in Saxony, 240 of emerald, 427, 431, 434, 438; of ruby, 476, 479; of —museums in West Germany, 445 sapphire, 472, 474, 476 —Saxony: agate from, 240; gemstones of, 375; minerals of the —of grossular garnet, 103 Erzegebirge, 375 —in optical uniaxial gemstones, microscopic determination of, Gersdorffite as an inclusion in emerald, 501 344 GIA: Gem Trade Lab notes, 42; 106, 179, 237, 306, 441 —in sapphire, 350, 372 —international gemmological symposium, 504 GRUBESSI, O., AURISICCHIO, C, CASTIGLIONI, A., GIEUSSE, P.J., (see Rink, W.J., et al.) Lo smeraldo delle miniere dei faroni, 372 Gifts to the Association: 45 —The Pharaohs' forgotten emerald mines, 164 GILLBERG, L., Opaler i Australia, 237 GRUNDMANN, G., MORTEANI, G., Emerald Gilson synthetics (see Synthetic and simulated gemstones) mineralization during regional metamorphism: the GIS gem identification system, 180, 309 Habachtal (Austria) and Leysdorp (Transvaal, South Glass: (see also Synthetic and simulated gemstones) Africa) deposits, 238 —foiled, imitating cubic zirconia, / 79 —SCHÄFER, W., HOFER, H., Smaragde aus der —helenite, made from Mount Saint Helens ash, 105 Kesselklamm, eine interessante Neuentdeckung im —imitating black onyx seal stones, 106 Untersulzbachtal, 372 —imitating opal, 108 Guatemala: Jadeite from, 131, 307, 370 —iridescent, Letter to the Editor, 56 GÜBELIN, E., (see Bridges, CR., et al) —natural iridescent, from Mexico, 107 Guinea: —radioactivity of some greenish yellow, 181 —diamond from: geology and evaluation of deposits in, 113; —uranium: used as imitations and in triplets, radioactivity of, production, 378 181; probable, in the form of an egg, 306 GULIANI, G., RODRIGUEZ, CT., RUDEA, F., Les GLENISTER, D.A., (see Pienaar, H.S.) gisements d'emeraude de la Cordillère Orientale de la GODOVIKOV, A.A., BULGAK, L.V., (Fersman), 107 Colombie: nouvelles données metallogèniques, 237 GOEBEL, M., DIRLAM, D.M., Polynesian black pearls, 107 GUNASEKERA, H.P.N.J., (see Perera, S.Z., et al.) Goethite: as an inclusion in emerald, 159, 161, 423, 441 GUO, J., (see also Wang, F.) Gormanite: as an inclusion in quartz, 374 —WANG, F.Q., Chicken-blood stone, 307 GOSLING, J.G., An unusual agate from Guyana, 76 Guyana: agate, unusual, from, 76 GOUPIL, V., Les évangéliaires précieux, 107 —diamond development and exploration in, 444 GRAESER, S., (see Weibel, M., et al.) 534 JGemm., 1991,22

Hackmannite, 42 HLAING, U.T., Myanmar diamonds from north to south, HAHJL, R.G., Opals of the Never-Never, 380 307 HAMMOND, C, Introduction to crystallography, 380 HÖBELT, K.H., Opale von Yowah, Queensland, Australien, HANANO, J., WILDMAN, M., YURKIEWICZ, P.G., 238 Majorica imitation pearls, 307 HOCHLEITNER, R., Die Sonderausstellung des Fersman- HANCOCK, D.A., (see Malone, F.J., et al.) Museums in München, 108 HANNEMAN, W.W., Sodium polytungstate as a —Blauer Euklas aus Zimbabwe, 108 gemmological tool, 364 —WEISS, S., Neue mineralfunde aus Pakistan und HÄNNI, H.A., A contribution to the distinguishing Afghanistan, 442 characteristics of sapphire from Kashmir, 67 HODGKINSON, A., Padparadscha - what is meant by this —Ein Beitrag zu den Erkennungsmerkmalen der Kashmir- term? 442 Saphire, 372 —Visual optics, 108 —Irisierendes natürliches Glas aus Mexiko, 107 Hodgkinsonite: pink, from Franklin Furnace, New Jersey, —Les feldspaths, 107 USA, 369 —Les gemmes du groupe des beryls, 372 HOFER, H., (see Grundmann, G., et al.) —Letter to the Editor, 250 HOFMEISTER, W., (see Bank, H., et al.) —WEIBEL, M., Ursache des Katzenaugen-Effekts bei HOLBECHE, S., The power of gems and crystals: how they erhitzen Zirkonen aus Sri Lanka, 107 can transform your life, 381 HARDER, H., Klare und trübe Korunde als Rohsteine für HOLDAWAY, M.J., (see Dyar, M.D., et al.) warmbehändelte Saphire aus Sri Lanka, 179 Holt, R., Gifts to the Association, 45 —Spinell - attraktive, aber wenig bekannte Edelstein 108 HOLZHEY, G., Untersuchung einer Opal-Imitation, 108 HARDING, R.R., (see also Kanis, J.) Honduras, opal report from, 379 —ZOYSA, E. GAMINI, Sapphirine from the Kolonne area, Hong Kong: Gemmological Association of, 225, 226 Sri Lanka, 136 —gemmological teaching in, 224, 225, 226 Hardness: use in gem testing, 377 —imitation onyx seal stones from, 106 HARGETT, D., (see also Fryer, C.W., et al, and Koivula, J.I., —jade auctions in, 446 étal.) Hope diamond, 41, 106 —Jadeite of Guatemala: a contemporary view, 307 HOPKINS, C, (see Sersen, W.J.) HARTMAN, J.S., (see Groat, L.A., et al.) Hornblende: as an inclusion in corundum, 86 Hauyne: cause of colour in, 372 'Howlers', (examination mistakes), 19 Harvard diamond, 371 HOYOS, M.A., (see lifante, G.) HAWTHORNE, F.C., (see Groat, L.A., et al.) HTEIN, W., (see Huang, U.T., et al.) Heavy liquids: di-iodomethane and all that, Letter to the HUANG, U.T., AUNG, Z., HTEIN W., Radioactivity in Editor, 387; methylene iodide, uses of, 365; sodium some minerals in the Mogok, 442 polytungstate, advantages of, density determination with, HUGHES, R.W., Corundum, 310 physical properties of, preparation of, 364, refractive index —Talkin' 'bout gem-testing instruments, 108, 307 related to density, 365 —There's a rumble in the jungle - the sapphire face-lift face- HEFLIK, W., (see Natkaniec-Nowak, L., et al.) off saga, 442 Helenite (see Glass) —SERSEN, W.J., Vietnamese ruby, 442 Hematite: associated with rose quartz, 277, 278 HUNSTIGER, C, Darstellung und Vergleich primärer —imitation (see Synthetic and simulated gemstones) Rubinvorkommen in metamorphen Muttergesteinen, Part —as an inclusion: in amethyst, 204, Vickers micro-indentation 1, 109; Part 2, 179; Part 3, 373 hardness test on, 205, X-ray analysis, energy dispersive, of, HURLBUT, CS., (see also Kopf, R.W., et al.) 205, 206, X-ray powder diffraction data for, 205; in —KAMMERLING, R.C., Gemology, 448 cordierite (see Iolite below); in emerald, 159, 161, 241, 441, HURWIT, K.N., (see Fryer, C.W., et al.) 501; in iolite, 305, 372 ; in zircon, 42 HUTTON, D.R., TROUP, G.J., ESR spectrum of Australian HEMRICH, G.L., The jade work of India, 372 synthetic Biron emerald, 442 HENN, U., (see Bank, H., et al.) —Cordierit aus Süd-Norwegen, 372 Identification methods, old and new, 240 —BANK, D., BANK, F.H., Red and orange corundum (ruby Idocrase (see Vesuvianite) and padparadscha) from Malawi, 83 Ilmenite: —BANK, H., Blaue Saphire aus Malawi, 779 —as an inclusion: in emerald, 241; in star rhodolite, 16, 17 —BANK, H., On the colour and pleochroism of Cu-bearing Inamori stones (see Synthetic and simulated gemstones) green and blue tourmaline from Paraiba, Brazil, 238 Inclusions: —BANK, H., Über die Farbe der Sodalith-Minerale: Sodalith, —of actinolite/tremolite in emerald, 156, 158, 268, 271, 272 Lasurit (Lapis lazuli) und Hauyn, 372 —in agate, of dendrites,459, 461 —BANK, H., BANK, F.H., Orangefarbene Korunde aus —of ajoite in quartz, 441 Malawi, 108 —of albite in emerald, 421, 423, 501 —BANK, H., BANK-SCHERNER, M., Rubine aus dem —of allanite: in emerald, 157, 158; in sapphire, 74, 372 Pamir-Gebirge, UdSSR, 373 —of almandine-pyrope in diamond, 179 —REDMANN, M., BANK, H., Gem thaumasite from the —in amethyst, of hematite, 204, 205 Black Rock Mine, South Africa, 334 —of amphibole: in emerald, 241; in iolite, 305 Hennessy, Mrs L., Obituary, 116 —of anorthite in corundum, 86 Hermans, Mr J.S., Obituary, 504 —of apatite: in corundum, 114; in emerald, 157, 161; in Hessonite garnet: colour filter test on, 213 sapphire, /10, 201; in sapphirine, 138, in zircon, 108 —from Sri Lanka, 180 —in beryl, of tourmaline, 377 Heterosite: associated with rose quartz, 274, 283 —of biotite in emerald, 106 HICKS, W.H., Editorial appreciation, 108 —of boehmite: in corundum, 114; in ruby, 88, 487, 488; in HISS, D.A., Geuda transforms Sri Lanka's 'City of gems', 108 sapphire, 110,179 HLAING, T., The characteristics of Burmese spinel, 108 —of breunnerite in emerald, 157 JGemm., 1991,22 535

—of bunch-like crystals in thaumasite, 335 305, of.hematite, 305, 372, 395, of lepidocrocite, of —of calcite: in emerald, 106, 157, 421, 423; in ruby, 42 magnetite, 395, of pinite, 305; in cat's-eye, of whitish fibres, —of carbonates in emerald, 241, 421 396 -—causing optical effects, 460 —of kyanite in garnet, 377 —in chicken-blood stone, of cinnabar, 307 —of lazulite in quartz, 237 —of chalcopyrite in emerald, 241 —of lepidocrocite: in emerald, 159, 161; in iolite, 395 —of chlorite in emerald, 156 —of limonite in emerald, 159, 161 —of chrome muscovite in ruby, 488 —of magnetite: in emerald, 501; in iolite,395 —of chromite in emerald, 156, 159, 501 —of mica: in emerald, 155, 156, 158, 161, 241, 271, 272; in —in chrysoberyl, of rutile, 395 garnet, 377 —of cinnabar in chicken-blood stone, 307 —of molybdenite in emerald, 159, 161, 501 —of clinopyroxene in garnet, 377 —of negative crystal containing liquid and a gas bubble in —clues to identity, 113 thaumasite, 335 —in cordierite (see Iolite below) —in olivine: of diopside, of serpentine, 370 —in corundum: (see also Sapphire and Ruby below) from East —in opal: of quartz, 105; whitish, egg-like, 306 Africa, of apatite, of boehmite, of graphite, of rutile, 114; —of orthite (see allanite above) from Malawi, of anorthite, 86, of boehmite (?), 88, of —of pargasite in sapphire, 70, 73, 74, 372 hornblende, 86, of rutile, 86, 87, of zircon, 86, 87 —of parisite in emerald, 421, 423 —in diamond: of almandine-pyrope, 179; of garnet, colour- —of pentlandite in emerald, 241 change, 179; of graphite, 306; of silicon carbide, 374 —of phlogopite in emerald, 441 —of diamond: in garnet and zircon, 377 —of pinite in iolite, 305 —in diopside, of goethite, 395 —of plagioclase in sapphire, 73, 74, 372, 376 -^of diopside in olivine, 370 —of pyrite in emerald, 159, 241, 421, 423 —of dolomite in emerald, 106, 157, 423 —in pyrope, of forsterite, 374 —in emerald: from Brazil, from Capoeirana, of biotite, of —in quartz: of ajoite, 441; of gormanite, 374; of lazulite, 237; calcite, of dolomite, 106, from Nova Era, acicular growth of rutile, 286; of tourmaline, 285, 286; two-phase, 274, 286 tubes, two- and three-phase, 109, from Santa Teresifla, of —of quartz: in emerald, 157, 161, 421, 423; in opal, 105 amphibole, carbonates, chalcopyrite, hematite, ilmenite, —in ruby: from Burma, of calcite, of rutile, 42; from Kenya, of mica, pendandite, pyrite, spinel, talc, 241, from Socotö, boehmite, 487, 488, of chrome muscovite, 488, of rutile, of actinolite/tremolite, 156, 158, of allanite, 157, 158, of 487, 488, 489; from Malawi, of boehmite (?), 88, of rutile, apatite, 157, 161, of bruennerite, 157, of calcite, 87, of zircon, 87 157,chlorite, 156, of chromite, 159, of dolomite, 157, of —of rutile: in chrysoberyl, 395; in corundum, 114; in emerald, emeraloVberyl, 159, of feldspar, 157, of goethite, 159, 161, 241; in garnet, 377; in rose quartz, 286; in ruby, 42, 88, of hematite, 159, 161, of lepidocrocite, 159, 161, of 487, 488, 489; in sapphire, 70, 71, 72, 73, 74, 87, 179, 372, limonite, 159, 161, of mica, 155, 156, 158, 161, of 376, 439; in star rhodolite, 16, 17; in zircon, 42 molybdenite, 159, 161, of pyrite, 159, of quartz, 157, 161, —in sapphire (see also Corundum above): from Australia, of of talc, 156, of tourmaline, 157, 159; from Colombia, of zircon, age of, 236; from India, in Kashmir, of allanite, 74, albite, 421, 423, 501,of calcite, 421, 423, of carbonates, 372, of dust clouds and lines, 70, 71, of pargasite 70, 73, 421, of dolomite, 423, of fluids, 418, 419, 420, of goethite, 74, 372, of plagioclase, 73, 372, of rutile, 70, 372, of 423, of halite, in three-phase, 419, 420, of parisite, 421, tourmaline 70, 73, 74, 372, twin lamellae in, 70, 71, of 423, of pyrite, 421, 423, of quartz, 421, 423; from uraninite, 73, 74, 372, of zircon, 70, 73, 74, 372; from Madagascar, of goethite, of hematite, of limonite, of Malawi, of boehmite, of rutile, of zircon, 179; from Nigeria, phlogopite, 441; from Pakistan, of chromite, of gersdorffite, of apatite, 201, of zircon; from Thailand, of apatite, of of hematite, of magnetite, of molybdenite, of talc, 501; from boehmite, 110; of plagioclase, of rutile, 376; from USA, in Zimbabwe, of actinolite/tremolite, 268, 271, 272, of mica, Montana, of rutile, 439 271, 272 —in sapphirine, of apatite, 138 —in emerald, synthetic: Lennix, 41; Pool, 41; Russian —in sellaite, of fluid, of growth tubes, of three-phase, 103 hydrothermal, 105 —of serpentine in olivine, 370 —of emerald/beryl in emerald, 159 —of silicon carbide in diamond, 374 —of feldspar in emerald, 157 —oî spessartine, in topaz: optical microscopy of, X-ray powder —of forsterite in pyrope, 374 diffraction analysis of, 367 —in garnet: of clinopyroxene, diamond, kyanite, mica, rutile, —of sphene in garnet, 377 sphene, and zircon, 377 —of spinel in emerald, 241 —of garnet, colour-change, in diamond, 179 —in star rhodolite : causing star effect, 16; of ilmenite, 16, 17; —geofingerprints, 109 of rutile, 16, 17; of zircon, 16 —of gersdorffite in emerald, 501 —in taaffeite, of uraninite, 239 —of goethite: in diopside, 395; in emerald, 159, 161, 423, 441 —of talc in emerald, 156, 241, 501 —of gormanite in quartz, 374 —in tanzanite cat's-eye, of parallel channels, of two phase, 397 —of graphite: in corundum, 114; in diamond, 306 —in thaumasite: of bunch-like crystals, 335; of negative crystal —of hematite: 161; in amethyst, from Korea, 204, 205, containing liquid and a gas bubble, 335 Vickers micro-indentation hardness test of, 205, X-ray —in topaz: of limonite-stained dislocation channels, 460, 109; analysis, energy dispersive, of, 205, 206, X-ray powder of spessartine, 366 diffraction data for, 205, 206; in emerald, 159, 241, 441, —of tourmaline: in beryl, 377; in emerald, 157, 159; in rose 501; in iolite, 305, 372, 395; in zircon, 42 quartz, 285, 286; in sapphire, 70, 73, 74, 372 —hidden beauties of gemstones, 109 —of uraninite: in sapphire, 73, 74, 372; in taaffeite, 239 —of hornblende in corundum, 86 —in zircon: of apatite, 108; of diamond, 377; of hematite, 42; —of ilmenite: in emerald, 241; in star rhodolite, 16, 17 of rutile, 42 —importance of in gem evaluation, 459, 460 —of zircon: in garnet, 377; in ruby, 86, in sapphire, 70, 73, 74, —influence of on crystal structure, 106 86, 179, 201, 236,372; in star rhodolite, 16 —in iolite: in aventurescent, of amphibole, 305, of apatite (?), India: aquamarine from, 110, 308 536 JGemm., 1991,22

—bone, carved, from 440 — aventurescent: from Australia, 305; from India, 395 —Cambay bead industry, diamond drill used in, 91 —<:at's-eye, 239, 309, 396 —emeralds from: thermal conductance, 234 —from India: aventurescent, inclusions in, 395; cat's-eye, —iolite from: aventurescent, inclusions in, 395; cat's-eye, parallel fibres in, pleochroism in, 396 parallel fibres in, pleochroism in, 396 Irradiation (see also Treated stones): —jade work of, 372 —detection of in blue topaz, 178, 371 —moonstone from, identified as andesine, 41 —of diamonds, 42, 179, 442; —ruby from Alipur, Mysore, 180 —of white topaz from Nigeria, 202 —sapphire: from Kashmir, characteristics of, 67; Isotopes used in exploration for gemstones, 114 determination of, 372; engraved, 371 Italy: —zircon from Orissa, 42 —emerald from: in Val Vigezzo, chemistry of, 172; lattice Indonesia: parameters, 172, 173, 177 —diamonds from: in Kalimantan, nitrogen-defect aggregation —gem materials of, 371 characteristics of, 446 —olivine from: transparent green, in Val Malenco, Sondrio, Induced neutron activation analysis of zircon, 201 370 Information sources in Earth sciences: bibliographies, —XXII International Gemmological Conference in, 38, 181 abstracts and indexes, 112 Ivory: elephant, stuctural difference from bone and vegetable —computerized information services, 111 ivory, 105 Infrared spectra (see Spectra, infrared) —rare types of, 305 Infrared spectrometry/spectroscopy (see Spectrometry/ —structural differences between elephant ivory, vegetable Spectroscopy, infrared) ivory and bone, 105 Instruments: (see also Chelsea Filter, Microscope, Reflectivity —vegetable, structural difference from elephant ivory and meter, Refractometer, Thermal conductance meters) bone, 105 —Alpha-test thermal conductance meter, 233 —Bead buyers and parcel pickers filter set, evaluation of, 212: JACQUES, A.L., (see Taylor, W.R., et al) Aqua-Filter, 212; Blue Filter, 213; Deep Green Filter, 213; Jade: (see also Jadeite and Nephrite) Ruby Filter, 213 —alluvial deposits, development of from jade lodes, 444 —Brewster-angle refractometer, 100, 102 —along Burma's jade trail, 444 —Ceres Diamond Probe, 375 —ancient jade, preface to collected and illustrated works on, —Chelsea Filter: identification with, 240; similarity of to the 378 Hanneman Aqua-Filter, 212; transmission spectrum, 240; —auctions: in Burma, 374; in Hong Kong, 446 375 —black, a dilemma, 131 —colorimeter, spinning disc tristimulus, 338 —carvers and their customers in Ming China, 441 —computer software for gem identification: Gemdata, 111; —in Central America, 1Q7 GIS, 180, 309 —Chinese: carvers and their customers in Ming China, 441; —conoscope (see Figure-O-Scope below) exhibition of, 370; flowers in, 376; in Khotan, 378, sand- —Eickhorst Thermolyzer, an additional use for, 374 buried ruins of, 446, visits to High Tartary, Tarkand and —endoscope, pearl, 10, 331 Kashgar, 446 —fibre optic cold light illuminator EK-1, 111 —dilemma of the 1980s, 374 —Figure-O-Scope, use of, 113 —-like gemstones, ureyite in, 226 —Gem Diamond Pen, 375 —in Korea, 371 —Gemeter, 97, 98 —market in, worldwide view of, 372, 443 (2) —Gemexpert, 98, 99 —neolithic carving of in China, 242 —Gem Testing Kit, portable mini, 55 —origin of, 374 —gold-meter, 445 —of the Pacific, 439 —goniometer, single circle, 337, 338 —sawing of, 439 —Jeweler's Eye, 97 —search for, the, 447 —linicon LV-125 vacuum pump, 309 —from Taiwan, prehistoric zooanthropomorphic earrings, 446 —Martin Gem Analyser, 98, 99 —trouble at the mines, difficulties in working the Burma jade —Medo Hand vacuum tweezers, model MH-100, 309 tracts, 445 —Mettler B5, B6, M5 balances, radiation alert on, 309 —work in India, 372 —microscopes: dark-field illuminator for gemmological, 180; Jadeite (see also Jade): horizontal axis immersion, 338, 344; Kiowa, an inexpensive —black: gemmological properties, 131,132; similarity of to conversion unit for, 440; measuring ocular used with, 351, some amphiboles, 134; geological occurrence, 134; 427; Sortoscope, 114; stereoscopic, SM-4G, SMS-10, 111; structure of, in thin section, 133; X-ray diffraction, stereozoom SZM-1, SMZ-2 with phototube, 111 identification by, 132 —Presidium DiaMeter - System Berger, 443, 444 —characteristics of, 374 (2) —Presidium Mini-Mate heat-probe, 444 —from Guatemala, 307, 370 —radiation alert (see Meltler balances above) —from Japan: from Niigata, good quality green, blue, purple, —Rayner DiamondScan, 98, 100 black and white, 308 —Rayner Diamond Tester Mk 4, 54 —treated: dyed, detection of, 370; impregnated with plastic, —sample holders: three-axial, 350, 351; two-axial, 427 179; waxed, 444 —talkin' 'bout gem-testing instruments, 108, 307 —trouble at the mines, difficulties in working the Burma jade —Treasure Chest gem tester, thermal conductivity probe, 306 tracts, 445 —tweezers, diamond-grit impregnated, potentially destructive, JAIN, H., (see Xu, M.Y., et al.) 308 Japan: diopside, gem-grade chromian, from the Sano River, Intergem Fair 1990, 249 375 Intergemlab Group, 117 —jadeite from Niigata, 308 Iolite (see also Cordierite): —pearls, cultured: baroque black, 306; from Kashikojima, 7, —from Australia: aventurescent, 305 9; from Lake Biwa, 8, 9, 10 JGemm., 1991,22 537

—ruby from Hida metamorphic belt, 180 crystals from Tanzania, 307 JAQUE, F., (see Iifante, G., et al.) —McCLURE, S.F., MENZHAUSEN, J., The legendary JARRY, A., Excursion à Madagascar, 238 Dresden Green diamond, 443 Jasper from Germany, 240 KANIS, J., ARPS, C.E.S., ZWAAN, P.C., 'Machingwe': a JEFFRIES, B., (see Malone, F.J., et al.) new emerald deposit in Zimbabwe, 264 Jensen, Mr B., Obituary, 504 —HARDING, R.R., Gemstone prospects in Central Nigeria, Jet, imitation (see Synthetic and simulated gemstones) 195 Jeweler's Eye reflectivity meter, 97 KARANTH, R.V., The diamond drill used in the Cambay Jeweler's eye, The, 115 bead industry, 91 Jewelled book bindings, 107 KARFUNKEL, J., (see Ferreira, J.A.M., et al.) Jewellery: beyond the glitter, 383 KARWOWSKI, L., DORDA, J., The mineral-forming —earrings: from antiquity to the present, 381; prawn claws as, environment of 'Marmaros diamonds', 109 440; prehistoric zooanthropomorphic from Taiwan, 446 Kashan synthetics (see Synthetic and simulated gemstones) —master jewellers, 383 KATO, M., (Incidence-radiation relations between the —mourning, 104 incidence rays through the pavilion), 373 —nineteenth century, in the collection of Nancy and Gilbert —(Nomograph for calculating facet cutting angles), 373 Levine, catalogue of, 115 —(Nomographs for diamond incidence-radiation), 373 —of the 1980s, 240 —(Nomographs of diamond incidence-radiation on a —photography of: backgrounds, choice of, 290; depth of field, pavilion), 373 maximization of, 289; lighting, 287, 288, 289; special —(The scintillation by the incident rays through the pavilion), effects, 290 373 —prawn claws as earrings, 440 Kauri gum: carvings, reconstructed, 305 —understanding jewellery, 182; corrigendum, 249 —from New Zealand: mining, occurrence, physical properties, JOBBINS, E.A., (see also Shigley, J.A., et al.) 104 —XXII Gemmological Conference, Italy 1989, 38 —red, 440 —SCARRATT, K., Some aspects of pearl production with KAZMI, A.H., SNEE, L.W. (Eds), Emeralds of Pakistan: particular reference to cultivation at Yangxin, China, 3 geology, gemology and genesis, 244 Journal of Gemmology corrigenda: Vol. 22, No. 1, inside KELLER, PETER C, Gemstones and their origins, 182 front cover, 119; No. 3, Gemdata advertisements, 249, KELLY, S.M.B., (see also Brown, G., et al.) inside front cover, 249 —Using the spectrosope. A personal assessment of the Jupiter-Five, the world's largest opal, 242 contribution to gemmology of J.J. Snow, FGAA, FGA, 109 —BROWN, G., Synthetic periclase, 109 Kaersutite: (see also Amphiboles) possible presence of in black KENT, D.G., Rewarding 'howlers', 19 stones resembling jadeite, 132, 133, 134 Kenya: geological framework of, 485 KAMMERLING, R.C., (see also Hurlbut, CS., Kane, R.E., —geology of Baragoi area, 486 et al., and Koivula, J.I., et a/.,) —ruby from: from Mangari, electron microprobe analysis, —KANE, R.E., KOIVULA, J.I., McCLURE, S.F., An 489, 491, 492; geological occurrence, 372, 484, 485; investigation of a suite of black diamonds, 442 metamorphic formation, PT conditions of, 491, 494, 496; —KOIVULA, J.I., An interesting imitation of jadeite, 238 minerals associated with, 487 —KOIVULA, J.I., An investigation of a dyed quartzite —sapphire from: cuttable blue from Lodwar, 103; new resembling sugilite, 373 discoveries of, 42 —KOIVULA, J.I., An unusual assembled inclusion specimen, KERRICK, D.M., The Al2Si05 polymorphs, 448 459 KEVERNE, R., A worldwide view of the Jade market, 373, —KOIVULA, J.I., An update on assembled emerald 443 (2) specimens from Africa, 373 KEY, R.M., OCHIENG, J.O., The growth of rubies in south­ —KOIVULA, J.I., Examinations of a plastic coated, 'sugar east Kenya, 484 treated' opal, 442 K-feldspar: associated with ruby, 487; electron microprobe —KOIVULA, J.I., Opals displaying cat's-eye effects, 443 analysis of, 492 —KOIVULA, J.I., Star rhodolite garnet from Tanzania, 16 —in estimating temperature during metamorphism, 494 —KOIVULA, J.I., Thermal alteration of inclusions in —giant crystals of, in rose quartz-bearing pegmatites, 274, 'rutilated' topaz, 109 276, 277, 278, 280 —KOIVULA, J.I., Two strongly pleochroic chatoyant gems, KIDWELL, A.L., Famous mineral localities: Murfreesboro, 395 Arkansas, 374 —KOIVULA, J.I., FRITSCH, E., An examination of KIEFERT, L., (see also Schmetzer, K.) Chrysoprase from Goiäs, Brazil, 443 —SCHMETZER, K., The microscopic determination of —KOIVULA, J.I., KANE, R.E., Examination of an structural properties for the characterization of optical interesting cultured blister pearl, 180 uniaxial natural and synthetic stones. Part 1: General —KOIVULA, J.I., KANE, R.E., Gemstone enhancement and considerations and description of the methods, 344, Part 2: its detection in the 1980s, 239 Examples for the applicability of structural features for the KAMPF, A.R., (see Kane, R.E., et al) distinction of natural emerald from flux-grown and KANE, R.E., (see also Fryer, C.W., et al. ,Kammerling, R.C., hydrothermally-grown synthetic emerald, 427, Part 3: et al.y and Koivula, J.I., et al.) Examples for the applicability of structural features for the —KAMMERLING, R.C., KOIVULA, J.I., SHIGLEY, J.E., distinction of natural and synthetic sapphire, ruby, amethyst FRITSCH, E., The identification of blue diffusion-treated and citrine, 471 sapphires, 307 KIM, W-S, Hematite inclusions in Eonyang amethyst from —KAMMERLING, R.C., MOLDES, R., KOIVULA, J.I., Korea, 204 McCLURE, S.F., SMITH, C.P., Emerald and gold Kimberlite: treasure of the Spanish galleon Nuestra Senora de Atocha, —in Canada: investigations of 110, 239; microdiamonds in, 180 239 —KAMPF, A.R., KRUPP, H., Well-formed tsavorite gem —in Guinea: diamond-bearing pipes, 113 538 JGemm., 1991,22

KING, J.E., (see Souza, R.A., et al.) Kyocera synthetics (see Synthetic and simulated gemstones) KING, V.T., (see Lhoerst, J.J., et al., and Robinson, G.W.) Labradorite: KINNUNEN, K.A., MALISA, E.J., Gem-quality Chrysoprase —associated with ruby: 487, 491; electron microprobe analysis from Haneti-Itiso area, central Tanzania, 373 of, 492 KINNY, P.D., (see Coenraads, R.R., et al.) LAHL, B., Achat und Jaspis zwischen St Egidien und KLEYENSTÜBER, A.S.E., (see also Campbell, I.C.C.) Hohenstein-Ernstthal in Sachsen, 240 —Observations on a pyrope-almandine garnet, 239 LANG, A.R., (see Frank, F.C., et al.) KLYAKHIN, K., (see Platonov, A.N., et al.) LANG, H.M., (see Dyar, M.D., et al.) KLYAKHIN, V.A., (see Platonov, A.N., et al.) Lapis lazuli: banded, 306 Knischka synthetics (see Synthetic and simulated gemstones) —from Chile: geological occurrence, 370 KOIVULA, J.I., (see also Fritsch, E., et al., Kammerling, —distinguished from imitation and artificially coloured lapis R.C., et al, Kane, R.E., et al, Kopf, R.W., et al, and by UV-VIS spectra, 235 Robert, D.,etal.) —imitation (see Synthetic and simulated gemstones) —Geofingerprints, 109 Larimar (see Pectolite) —Snail shells in amber, 443 LARSSON, T., Adelstener bland Fältspaterna, HI —The hidden beauties of gemstones: - Artistry through the —Den Förbisedda Adelstenen, 240 microscope, 709 —Värmebehandlade bla safirer, 374 —BOEHM, E., KAMMERLING, R.C., Diamond grit- LASNIER, B., (see Gauthier, J.-P.) impregnated tweezers: a potentially destructive gemological Lawson Clarke, Mr F.E., Obituary, 44 tool, 308 Lazulite: gem quality, from Brazil, 370 —FRITSCH, E., The growth of Brazil-twinned synthetic —as an inclusion in quartz, 237 quartz and the potential for synthetic amethyst twinned on Lazurite: cause of colour in, 372 the Brazil law, 109 LEAMING, S.F., (see also Barnes, L.C., et al.) —FRYER, C.W., Forsterite in Arizona pyrope, 374 —From the mines in the mountains to the rocks in the river. —FRYER, C.W., KAMMERLING, R.C., Spessartine garnet The development of alluvial jade deposits from jade lodes, in Brazilian topaz, 366 444 —FRYER, C.W., KANE, R.E., KAMMERLING, R.C., A —On the origin of jade, 374 black jade dilemma, 131 Lechleitner synthetics (see Synthetic and simulated gemstones) —KAMMERLING, R.C., A gemmological review of LEDOUX, L.A., (see Cassedanne, J.P.) Colombian emeralds, 239 LEGUEY, S., (see Garcia Gimenez, R., anJLifante, G.) —KAMMERLING, R.C., A gemmological study of 'Opalite' LE MAGUER, D., (see Dubois-FournierJ., et al.) and 'Opal Essence', 110 LENAIN, B., (see Dubois-FournierJ., et al.) —KAMMERLING, R.C., An investigation into three Lennix synthetics (see Synthetic and simulated gemstones) imitation opalized shells, 110 LEOPOLD, M., SCHRAMM, M., Schleifwürdige, grüne —KAMMERLING, R.C., An unusual Indian aquamarine, Peridote aus Lanzarote, 43 308 Lepidocrocite as an inclusion in emerald, 159, 161 —KAMMERLING, R.C., Examination of a gem spinel crystal Lepidolite associated with rose quartz, 274, 283, 284 from the Pamir Mountains, 110 Letters to the Editor: —KAMMERLING, R.C., Gem news, 42, 110, 180, 239, 308 —Farn, A.E., 451 [2], 444, —Hanni, H.A., 250 —KAMMERLING, R.C., Gemmological properties of —Mitchell, R.K., 122, 387 emerald from Nova Era, Minas Gérais, Brazil, 109 —Nelson, J.B., 321 —KAMMERLING, R.C., FRITSCH, E., FRYER, C.W., —Read, P.G., 322 (2) HARGETT, D., KANE, R.E., The characteristics and —Rolfe, W.D.I., 186 identification of filled diamond, 43 —Sadler, P.A., 56 —KAMMERLING, R.C., FRITSCH, E., Gemmological —Scandella, S., and Schiffinan, G.A., 122 description of a glass imitation emerald from Zambia, 239 —Scarratt, K., 120 —KAMMERLING, R.C., FRITSCH, E., Gemmological LEUNG, I.S., Silicon carbide cluster entrapped in a diamond investigation of a synthetic spinel from the Soviet Union, from Fuian, China, 374 300 LEVINE, G., VOOKLES, L.L., The jeweler's eye, 115 —KAMMERLING, R.C., FRYER, C.W., Gormanite in LEWAND, E.A., (see Nassau, K.) quartz, 374 Leybourn-Needham, Mr G., Obituary, 504 KOMATSU, H., (Origin and a counterplan of 'Uroko' (scaly LHOEST, J.J., GAUTHIER, G.J., KING, V.T., The spot) on the surface of pearls), 374 Mashamba West mine, Shaba, Zaire, 374 KOPF, R.W., HURLBUT, CS., KOIVULA, J.I., Recent LIBORIO, G., (see Bianchi Potenza, B, et al.) discoveries of large diamonds in Trinity County, California, Liddicoatite (see Tourmaline) 309 LIEBER, W., Broken Hill, 111 Korea: amethyst from Eongyang, hematite inclusions in, 204 —Smithsonit von der Kelly Mine, New Mexico, USA, 111 —jade in, 371 LIEN, C.-M., (see Sung, W.-H.) KORTTNING, S., Achate aus dem Harz, /// LIFANTE, G., JAQUE, F., HOYOS, M.A., LEGUEY, S., KOVACS, E., Letter. Preliminary assessment of gem Testing of colourless natural diamonds by room identification system (GIS) software, 309 temperature optical absorption, 142 KROSCH, N.J., Queensland Chrysoprase, 444 Lighting techniques for microscopic observation, 374 KRUPP, H., (see Kane, R.E., et al.) Light sources: (see also Instruments) Kyanite: —which is the better for testing and selling gemstones ?, 241 —associated with ruby: 485, 486; colour of, 489, 490; electron limonite: as an inclusion in emerald, 159, 161, 441 microprobe analysis, 492; high Cr203 content, 491; LIND, T., (see Banks, H., et al.) poikilitic grains of, 489 Linde synthetics (see Synthetic and simulated gemstones) —in estimating temperature during metamorphism, 494 Linicon LV-125 vacuum pump, 309 —as an inclusion in garnet, 377 LINTILHAC, J.-P., Black pearls of Tahiti, 245 JGemm., 1991,22 539

LINTNER, B., Along Burma's jade trail, 444 —species status of, 259 LINTON, T., (see also Brown, G.) Mettler balances, B5, B6, M5: radiation alert on, 309 —Lighting techniques for microscopic observation, 374 Members' meetings: —Radiation alert, 309 —London: 45, 116, 185, 246, 311, 384, 449, 504 —BROWN, G., A dark-field illuminator for gemmological —Midlands Branch: 45, 116, 185, 246, 311, 384, 449, 504 microscopes, 180 —North West Branch: 117, 185, 246, 311, 384, 449, 504; —BROWN, G., Economic microscopes for gemmologists, 111 corrigendum, 249 —BROWN, G., Medo Hand vacuum tweezers, model MH- MENG, K.H., (see Diehl, R.) 100 and Linicon LV-125 vacuum pump, 309 MENZHAUSEN, J., (see Kane, R.E., et al.) —BROWN, G., Presidium DiaMeter - System Berger, 445 MERCER, I.F., Crystals, 183 —BROWN, G., Presidium MiniMate, 444 MERCER, M., (see Fritsch, E., et al.) —BROWN, G., The gold-meter, 445 MERIGOUX, H., (see Martin, F., et al.) LOBORIO, G., (see Sosso, F., et al.) Metamictization of zircon, 447 LOWE, E.J., The jade dilemma of the 1980s, 374 Meteorites, diamonds in, 42 Lucas, Mr R., Obituary, 185 Methylene iodide: change of name, Letters to the Editor, 387, Luder, Mr J.G., Obituary, 116 451 Lumsden, Miss J.G., Obituary, 311 Mexico: coral, black, exploited in the Mexican Caribbean, 444 —glass, iridescent natural, from, 107 MAAS, H.H., Museen in Westdeutschland, 445 —opal from: black, chatoyant, 444; egg-like inclusion in, 306; McAUGHTRIE, G., An evaluation of the 'Gemdata' gem in Querétaro, geology of, mines in, 371, quartz inclusions identification program, 111 in, 105 —A preliminary assessment of the gem identification system —quartz from: Herkimer-type crystals, 42 (GIS) software, 180 MEYER, A.B., The nephrite question 1888, 375 McCLURE, S.F., (see Kammerling, R.C., et al, and Kane, MEYER, R., (see Bartoli, F., et al.) R.E., etal) Mica: (see also Biotite, Fuchsite, Lepidolite, Muscovite and McCOLL, D., PETERSON, O.V., Titanite crystals from the Phlogopite) Harts Range, Central Australia, 374 —associated with ruby, 485, 487 Macedonia: ruby in marble at Prilep, 373 —as an inclusion: in emerald, 155, 156, 158, 161, 241, 271, McKAY, DJ., O'DONOGHUE, M., Computerized 272; in garnet, 377; in ruby, 488 information services, HI Microcline: hyaline, from Brazil, 370 MACKENZIE, R.K.W., An additional use for the Eikhorst Microscope: (see also Instruments) [sic] Thermolyzer, 374 —colour measurement with, 376 MacPHERSON, H G., Agates, 115 —dark-field illuminator for gemmological, 180 McNeilly, Mr H., Obituary, 504 —economic, for gemmologists, 111 Madagascar: gem-quality minerals of, 238 —lighting techniques for microscopic observation, 374 —orthoclase, yellow from Itrongahy, 239, 242, 447 Microspectrofluorescence of corundum, 106 —ruby, geological occurrence at Ankaratra, Gogogogo, and Mineralogy, handbook of, 379 Vatomandry, 373 Minerals: encyclopedia of, 183; corrigenda, 249 Magnetite as an inclusion in emerald, 501 —gems, granites and gravels, 380 Malachite from Australia, 242 —glossary of mineral species, 448 —in FMS-IGMS-MSA symposium on azurite and related —Goldschmidt's world locality index of, 183 copper carbonates, 378 —Larousse of, 382; corrigendum, 450 —possible oiling of in antiquity, 402 —localities, famous, of Canada, 380 Malagasy Republic (see Madagascar) —and rocks, pocket guide to, 183 Malawi: amethyst, sceptre, from, 110 —of Salzburg, 115 —corundum from: red and orange, 108; in the Chimwadzulu —of Switzerland, 383 Hills, 83 —Welsh, 379 —ruby from: 104, 373; cathodoluminescence in, 43; crystal MISIOROWSKI, E.B., Jewelry of the 1980s: a retrospective, morphology, 476; growth structures in, 476, 478 240 —sapphire from: gemmological properties and inclusions, 179 MITCHELL, R.K., Bead buyers and parcel pickers filter set, MALISA, E.J., (see Kinnunen, K.A.) 212 MALONE, F.J., HANCOCK, D.A., JEFFRIES, B., The —Letter to the Editor, 122, 181, 309, 387 Western Australian pearling industry, 181 —Some thoughts on snuff-bottles, 111 MANDARINO, J.A., (see Fleischer, M.) MIYAMOTO, M., AKAISHI, M., OHSAWA, T., Margarite: YAMAOKA, S., FUKUNAGA, O., Morphology and —associated with ruby: 487, 495; alteration of ruby to, 489; formation process of diamond from glassy carbon, 111 electron microprobe analysis, 492 MIYATA, T., (An introduction to gem mines of Pakistan.), Marialite: (see also Scapolite) 375 —end-member of scapolite group, 259; species status of, 259 Mizzonite (see Scapolite) MARTIN, F., MERIGOUX, H., ZECCHINI, P., Reflectance MOK, K.F., (see Tang, S.M., et al.) infrared spectroscopy in gemology, 181 MOLDES, R., (see Kane, R.E., et al.) Martin Gem Analyzer, 98, 99 MÖLLER, R., Filatelia y gemas, 111 MARTINI, M., (see Attanasio, D., et al.) Molybdenite as an inclusion in emerald, 159, 161, 501 MASCETTI, D., (see also Bennett, D.) Mono-bromonaphthalene, change of name, Letters to the —TRIOSSI, A., Earrings from antiquity to the present, 381 Editor, 387, 450 Medo Hand vacuum tweezers, 309 MONTGOMERY, R.S., In the dark: separating synthetic and Meionite: (see also Scapolite) natural gems by ultraviolet spectroscopy, 445 —content in scapolite: estimated from colour, 263, from Montgomeryite associated with rose quartz, 282 refractive index, 259; plotted against specific gravity 260; MOON, M., (see Fritsch, E., et al.) end-member of scapolite group, 259 Moonstone: from India, identified as andesine, 41 540 JGemm., 1991,22

Moraesite associated with rose quartz, 283 —from Australia: in Cowell, 577, geological occurrence, 375; MOREL, B., The French crown jewels, 115 in Dungowan,305 Morganite: (see also Beryl) differences from pink beryl due to —characteristics of, 374 (2) differing crystal field symmetry ofMn3* ions, 112 —from China: in Kuen-Lun mountains, 439; neolithic carving —from Pakistan: in pegmatites, 377 of, 242 —from USA: in California, in Maine, 376 —from Chuncheon mine, Korea, 371 Morion (see Smoky quartz) —deposits on the Karakash River, 441 Morocco: azurite from Bou Beker mine, 242 —earrings, prehistoric, from Taiwan, 446 MORTEANI, G., (see Grundmann, G.) —geology, production and reserves, world review of, 439 MRÂZEK, L, Gemstones of Nicaragua, 43 —neolithic carving of in China, 242 Mtorolite, 181 —nephrite question, the: origin of jade artifacts found in MUHLMEISTER, S.M., (see Fritsch, E., et al) America, 375 MULUS, J., (see Ramseyer, K.) —in New Zealand: prehistoric usage of, 269 MUMME, I.A., The world of sapphires, 381 —orange peel, 439 Muscovite associated with rose quartz, 274, 277, 280, 282, —'rind' of, 376 284 —in Taiwan: prehistoric earrings, 446; treasures of the Peinan —associated with ruby: 487, 495; C^C^ content, 491; culture, 447 electron microprobe analysis of, 492 —toughness of, 370 —in estimating temperature during metamorphism, 494 Neutron magnetic resonance: impact of on gemmology, 237 Museums: NEWBURY, C, The diamond ring: business, politics and —British Museum (Natural History) (see The Natural History precious stones in South Africa, 381 Museum below) News of Fellows: 45, 116, 246, 311, 384, 449, 504 —Carnegie Museum of Natural History, Pittsburgh: the New Zealand: kauri gum from, 104 Hillman Hall of Minerals and Gems in, 377 —nephrite from: prehistoric usage, 269 —Cleveland Museum of History, Ohio: inauguration of Nicaragua, gemstones of, 43 gemstone collection in, 236 NICHOL, B., Nephrite jade deposits near Cowell, 375 —Fersman Mineralogical Museum, Moscow: collections NICHOLS, M.C., (see Anthony, J.W., et al.) described, 107; specimens from exhibited in Munich, 108 NIEDERMAYR, G., Fluorit Mineral des Regenbogens, 448 —Geological Museum, London: Gemstones exhibition, Nigeria: aquamarine from, 195, 196, 197 proposed new exhibition and re-location of, 130 —beryl in, 196, 197, 198 —Green Vaults of Dresden: Colombian emerald crystals in, —elbaite from, 376 356 —emerald from: 202; determination of angle formed by two —Leningrad Mining Institute Museum, 447 families of growth planes in, 351; in Jos, absorption in UV, —Museum of London: Cheapside Hoard of Jewellery, new 418, infrared spectrum, 218; low Mg and Na content, 411 display of, 249; Treasures and Trinkets exhibition, 249 —gahnite from, 202 —Natural History Museum, Paris: mineral collections of, 382 —gemstone prospects in, 195 —Natural History Museum, Vienna: Colombian emeralds in, —Kaduna State: from Jemaa district, in decomposed basalts, 356 sapphires, 198, 199, zircons, 200, 201; gahnite from, 202 —San Diego Museum of Natural History: Scripps Hall of —Plateau State: in Jos district, cassiterite from granites, 196; Mineralogy at, 114 Kefifi, tourmaline-bearing pegmatites SE of, 197, 198; in —The Natural History Museum, London: mineral collections Rafine Gabas Hills, aquamarine, smoky quartz and topaz, of, 378; Mineral Gallery displays, proposed new exhibition geological occurrences of, 197; and re-location of, 130; Pain collection of gemstones from —sapphire from: 195, 198, 199, 201; in alkali basalt, crystal Burma, bequest of, 259 morphology of, 472, 474; growth structures, 474, 475 —Topkapi Palace, Istanbul: Colombian emeralds in, 356 —topaz in, 195, 197 —in West Germany, 445 —tourmaline in, 195, 197, 198 Myanmar: (see also Burma) diamonds from, 307 —zircon from: 195; absorption spectrum, 200; chemical analysis of, 201 NAITO, Y., (Gem-grade chromian diopside found in the Niobotantalite: associated with rose quartz, 274, 282, 283, upper stream of the Sano River, Yamanashi Prefecture.), 284 375 North America: (see also Canada and USA): Namibia: diamond mining, recent developments, 237 —pearls, freshwater from, 5 —quartz crystals from the desert, 110 —turquoise from, 242 NANA, G.P., (see Bianchi Potenza, B., et al) Norway: cordierite from, 372 NASSAU, K., Amethyst and citrine, 111 —ruby from, 180 —Gemology - the current decade, 240 NOTIS, M.R., (see Xu, M.Y., et al) —Synthetic gem materials in the 1980s, 240 —Two types of historical traps: on 'Diamond Softening' and OBERHOLZER, W.F., (see Weibel, M., et al) the 'Antiquity of Emerald Oiling', 399 Obituaries: Mr R. Ahrend, 184; Mr W.A. Burslem, 246; —LEWAND, E.A., Mildly radioactive rhinestones and Senora Speranza Cavenago Bignami Moneta, 184; Sir synthetic spinel and glass triplets, 181 Frank Claringbull, 311, 330; Mr A.C. Colclough, 311; Mr NATKANIEC-NOWAK, L., HEFLIK, W., SOBCZAK, N., K.C. Cole, 45; Mrs A. Eaton, 116; Mrs L. Hennessy, 116; SOBCZAK, T., Ein Beitrag zur Farbe niederschlesischer Mr J. S. Hermans, 504; Mr B. Jensen, 504; Mr F.E. Chrysoprase, 43 Lawson Clarke, 44; Mr G. Leybourn-Needham, 504; Mr NELSON, J.B., Gemmological teaching in Catalonia, 337 R. Lucas, 185; Mr J.G. Luder, 116; Miss J.G. Lumsden, —Gemmological teaching in Hong Kong and China, 224 311; Mr H. McNeilly, 504; Mr R. F. Parcel, Jr, 449; Mr D. —Letter to the Editor, 321 F. Rossiter, 185; Miss E. A. Short, 45; Mr J.J. Snow, 116; Nephrite: alluvial deposits, development of from jade lodes, Mr A.M.N. Thurlow, 246; Mr E.H. Tindall, 384; Mr E. < 444 Trillwood, 185; Mr A. Valta, 504; Mrs C. Wong, 246 -in America: origin of artifacts found in, 375 Obsidian, 242 JGemm., 1991,22 541

OCHIENG, J.O., {see Key, R.M.) 492 O'DONOGHUE, M., {see also McKay, DJ.) Parcel, Jr., Mr R.F., Obituary, 449 —Kamienie szlachetne i ozdobne wysp brytyjskich, 240 Pargasite as an inclusion in sapphire, 70, 73, 74, 372 —Kvartz, 382 Parisite: —Secondary literature: bibliographies, abstracts and indexes, —from Colombia: absorption spectrum, 422; associated with 112 emerald, 238, 357; as an inclusion in emerald, 421, 423; —The pocket guide to rocks and minerals, 183 transparent, faceted, 369 OHSAWA, T., {see Miyamoto, M., et al.) Patagonia: fossil pine cone from, preserve^! in chalcedony, 308 Oligoclase: Pearls: {see also Organic gemstones) —associated with ruby: 487, 491; electron microprobe analysis —Abernethy, 6 of, 492 —adornment with, by native Americans, 332 Olivine: {see also Forsterite and Peridot) —from Australia: in Northwest, large cultured, 235; in —distinction of from sinhalite by single crystal X-ray Western, industry in, 180 diflractometer, 112 —from Bahrain, {see also The Gulf below) 5, 6 —green, transparent from Val Malenco, Italy, 370 —baler shell pearl, 439 OLLIVER, J.G., {see Flint, DJ., et al.) —baroque, natural, drilled and plugged, 306 Opal: adventures, 244 —beads, drill holes chipped, 107 —aluminium, role of in the structure of Brazilian, 369 —black: colour obtained by silver treatment of, 237; of Tahiti, —from Australia: fire, flow structure and dendrites in, 105; in 245 Lightning Ridge field, 379, 441; as nobbies or nuts, 238; —blister: worked to imitate a natural pearl, 179; representing opal fields, flooding in, 42; occurrences of gem quality, 23 the goddess Kwan Yin, 110, 180 —bloody opals...!, 441 —from Burma, sectioned cultured pearl, 8 —from Brazil: aluminium, role of in the structure, 369; —Cairncross necklace, 6 chatoyant, 236; gemmological properties of, 370; pinfire —chemical analysis of, minor elements in, 377 from Boi Morto, 444 —from 'cherry-stone clam', 42 —chatoyant: 236, 309; 443, 444; in triplets, 444 —from China: in Yangxin, cultured non-nucleated, baroque, —common, scenic from Peru, 305 10, cultivation methods, 11, 12, 13, 15, examined by X- —electrical properties of, 114 radiography, 15, quality of, 10, 11 —fire: flow structure and dendrites in, 105; from Louisiana, —cultured: black, auction of in Cook Islands, 386; blister, 376 representing the goddess Kwan Yin, 110, 180; coated with —from Honduras, 379 black/brown calcareous concretion, 306; dyed, black, 179, —imitation {see Synthetic and simulated gemstones) 305, 441, pink, 107; grey with exceptionally thick layer of —journey with colour, Lightning Ridge field, NSW, 379 conchiolin, 237; large, from NW Australia, 235; —from Mexico: chatoyant black, 444; quartz inclusions in, —cultured,ncn-nucleated: from China, baroque, drilling of, 105; in Querétaro, geology of, mines in, 371 10, cultivation at Yangxin, 11, 12, 13, 15, examined by X- —of the Never Never, 380 radiography, 15, quality of, 10, 11; from Japan, cultivation —from Peru: common, scenic, 305 at Lake Biwa, 8, problems in identification of, whitish —structural differences between precious opal and potch, 378 appearance of, X-radiograph of, 10 —synthetic {see Synthetic and simulated gemstones) —cultured, whole and beaded: bouton, 442; from Burma, 7, 8; —treated {see Treated stones) from Japan, baroque black, 306, cultivation at Ago Bay, 7, —triplets: cat's-eye, 308 9, nucleus, new type of, 306, quality, 7, 8; from Polynesia, —from USA: in Idaho, used in cat's-eye triplets, 308; in naturally coloured black and grey, 107, 245, 306; from Louisiana, fire opal, 376 South Seas, 7; in Western Australia, 181 —white, fine quality large cut, 441 —endoscope, 10, 331 —world's largest, Jupiter-Five, to be sold, 242 —imitation {see Synthetic and simulated gemstones) Optical uniaxial gemstones: growth planes seen in cross- —from Japan: cultured non-nucleated, from Lake Biwa, 8, sections of, 352 identification problems of, X-radiograph of, 10; cultured —crystal faces and characteristic angles in, determination of, whole and beaded, baroque black, 306, cultivation at Ago 347,349,350,351 Bay, 7, 9, new type of nucleus, 306, quality, 7, 8 —structural properties of, and the determination of, 344, 350, —natural, freshwater: from America, North and South, 5; 351,352,354 from Bangladesh, 5; from the Concho River, pink, 42; from Optical uniaxial minerals: significant crystal angles of, 346 Scodand, Abernethy, Bill, pearl fisher, 5, Abernethy pearl, Organic gemstones {see Amber, Bone, Coral, Ivory, and 6, Cairncross necklace, 6, fishing methods, 5, 6, 7, lustre of, Pearls) 5, 6; from USA, west Texas, necklace of brownish-pink, Orthoclase: yellow, from Madagascar, 239, 242, 447 306 —natural, sea water: production and trading in The Gulf, 4, 5 Padparadscha {see Corundum and Sapphire) —from Polynesia: cultured, naturally coloured black and grey, Pakistan: apatite, pink, from Nagar, 447 107, 254, 306 —diopside, green, from Kaflu (?), 447 —from Qatar: {see also The Gulf below) 5; typical fishing boat —emerald: typomorphic features of, 238; from Mingora, from, 4 lattice parameters of, 172, 173, 177; from Swat Valley, high —scaly spot ('uroko'), origin and prevention of, 374 Cr content, 416, thermal conductance, 234 —from Scotland: natural freshwater, 5, 6, 7, 243 —gem mines of, 375 —-shell industry in Western Australia, 181 —new mineral discoveries in: in pegmatites in, 377; in Stak- —testing: musings on, 331; with endoscope, with X-rays, 331, Nala, 442 —from Tahiti, black, 245 —stibiotantalite in Stak-Nala, 442 —The Gulf: {see also Bahrain and Qatar above) pearl fishing PALMER, A., Poona WA and the seekers of its emeralds, 382 and trading in, 4; decline in, reasons for, 5 PANNILA, A.S., {see Perera, S.Z., et al.) —tissue graft cultured {see cultured non-nucleated above) Paragonite: —treated: {see also Treated stones) dyed, black, 179, 305, pink, —associated with ruby: 487; electron microprobe analysis of, 107; with silver to dye black, 237; with tellurium dye, JGemm., 1991,22 542

possibly, 441 filter, 240, 375 —from USA: from west Texas, necklace of natural freshwater, —Niektore wspolczesne metody badan kamieni szlachetnych, 306 375 PEARSON, G., Multiple chatoyancy in Australian sapphire, PLATEN H.v. (see Bank, H., et al.) 445 PLATONOV, A.N., TARAN. M.N., KLYAKHIN, K., Pectolite: from the Dominican Republic, 242, 369; geological KLYAKHIN, V.A., On two colour types of Mn^-bearing occurrence, 369; mineral characteristics and mining beryls, 112 history, 372 PLENDL, H.S., (see Rink, WJ., et al.) Pegmatites: alexandrite, possible origin in, 105 Poland: —in Austria: at Leysdorp, emeralds associated with, 238 —Chrysoprase from: cause of colour in, 43; in Silesia, at —in Brazil: rose quartz in, 273, 274 Szklary, 377 —complex granitic, occurrence of spessartine and topaz in, —quartz crystals from, 109 368 Polynesia, black cultured pearls from, 107, 306 —emeralds: associated with, 238; in, 267, 268, 269, 271 PONAHLO, J., Kathodolumineszenz-und Absorption­ —euclase in, 108 sspektren gelber Saphire, 375 —in Kenya: ruby-bearing, geological occurrence of, 485, 486 —Mikrospektralphotometrie der Edelstein-Kathodo- —in Nigeria: geological setting of, 198; tin-bearing, 196; lumineszenz, 112 tourmaline-bearing, 197, 198 —Quantitative Kathodolumineszenz von Rubinen aus Malawi, —rose quartz-bearing, 273: mineralogy of, 276; schematic 43 section of different textural paragenetic types, 274 Pool emeralds (see Synthetic and simulated gemstones) —in Norway, cordierite in, 372 POPOVA, E.E., (see Wilke, H.-J.) —in Pakistan, new mineral discoveries in, 377 Postage stamps depicting corals, crystals, gems and mining —ruby in desilicated plumasitic, 485, 487 activities, 498, 499 —in Zimbabwe: emeralds associated with, 267, 268; euclase POUGH, F.H., Chrysoprase, 112 in, 108; as intrusions in greenstone belts, 264, 265, 267; Prehnite from Australia, 104 PEILE, J., Trouble at the mines, 445 Presidium DiaMeter - System Berger, 443, 444 PEMADASA, T.G., Gem deposits of South West Sri Lanka, Presidium Mini-Mate heat probe, 444 445 Psilomelane: black gem material, 180 Pentlandite as an inclusion in emerald, 241 Pyrite: PERERA, S.Z., PANNILA, A.S., GUNASEKERA, H.P.N.J., —associated with: emerald, 238, 357; rose quartz, 274, 284; EDIRIWEERA, R.N., Anomalous behaviour of certain ruby, 487 geuda corundums during heat treatment, 405 —as an inclusion in emerald, 159, 241, 421, 423 Peridot (see also Forsterite and Olivine): Pyrope-almandine: (see also Garnet) observations on, 239 —cuttable green, from Lanzarote, 43 Pyrope garnet: (see also Garnet) —grains of in Hawaiian lavas, 242 —from Arizona, forsterite inclusion in, 374 —from USA: production at San Carlos, Arizona, 308 —colour filter test on, 213 PERRY, C.L., (see Dyar, M.D., et al.) —Ni in chrome pyrope garnet: a new geothermometer, 107 Persian crown jewels, emeralds in, 356 —spessartine from East Africa, 103 Personalities behind the gem world: Kokichi Mikimoto, 104 Pyroxene (see also Jadeite): Peru, common opal from, 305 —characteristics, absence of, in thin section of black jadeite, PETERSON, O.V., (see McColl, D.) 133 PETROV, I., Role of natural radiation in tourmaline coloration: discussion, 240 Qatar (see also The Gulf): pearls from,4, 5 PETSCH, E., (see Bank, H., et al.) Quartz: (see also Amethyst and Citrine) 382 PHILIPPY, R., (see Bartoli, F., et • al.) —alpha quartz, short-lived blue cathodoluminescence in, 375 PHILLIPS, G., BROWN, G., Mtorolite, 181 —Alpine, habit of, 237 Phlogopite: —associated with emerald, 238, 357 —associated with ruby: 487; electron microprobe analysis of, —blue, coloured by inclusions: of ajoite, 441; of lazulite, 237 492 —from Brazil: rose quartz, massive, 275, in Minas Gérais, —electron microprobe analysis of, 170, 492 276, crystallized, 280; smoky quartz, 274, 276, 277; —in estimating temperature during metamorphism, 494 window quartz, 276, 280 —as an inclusion in emerald, 441 —cabochons backed with computer chips, 444 Phosphosiderite associated with rose quartz, 283 —crackled and dyed: (see also Treated stones) set as 'purple Photography: onyx', 444; sold as green amethyst, 180; technique used in —of jewellery: backgrounds for, 290; depth of field, antiquity, 399 maximization of, 289; lighting, 287, 288, 289; special —critical angle of, 97 effects, 290 —crystals: characteristic habit, 349; cross-sections of seen by PIENAAR, H.S., GLENISTER, D.A., The Stellenbosch gern rotation, 353; faces and angles, selected, of, 346; Herkimer- index: a numerical approach to gemstone identification, 245 type from Mexico, 42 PILATI, T., (see also Sosso, F., et al.) —distinction from scapolite by single-crystal X-ray —GRAMACCIOLI, CM., SOSSO, F., Identification of diffractometer, 112 gemstones by single-crystal X-ray diffractometer, 112 —from Germany: in the Erzegebirge area, gem-quality from Pinite as an inclusion in iolite, 305 Ehrenfriesdorf, smoky quartz from Zinnwald, 375 Plagioclase (see also Albite, Andesine, Bytownite, Feldspar, —gormanite inclusions in 374 Labradorite and Oligoclase): —as an inclusion: in emerald, 157, 161, 421, 423; in opal, 105 —associated with ruby, 485, 487, 495 —man-made inclusions in, 460 —electron microprobe analysis of, 170 —from Mexico: Herkimer-type crystals, 42 —in estimating PT conditions during metamorphism, 494 —milky to translucent, associated with rose quartz, 274, 284, —as an inclusion in sapphire, 73, 74, 372, 376 285 PLASZYNSKA, M., Measurement of transmission of Chelsea —morion (see Smoky quartz below) J Gemm., 1991,22 543

—from Namib desert, chandelier-like masses of crystals Refractive index: measurement by reflection, L.C. Trumper's —in Nigeria: smoky, in or near granite contacts, 197 thesis on, 97 —phantom crystals in, 106 —relationship to reflectivity, Fresnel equation for, 97 —from Poland: 'Marmaros diamonds' from the Carpathians, Refractometer (see also Instruments): 109 —Brewster-angle, 102 —reflectivity of, 97 —critical angle and total internal reflection in 98 —rose quartz: from Brazil, colour, fading of, 274, 284, Regency synthetics (see Synthetic and simulated gemstones) crystallized, 273, 274, 280, 282, 283, 284, 285, 370, 376, RETTY, A.T., (see Tang, S.M., et al.) fetid odour of, 275, 278, 280, 282, 283, gemmological Rewarding 'howlers', 19 properties, 285, 286, inclusions, 285, 286, massive, 273, Rhodesia (see Zimbabwe) 274, 275, 276, 277, 278, 279, 280, minerals associated Rhodolite: (see also Garnet) with, 273, 274, 282, pegmatitic occurrence of, 273, 274; —star: from Tanzania, 16; absorption spectrum, 17; from USA, in Connecticut, 42 gemmological properties, 18; inclusions in, 16, 17 —smoky quartz: from Brazil, associated with rose quartz, 274, Rhodonite from Broken Hill, Australia, 111 276, 277; from Nigeria, 197; from USA, in Arizona, 377 RIDD, M., (see Taylor, W.R., et al.) —sunstone, 440 RINK, W.J., GIEUSSE, P.J., PLENDL, H.S., Coloration in —from Switzerland, gem quality crystals, 113 electron-irradiated beryl, 33 —total internal reflection in a polished gem of, 101; Letters to ROBERT, D., Ces nouvelles tailles, vous connaissez ?, 241 the Editor, 321, 322 —Emeraldolite (letter), 445 —from USA: rose quartz from Connecticut, 42 —Emeraldolite, 181 —window quartz, associated with rose quartz, 276, 280 —Mesure de couleur au microscope, 376 Quartzite: —Synthèses de l'émeraude, parts 1 & 2, 112 —dyed: green, imitating jadeite, 238, 239; resembling sugilite, —FRITSCH, E., KOIVULA, J.I., Emeraldolite: a new 372 synthetic overgrowth on natural beryl, 445 QUELLMALZ, W., A brief look at the Saxon Erzgebirge, 375 ROBERTS, W.L., CAMPBELL, T.J., RAPP, G.R., —Die edlen Steine Sachsens, 375 Encyclopedia of minerals, 183 ROBERTSON, R.S., SCOTT, D.C., Geology of the Coober Radiation alert on some Mettler balances, 309 Pedy precious stones field, 382 Radioactivity: in diamond, irradiated green, 179 ROBINSON, G.W., Famous mineral localities: De Kalb, New —in minerals from Mogok, 442 York, 376 —in rhinestones and synthetic spinel and glass triplets, 181 —KING, V.T., What's new in minerals ?, 376 —in uranium glass, 181 Rockbridgeite associated with rose quartz, 282 RAMSEYER, K., MULLIS, J., Factors influencing short-lived Rocks and minerals, pocket guide to, 183 blue cathodoluminescence of alpha-quartz, 375 RODITI, M., (see Cassedanne, J.P.) RAPP, G.R., (see Roberts, W.L., et al.) RODRIGUES, P., BANERJEE, A., Anwendung der Rare-earth elements, 309 Infrarotspektroscopie in der Edelsteinkunde: RAUDSEPP, M., (see Groat, L.A., et al.) Untersuchungen des Infrarot-Pleochroismus von Dipyr Rayner DiamondScan, 98, 100 (Na-reichen Skapolith), 241 Rayner Diamond Tester Mk 4, 54 RODRIGUEZ, CT., (see Giuliani, G., et al.) READ, P.G., A synthetic by any other name, 112 Rolfe, W.D.I., Letter to the Editor, 186 —Comments on the evaluation of'Gemdata', 111 ROMBOUTS, L., Geology and evaluation of the Guinean —Detection of synthetic emeralds by thermal conductance, diamond deposits, 113 233 ROONEY, M.-L. T., (see Frank, F.C., et al.) —Identification methods, old and new, 140 Roscherite associated with rose quartz, 282 —Identifying synthetic amethysts and filled diamonds, 240 ROSENZWEIG, A., On the 'rind' of nephrite jade, 376 —Letters to the Editor, 322 (2) ROSENZWEIG, D., Flowers in Chinese jade carving, 376 —Reflections on reflectivity, 97 Rossiter, Mr D.F., Obituary, 185 Realgar: gem quality, from Hunan Province, China, 242 ROSSMAN, G.R., (see Fritsch, E., et al, and Woodhead, J.A., REBBERT, C.R., (see Dyar, M.D., et al.) etal.) REDMANN, M., (see also Henn, U., et al.) Royal lavulite (see Sugilite) —Changierender Fluorit aus dem Schwarzwald, 376 Ruby: (see also Corundum) Reflectance infrared spectroscopy (see Spectroscopy, infrared: —absorption spectra (see Spectra, absorption below) reflectance) —boehmite inclusions in, 487, 488 Reflection: —from Burma: damaged by repair to setting, 179; inclusions, —total internal: brilliance dependent on, 101; critical angle, 42; interference figures, variation of during rotation, 350; relationship to, 99, 101; in diamond, 99, 101; Letters to the proton-induced X-ray emission analysis of, 446 Editor, 321, 322; in quartz, 99, 101; in refractometer, 98 —cathodoluminescence in, 43 Reflectivity: of diamond, 97 —colour filter tests on, 213 —Fresnel equation for, 97 —colour intensity related to trace element concentrations in, —measurement of refractive index by, 97 84, 89, —of quartz, 97 —colour zoning in, 88 —refractive index, relationship to, 97 —crystal forms of, 467 Reflectivity meters (see also Instruments): —damaged by repair to setting, / 79 —diamond and its simulants identifiable by, 97 —electron microprobe data, 491, 492 —Gemeter, 97,98 —filled, 442 —Gemexpert, 98, 99 —inclusions in, 86, 87, 88, 487, 488, 489 —history of development, 97 —from Kenya: chemistry, 489, 491; colour zoning, 487, 488, —Jeweler's Eye, 97 498, related to Cr content, 491; electron microprobe —Martin Gem Analyser, 97, 98, 99 analysis, 491, 492; geological occurrences, 484, 485, 486; —Rayner Diamond Scan, 98, 100 inclusions, 487, 488; metamorphic formation of, PT 544 JGemm., 1991,22

conditions of, 491, 494, 496; minerals associated with, 487, —geuda stones: 80; anomalous behaviour of during heat 491,492 treatment, 405; transforms Sri Lanka's 'City of gems', 108 —lamellar twinning in, 88 —growth structures: aid in distinction between natural and —liquid feathers in, 88 synthetic, 471, 472; angled, 350; in Australian, 472, 473, —from Malawi: 104; absorption spectra, 85; 475, 477, 478; in Cambodian, 474, 475; in Nigerian, 474, cathodoluminescence in, 43; chemical analyses of trace 475; in Thai, 474, 475, 477 element content, 84, 85; crystal morphology, 476; growth —heat treatment: (see also Treated stones) of blue, 374; heated structures in, 476, 478; host rock, 83; inclusions, 86, 87, and coated, 440; of Kashmir, 68, 69, 445; from Sri Lanka, 88; variations in colour and physical properties related to clear and opaque raw material for, 179, evidence for in blue, trace element concentrations, 84, 89 80, geuda, anomalous behaviour of during, 405, industry —mica inclusions in, 488 in, 108; of Thai, 110; turned colourless by, 305 —occurrences, primary, in metamorphic rocks: part 1, 109; —inclusions in, 70, 71, 72, 73, 74, 86, 87, 179, 201, 372 part 2, 17% part 3, 372 —from India: from Kashmir, absorption spectra, 68, 446; —physical properties, variations in, related to trace element colour, characteristics and causes of, 67, 68; crystal habit concentrations, 84, 89, of, 67,68; determination of, 372; diagnostic features, 445; —proton-induced X-ray emission analysis of, 446 (2) engraved, 371; heat treatment, 68, 69, 445; historical review —rutile inclusions in, 87, 487, 488, 489 of, 67; host rock, mineralogy of, 67; inclusions 70, 71, 72, —spectra, absorption: 85 73, 74, 372, 446; provenance, commercial importance of, —from Tanzania: absorption spectra, inclusions, 237; in 74 Longido mine, in green zoisite, 114 —from Kenya: growth structures in, 103; new discoveries of, —from Thailand, proton induced X-ray emission analysis of, 42 446 —from Malawi: blue, gemmological properties of, inclusions —from USSR: gemmological properties, geological in, 179; orange, absorption spectrum, 86, host rock, 83, occurrence, inclusions, 373 inclusions in, 86, 87, lamellar twinning in, 80, physical —from Vietnam: 308; in Luc Yen, 442; mines re-opening, 180 properties, 84, trace element content of, 84, 89 —zircon inclusions in, 86, 87 —negative crystal, burst, in, 72 —in zoisite, green, 114 —from Nigeria: colour zoning in, 201; corroded surfaces of, RUDEA, F., (see Giuliani, G., et al.) 201; crystal morphology, 201, 472, 474; in decomposed Russia (see USSR) alkali basalt, 198, 199, 472; growth structures in, 474, 475; RUSTIONI, M., BERTONI, S., BGO, a new material of inclusions in, 201 gemmological interest ?,113 —orange, from Malawi, 83 Rutile: —padparadscha (see also orange above): what is meant by this —as an inclusion: in corundum, 114; in emerald, 241; in term? ,442 garnet, 377; in quartz, rose, causing asterism, 286; in —pargasite inclusions in, 70, 73, 74, 372 rhodolite, star, 16, 17; in ruby, 42, 87; in sapphire, 70, 74, —plagioclase inclusions in, 73, 372 86, 87, 17% 372, 376, 43% in zircon, 42 —rutile inclusions in, 70, 74, 87, 179, 372, 439 RYAN, C.G., (see Griffin, W.L., et al.) —from Sri Lanka: absorption spectra of natural bue, untreated and heat-treated, 81, 82; colour, cause of, 80, 82; Sadler, P.A., Letter to the Editor, 56 colourless, 307; crystal, 40 kg doubly terminated, 180; heat SAMAMA, J.-C, (see Bartoli, F., et al.) treatment, anomalous behaviour of geuda during, 405, clear Sapphire: (see also Corundum) and opaque raw material for, 179, evidence of in blue, 80, —absorption spectra (see Spectra, absorption, below) industry in, 108, of milky -white geuda, 80 —allanite inclusions in, 74, 3 72 —spectra, absorption: 68; of blue, heat -treated and untreated, —in alluvial deposits, 103 81; Letter to the Editor, 250; of orange, 85; of yellow, 375 —apatite crystals in, 201 —star: distinction from synthetic, 445; 12-ray from Australia, —from Australia: in alkali basalt, 472; crystal morphology, 445; from Zaire, 372 472; exploration for, 370; growth structures in, 472, 473, —synthetic (see Synthetic and simulated gemstones) 475; pleochroism in, 397; yellow multi-zoned crystal from —from Tanzania: absorption spectra, colours, inclusions, 237 Anakie, 42 —from Thailand, 376: in alkali basalt, 472; crystal —in basalt: from Australia, 472; crystal morphology, 472, 474, morphology, 474; growth structures in, 474, 475, 477; heat 476; growth structures in, 472; from Nigeria, 196; from treatment, effects of, 110; inclusions, 376'; new deposit at Thailand, 103 Amphoe Bo Phloi, 103 —blue: colour filter tests on, 212; from Malawi, 17% produced —tourmaline inclusions in, 73, 372 by heating geuda, 405, 406; from Thailand, 376; types I —twin lamellae in, 70, 71 and II, characteristics and occurrences of, 80 —two phase inclusions in, 201 —boehmite inclusions in, 179 —uraninite inclusion in, 73, 372 —from Burundi, 180 —from Vietnam: mines re-opening, 180 —from Cambodia: in alkali basalt, 472; crystal morphology, —from USA: Yogo deposit, in Montana, 439 474; growth structures in, 474, 475; in Pailin, angled —world of, 381 growth structure, 350 —yellow: cathodoluminescence of, 375; colour filter tests on, —cathodoluminescence in yellow, 375 213; multi-zoned crystal from Australia, 42 —colour filter tests on, 212 —zircon inclusions in, 70, 73, 74, 179, 201, 372 —colourless from Sri Lanka, 307 —zoning in, 71 —crystal, doubly terminated, 40kg, 180 Sapphirine: as an inclusion in ruby, 136 —crystal forms of, 467 —from Sri Lanka: 104; analyses of, by electron microprobe, by —deposits, geological origin of, 67 inductively coupled plasma spectrometry, 138, by X-ray —diffusion treated (see also Treated stones), 239, 307, 444 diffraction, 136; cut stones of, 140; gem quality material, —dust lines in, 72 140; geological occurrence of, 136, 137, 139; inclusion of —engraved, from Kashmir, 371 apatite in, 138; physical properties, similarity to serendibite, —fissures, healed, in, 70, 71, 72 138 JGemm., 1991,22 545

SARMIENTO, L., (see Cozar, J.S., et al.) SEGNIT, E.R., The XXII International Gemmological SCANDALE, E., (see Annatasio, D., et al) Conference, 181 Scandella, S., Schiflman, G.A., Letter to the Editor, 122 Sellaite: colourless from Brazil, inclusions in, 103 Scapolite: (see also Marialite and Meionite) from Burma: SENA SOBRINHO, M. DE, Notas sobre aluvioés chatoyant, 261; colour, as a guide to composition of, 259, diamantiferas do Estado de Minas Gérais, Brazil, 377 related to refractive index and specific gravity, 260, 262; Serendibite: gemmological properties of, similarity to meionite content in, estimated from physical properties, sapphirine, 138; occurrences, 138 259, 262, 263, plotted against specific gravity, 260; specific SERGUNENKOV, B.B., (Gem scapolite from the gravity, optical data listed in order of, 262 Tarakuloma Ridge (the Pamirs)), 113 —chatoyant, 261 Seriate associated with rose quartz, 284 —colour of, related to composition, 259, 260, 263 Serpentine: (see also Bowenite) —dipyre: gem crystals from USSR, 113; infrared pleochroism —calcite rock dyed to imitate jadeite, 309 of, 2411 a variety of scapolite, 259 —earring, prehistoric, from Taiwan, 446 —distinction of from quartz by single-crystal X-ray —as an inclusion in olivine, 370 diffractometer, 112 SERSEN, W.J., (see also Hughes, R.W.) —marialite content in, 259 —Gemstones and early Arabic writers, 446 —meionite content in, 259, 260, 263 —HOPKINS, C, Al comprar y al vender gemas - que luz es la —mizzonite, a variety of scapolite, 259 major ?, 241 —purple, 179 SHARPE, T., (see Bevins, R.E.) —star, 309 SHATSKY, V.S., (see Sobolev, N.V.) —from USSR: composition, crystal forms, physical properties, SHAW, R., Visits to High Tartary, Tarkand and Kashgsar 113 1868/69, 446 SCARRATT, K., (see also Jobbins, E.A.) SHEAF, C, Jade around the clock. Reflections on jade sales at —Letter to the Editor, 120 Christie's, Hong Kong, 446 SCHÄFER, W., (see also Grundmann, G., et al.) SHERRIFF, B.L., (see Groat, L.A., et al) —Belmont und Sta. Terezinha. Reise zu den brasilianischen SHIGLEY, J.E., (see also Faulkner, J.E., Fritsch, E., et al, and Smaragdminen, 376 Kane, R.E., et al.) Scheelite: colour filter test on yellow, 213 —DIRLAM, D.M., SCHMETZER, K., JOBBINS, E.A., Schiffman, G.A., Scandella, S., Letter to the Editor, 122 Gem localities of the 1980s, 241 SCHLUESSEL, R., Des saphirs étoiles synthétiques...pas Short, Miss E.A., Obituary, 45 comme les autres, 445 SIE, H., (see Griffin, W.L., et al.) —Les saphirs de Bo Ploi (Kanchanaburi-Thailand), 376 Silesia: Chrysoprase from the Szklary massif, 43 SCHMETZER, K., (see also Kiefert, L., and Shigley, J.A., et Silica: bead industry in Cambay, 91 al) —powder: collection and uses of, 92, 95, 96 —Hydrothermally grown synthetic aquamarine manufactured Silicon carbide as an inclusion in diamond, 374 in Novosibirsk, USSR, 309 Sillimanite associated with ruby, 487, 489 —Im hydrothermalverfahren hergestellter synthetischer SILVA, L.T., (see Ferreira, J.A.M., et al) Aquamarin aus der UdSSR, 113 SILVER, LT., (see Woodhead, J.A., et al) —Two remarkable Lechleitner synthetic emeralds, 20 Sinhalite: distinction from olivine by single crystal X-ray —KIEFERT, L., Spectroscopic evidence for heat treatment of diffractometer, 112 blue sapphires from Sri Lanka - extra data, 80 SINKANKAS, J., Contributions to a history of gemmology - —KIEFERT, L., Water in beryl - a contribution to the Carl Peter Thunberg and Ceylon gemstones, 463 separability of natural and synthetic emeralds by infrared SKINNER, B.J., (see Dietrich, R.V.) spectroscopy, 215 SMITH, C.P., (see Kane, R.E., et al.) SCHMIDT, S.T., (see Bank, H., et al) Smithsonite from Kelly Mine, New Mexico, USA, 111 SCHRAMM, M., (see Leopold, M.) SNEE, L.W., (see Kazmi, A.H.) SCHUBNEL, H.-J., Cristeaux précieux, 382 SNEYD, R., (see Brown, G., et al) —Larousse des minéraux, 382 SNOW, J., (see Brown, G., et al) SCHUHBAUER, E., Bemerkenswerte Neufunde von Roten —The use of the Figure-O-Scope in gemmology, 113 Beryllen in den Wah-Wah Mountains, Utah, 445 —BROWN, G., Inamori stones' rough (some observations SCHÜPBACH, T., Ein interessanter Quarz-Epidotfund aus and speculations), 113 dem Val Punteglias, 113 Snow, Mr J.J., Obituary, 116 SCHVOERER, M., (see Bille, C, et al) SNOWMAN, A.K. (Ed), The master jewelers, 383 SCHWARTZ, D., Die brasilianischen Smaragde und ihre Snuff bottles from China, HI Vorkommen: Santa Terezinha de Goias/Go., 241 SOBCZAK, N., (see also Natkaniec-Nowak, L., et al, and —Die chemischen Eigenschaften der Smaragde. I. Brasilien, Sobczak, T.) 376 —SOBCZAK, T., Korale ozdobne, 241 —New aspects of the emerald workings in Colombia, 181 SOBCZAK, T., (see also Natkaniec-Nowak, L., et al, and —Smaragdabbau in Kolombien: Neue Aspekte, 113 Sobczak, N.) —Turmalin als Einschluss in Beryll, 377 —SOBCZAK, N., Die klassischen polnischen Chrysopras - —EIDT, T., COUTO, P.A., The Brazilian emeralds and their Vorkommen von Szklary in Niederschlesien, 377 occurrences: Socotô, Bahia, 147; corrigendum, 249 —SOBCZAK, N.R., Royal Lavulite - nowy kamien ozdobny, SCHWEIGER, R., Diagnostic features and heat treatment of 241 Kashmir sapphires, 445 SOBOLEV, N.V., SHATSKY, V.S., Diamond inclusions in Scotland: agates from, 115; colour in, 237 garnets from metamorphic rocks: a new environment for —gemstones of, 243 diamond formation, 377 —pearls from, 5, 6, 7, 243 Sodalite: cut as beads, 306 SCOTT, D.C., (see Robertson, R.S.) —group, causes of colour in, 372 SCOVILL, J.A., WAGNER, L., The Fat Jack mine, Yavapai Sodium polytungstate: density determination with, 364; County, Arizona, 377 physical properties of, 364; solution,preparation of, 364, 546 JGemm., 1991,22

365; refractive index of, relationship to density, 365 —of scapolite from USSR, 113 SOI, V., {see Sosso, F., et al) Spectra, X-ray, energy dispersive: of hematite, 205 SOLANS, J., {see also Domenech, M.V.) Spectra, X-ray fluorescence: of Lechleitner synthetic emerald, —DOMENECH, M.V., Estructura cristalina, composition 22 quimica y propriedades fisicas de las gemas. II. La dureza, Spectrometry, inductively coupled plasma emission: of zircon, 377 201 SONNELLRATH, J., Brasilianische Andalusite und Zink- —of emerald, 270 Staurolithe von Edelsteinqualitä: Chemismus, —of tourmaline, 494 Bildungsbedingungen, optische und kristallographische Spectroscopy, gamma-ray: in detection of irradiated topaz, Eigenschaften, 241 106, 371 SOSSO, F., {see also Pilati, T., et cd.) Spectroscopy/spectrometry, infrared: —SOI, V., PILATI, T., DIELLA, V., LOBORIO, G., —of dipyre (Na rich scapolite), infrared pleochroism in, 241 GRAMACCIOLI, C.M., Alessandrite sintetica: nuovi dati —of emeralds: for comparison of, from Brazil, Colombia and cristallografici ed analitici, 377 Egypt, 173, 174, 175, 176; classification by , 220; South Africa: andalusite, industrial grade, from, 114 distinction between natural and synthetic, 215, 217; water —emerald from: in Leysdorp, mineralization during absorption bands determined by, 215; water and/or metamorphism, 238 hydroxyl groups, determination of types in, 219 —Kuruman Region: from Kalahari Manganese Field, gem- —impact of on gemmology, 237 quality thaumasite, 335 —reflectance, 181 —ruby in metamorphic rock at Mashishimala, 373 —of synthetic spinel, Russian flux-grown red, 303 —sugilite from mine near Kuruman, 309 —of zircon, metamict, from Sri Lanka, 447 —thaumasite from Black Rock Mine, Kalahari Manganese Spectroscopy, Mossbauer: of natural and synthetic staurolite, Field, 441 South America {see also Argentina, Brazil, Chile, Colombia, Spectroscopy, Raman: impact of on gemmology, 237 Guyana, and Peru) Spectroscopy, ultraviolet: separating synthetic and natural —pearls from, 5 gems by, 445 —emeralds from: in Cobra Mine, thermal conductance, 234 Spessartine garnet: {see also Garnet) colour filter test on, 213 SOUZA, R.A., WILSON, W.E., GANGEWERE, R.J., —as an inclusion in topaz: geological occurrence, 368; late- WHITE, J.S., KING, J.E., The Hillman Hall of Minerals stage growth of, 367; optical microscopy, 367; X-ray and Gems, the Carnegie Museum of Natural History, diffraction analysis, 367 Pittsburgh, 377 Sphalerite: associated with rose quartz, 282 Spain: —colour filter test on, 213 —Barcelona, Club de Talle de Gemas de, activities and Sphene: colour filter test on yellow, 213 facilities, 342, 343 —gem-quality from Harts Range, Australia, 374 —Barcelona School of Gemmology: 339; classroom facilities, —as an inclusion in garnet, 377 340; research at, 341 Spinel: {see also Gahnite) —Catalonia, gemmological teaching in, 337 —associated with ruby, 487 —Catalan language, translation of some gemmological terms —attractive but little-known gemstone, 108 into, 339 —from Burma, Mogok area, 108 SPEAR, P.M., {see Frank, F.C., et al) —cat's-eye, greyish-violet, 239 Spectra, absorption: of beryl, electron-irradiated, 34, 36 —cobalt: absorption spectrum, 444; colour change, 307 —of corundum: orange, 86; red, 85 —colour filter tests: on blue 212; on red, 213 —of diamond: colourless natural, 143, 144; Dresden Green, —from USSR: gem crystal, 110; in marble, 376 443 —growth, characterization and history of, 240 —of emerald: from Afgahanistan, 417, in UV, 418; from —as an inclusion in emerald, 241 Brazil, 415; from Colombia, 411, 412, 413, 414, 416; from —polysynthetic twinning in, 306 Madagascar, 441; from Nigeria, in UV, 418 —from Tanzania: 239; colouring matter determined by —of fluorite, colour-change, 376 spectroscopy, 104 —of Lechleitner synthetic emerald, 22 Spodumene: associated with rose quartz, 277, 283 —of parisite, from Muzo (?), Colombia, 416 —lettuce-green, from Minas Gérais, 376 —of ruby, 85 Sri Lanka: chrysoberyl, rare star, from, 180 —of sapphire: blue, differences in heat-treated and untreated, —corundum from: clear and opaque as raw material for heat- 80,81; Letter to the Editor, 250; orange, 86; yellow, 375 treated sapphire, 179; geuda variety, anomalous behaviour —of spinel, cobalt, 444 of during heat treatment, 405 —of star rhodolite, 17 —emerald, poor quality, from, 180 —of taaffeite, 103 —gem deposits from the south west, 445 —of zircon, 200 —gemstones from: described by Carl Peter Thunberg, 466; Spectra, cathodoluminescence (CL): in distinction between historical accounts of, 463 natural and synthetic stones, 112 —geuda from: anomalous behaviour during heat treatment, Spectra, ESR: of Biron synthetic emerald, 442 405; industry in, 108; transforms 'City of gems, 108 Spectra, fluorescence: of corundum, 106 —iolite, aventurescent, from 395 Spectra, infrared: —sapphire from: {see also Corundum above) colourless, 307; —of emerald: from Brazil, 173, 174, 175, 176, 218, 219, crystal, 40 kg doubly terminated, 180; evidence for heat corrigendum, 249; from Colombia, 173, 174, 175, 176, treatment of blue from, 80; geuda industry, 108; 218, 219; from Egypt, 173, 174, 175, 176; from Nigeria, typical crystal habit of, 467 218; from Tanzania, 221; from Zambia, 218; from —sapphirine from: 104; in the Kolonne area, 136 Zimbabwe, 218, 270 —serendibite from Gangapitya, 138 —of emerald, synthetic: Biron hydrothermal, 218; Chatham —synthetics fashioned to imitate water-worn crystals, 180 flux-grown, 218; Lechleitner hydrothermal, 25, 28, 218; —taaffeite from: absorption spectrum of, colour change in, Russian hydrothermal, 218; Swarovski hydrothermal, 222 103 JGemm., 1991,22 547

—Thunberg, Carl Peter: gemstones of, collected and vapour technique; 41, 106; low pressure growth of, a review described by, 466, commentary on identity of, 466; visited, of diamond film science and technology, 236; morphology 464 and formation process of from glassy carbon, 111; —zircon from: cat's-eye effect in heat-treated, 107; metamict orientation-dependent nitrogen incorporation on vicinals on green with laminated structure, 239; metamictization of, cube growth surfaces, 237; Sumitomo, 41, canary yellow, 447; typical crystal forms of, 468 339 STALDER, H.-A., {see Wiebel, M., et al.) —doublets: backed with computer chips, 444; of emerald, 235; Star stones {see Asterism) of dendritic agate and glass, 308, 459, construction of, 460, Staurolite: Mossbauer spectroscopy of, 441 461, gemmological properties, 462; glass, imitating agate, —synthetic {see Synthetic and simulated gemstones) 460; of tourmaline, 308 —zincian, gem quality, from Brazil, 241 —emerald doublets {see Doublets above) Stibiotantalite from Pakistan, 442 —emerald, imitation: crystals, made from filled crystal, 43, of Stichtite from Australia, 440 fluorite, 309, of glass, 239, 240, of quartz coated with STEIN, M.A., Sand-buried ruins of Khotan, 446 limonite and mica, 308, of quartz fragments cemented with STRASSER, A., Die Minerale Salzburgs, 115 green epoxy, 373; in dyed quartz, 369 Strontium titanate {see Synthetic and simulated gemstones) —emerald, synthetic: detection of, by growth structures, 428, Structural features: {see also Growth structures) 431, 438, by infrared spectroscopy, 215, by thermal —in optical uniaxial gemstones, microscopic determination of, conductance, 233, 322; flux-grown, crystal morphology, 344 431, lattice parameters, 172, 173, 177; syntheses of, 112 Sugilite, 241, 309 (2); Biron hydrothermal, absorption in UV, 418, Cr/V SUNG, W.-H., LIEN, C.-M., A study of zooanthropomorphic ratios in, 411, ESR spectrum, 442, growth structures planes jade earrings of prehistoric Taiwan, 446 in, 425, 437, infrared spectrum, 218, seed plate, orientation Sunstone from Idaho, USA, 239 of, 437, thermal conductance, 234; Chatham flux-grown, SUTER, G.F.,. {see Griffin, W.L., et al.) absorption in the UV, 418, crystal morphology, 431, growth SUTHERLAND, C, {see Brown, G., et al.) structures in, 431, 432, 433, infrared spectrum, 218, 418, SUTHERLAND, F.L., {see Coenraads, R.R., et al.) residual flux, zones of, 433; Emeraldolite, flux-grown Swarovsky synthetics {see Synthetic and simulated gemstones) emerald overgrowth on natural beryl seed, 181, 441, 445, Switzerland: Letters, 445, 446; Gilson, flux-grown, absorption in the UV, —epidote crystals from Val Punteglias, 113 418, crystal morphology, 434, growth structures in, 434, —oolongite, man-made 'garnet', from, 180 435, 436, lattice parameters, 172, 173, seed plates, —quartz crystals from Val Punteglias, 113 orientation of, 434, 435, 436, thermal conductance, 234; —ruby from: in Passo Campolungo, in marble, 373; in Valle Inamori, absorption in the UV, 418; Lechleitner, flux- d'Arbedo and north of Locarno, 180 grown, 31; Lechleitner hydrothermal, 20, absorption Synthetic and simulated gemstones: spectra, 26, 27, colour-causing trace elements, distribution —agate doublet, 459, 461, gemmological properties, 462 of, 22, 23, 24, 25, colour zoning in, 21, 22, 23, 28, types of, —agate, imitation by glass doublets, 460 30, 31, electron microprobe analysis, 23,24, fractures in —alexandrite, synthetic: from USSR, 377 skin on colourless beryl core, 29, infrared spectrum, 25, 28, —amber, imitation: plastic, 179 218, layered growth structure of, 21, 22, 29, pleochroism, —amethyst, synthetic, 237: growth structures in, 482; 27, seed plate, orientation of, 437, similarity to Russian identification of,! 240; seed plate, orientation of, 481; hydrothermal emerald, 30, thermal conductance of coated twinned areas, triangular, in, 482 and of solid, 234, X-ray fluorescence spectra, 22; Lennix —aquamarine, imitation: glass, 440 flux-grown,inclusions, 41, thermal conductance, vanadium —aquamarine, synthetic: hydrothermal from USSR, inclusions in, 41; Linde hydrothermal, seed plate, orientation of, 437; and physical properties, 113, 309 Pool hydrothermal, growth structures in, 425, 437, —assembled stones {see Doublets below) inclusions, 41, nomenclature of, 41, raw material for, 41, —berlinite, synthetic: interference figure, 42 seed plate orientation of, 437; Regency hydrothermal, —beryl, synthetic: Biron, pink, 305 growth structures in, seed plate, orientation of, 437; —Biron {see Synthetic beryl above and Synthetic emerald Russian flux-grown, crystal morphology, 431, growth below) structures in, 431; Russian hydrothermal, absorption —bismuth germanium oxide, a new material of gemmological spectrum, 105, growth structures in, 105, 436, inclusions, interest?, 113 105, infrared spectrum, 218, physical properties, 105, seed —bubbles in, terminology of, Letters, 181, 309 plate, orientation of, 437; Swarovski hydrothermal, infrared —calcite stained to imitate rhodochrosite, 308 spectrum, 222, seed plate orientation of, 436; Vasar, —Chatham {see Synthetic emerald and Synthetic sapphire absorption in the UV, 418 below) —Emeraldolite {see Synthetic emerald above) —chicken-blood stone, imitation, 440 —garnet, man-made: 'oolongite', 180; oulongite, 441; yttrium —citrine, synthetic: seed plate orientation in, 482; growth aluminium gallium garnet, 306 structure in, 481, 482 —gem materials in the 1980s, 240 —coral, imitation: of barium sulphate, 306 —Gilson {see Synthetic emeralds above) —corundum, synthetic {see also Synthetic ruby and Synthetic —glass imitations: of cubic zirconia, 179; of emerald crystals, sapphire below): flux grown crystals, cross-sections of seen 239, 240; of Imperial jadeite, 444; of onyx, 107 ; of opal, by rotation, 353, habit of, 348; stars backed with computer 108; of pectolite, 444; in uranium glass, found to be radio­ chips, 444 active, 181 —cubic zirconia: colour-change, didymium doped, 305; —glass, uranium: found to be radio-active, 181; probable, imitated by foiled paste, 179; yellow with absorption similar radio-active, in the form of an egg, 306 to Cape diamonds, 441 —growth planes, importance of in distinction between —De Beers {see Synthetic diamond below) synthetic and natural gems, 344 —diamond, synthetic: De Beers, distingushed from natural —gutta percha {see Imitation jet below) and simulants by cathodoluminescence, 104, yellow —hematite, silicon imitation of, 305 industrial, largest yet, 444; DLC films grown by chemical —Inamori stone: {see also Synthetic emerald above) inclusions 548 JGemm., 1991,22

and other identifying features in rough, 113 —tsavorite imitated by YAGG, 306 —infrared spectroscopy (see spectroscopy, infrared, below) —turquoise, imitation: of carbonate with plastic binder, 442 —jadeite, imitation: calcite serpentine rock, selectively dyed, —ultraviolet spectroscopy in separating synthetic from natural 309; glass, 444; quartzite dyed green, 238 gems, 445 —jet, imitation: gutta percha, 292, chemistry of, 293, 294, —Vasar (see Synthetic emerald above) distinction from vulcanite, 296, 297, jewellery grade, —vulcanite (see Imitation jet above) composition and gemmological characteristics of, —yttrium aluminium gallium garnet (YAGG) imitating manufacture of, 293, latex, source of, 293, surface tsavorite, 306 deterioration of, 294, 296; vulcanite, 292, chemistry of, SZENICS, T., The rediscovery of axinite at Thornberry 295, distinction from gutta percha, 296, 297, jewellery Mountain near Coarsegold, Madera County, California, grade, composition and gemmological characteristics of, 241 294, 295, latex, source and recovery of, 294, 295 —Kashan (see Synthetic ruby below) Taaffeite: red, with uraninite inclusion, 239 —Knischka created rubies (see Synthetic ruby below) —from Sri Lanka: absorption spectrum, colour change, 103 —Kyocera Corporation products (see Inamori above) Taiwan: prehistoric earrings from, 446 —lapis lazuli, imitation, 42: distinguished from dyed and —treasures of the Peinan culture, 447 natural untreated by UV-VIS spectra, 235 Talc as an inclusion in emerald, 156, 501 —Lechleitner (see Synthetic emerald above) TAN, L.-P., (see Barnes, L.C., et al) —Lennix (see Synthetic emerald above) TANG, S.H., (see Tang, S.M., et al) —Linde (see Synthetic emerald above) TANG, S.M., TANG, S.H., MOK, K.F., RETTY, A.T., —onyx, imitation: glass, 101; quartzite dyed purple, 444 TAY, T.S., A study of natural and synthetic rubies by —oolongite/oulongite: man-made 'garnet', 180, 441 PDŒ, 446 —opal, imitation: glass, 108; plastic, physical characteristics of, TANG, S.M., TANG, S.H., TAY, T.S., RETTY, A.T., 110 Analysis of Burmese and Thai rubies by PIXE, 446 —opalized shells, imitation: composition of, 110 (2), 305 Tanzania: Chrysoprase from Haneti-Itiso area, 373 —opal, synthetic: electrical properties of, 114 —corundum from: 237; from Ngoronghoro, 41 —pearl, blister: two joined to simulate natural pearl, 179 —emeralds from: from Lake Manyara, infrared spectra, 221 —pearl, imitation: Majorica, 307 —ruby from: 237; in green zoisite, from Longido, 709, 114; in —pectolite, imitation: blue Imori stone (glass), 444 Ngorongoro, 373 —periclase, synthetic: 109 —sapphire from 237 —Pool emeralds (see Synthetic emerald above) —spinel from the Umba Valley, 104, 239 —quartz soudé 'amethyst', 305 —star rhodolite from the Kangala Mine, 16 —quartz, synthetic: growth of Brazil-twinned, 109; Russian, —tsavorite from, euhedral crystals of, 307 305; update, 235; —zircon from, 239 —Regency (see Synthetic emerald above) Tanzanite: cat's-eye, 309, 397; parallel channels in, —ruby, imitation: in dyed quartz, 369 pleochroism in, 397 —ruby, synthetic: glass-filled, 442; Kashan flux-grown, crystal —carved, heat treated, 309 morphology, 474; Knischka flux-grown, 178, 309, crystal —colour filter test on, 212 morphology, columnar habit, 479, growth structures in, TARAN, M.N., (see Platonov, A.N., et al) 478, 479; proton-induced X-ray emission study of, 446; TAY, T.S., (see Tang, S.M., et al) star, inclusions in, 107 TAYLOR, A., Emeraldolite (letter), 446 —sapphire, imitation: in dyed quartz, 369 Taylor-Burton diamond, 235 —sapphire, synthetic: cabochons matted on back, 444; TAYLOR, W.R., JACQUES, A.L., RIDD, M., Nitrogen- Chatham flux-grown, crystal morphology, 476, defect aggregation characteristics of some Australasian growthstructures in, 476, 477, 478; colour filter test on diamonds: time-temperature constraints on the source yellow, 213; Czochralski, colourless and pink, 43; difrusion- regions of pipe and alluvial diamonds, 446 treated blue, 440; inclusions in, 442; purple, resembling Thailand: amethyst, 237; star, distinction from natural, 445 —ruby from: analysis by proton-induced X-ray emission, 446 —spectroscopy, infrared: classification of natural and synthetic —sapphire from: in alkali basalt, 472; from Bo Ploi, 376; emerald, 220; to distinguish natural from synthetic emerald, crystal morphology of, 474; growth structures in, 474, 475, 215 477; heat treatment of, 110; new deposit at Amphoe Bo —silicon imitation of hematite, 305 Phloi, 103; undersea exploration for, 110 —spinel, synthetic: bubbles in, terminology of, Letters, 181; Thaumasite: geological occurrences of, 334 309; colour filter test on blue, 212; growth, characterization —inclusions in, 334, 335 and history of, 240; Russian flux-grown red, gemmological —from South Africa: in Kalahari Manganese Field, geological characteristics, 178, 180, 302, 310, 440, inclusions, 178, occurrence, mineralogy of, 334; growth zoning in, 334; 180, 302, 303, 440, infrared spectrometry, 303, similarity to inclusions, 335; physical properties, 334, 336 natural spinel, 304, 440, surface growth features, 303; The Gulf (see also Bahrain and Qatar): triplet, purple, 305; Verneuil, red, physical properties and —pearl fishing and trading in, 4, 5 inclusions, 440 THEMELIS, T., Clues to identity, 113 —staurolite, synthetic: Mossbauer spectroscopy of, 441 —Longido, 114 —strontium titanate: distinguished from diamond by —Oiling emerald, 242 reflectivity meter, 97 —Some inclusions in Umba corundums, 114 —Sumitomo, (see Synthetic diamond above) Thermal conductance: detection of synthetic emeralds by, —Swarovski (see Synthetic emerald above) 233, 234; Letter to the Editor, 322 —a synthetic by any other name, 112 —meters (see also Instruments), 233 —tourmaline doublet (see Doublets above) —of natural and synthetic emeralds, 234 —triplets: opal cat's-eye, 308, 444; synthetic spinel, purple, —of peridot, 322 305; synthetic spinel/uranium glass, found to be radio­ —of sinhalite, 322 active, 181 Thermoluminescence: used to differentiate between natural JGemm., 1991,22 549

and irradiated blue topaz, 178 behaviour of during heat treatment, 405 THUM, R., {see Bente, K., et al) —crackling, ancient practice of in quartz and red stones, 399 Thunberg, Carl Peter: biographical note on, 463; gems of Sri —diamond, filled: characteristics and identification of, 43, Lanka collected and described by, 466 240; glass filler removable, 180; 'Yehuda-filled', 239 Thurlow, Mr A.M.N., Obituary, 246 —diamond, irradiated: blue octahedron, 179; colour zoning in, Tindall, Mr E.H., Obituary, 384 42, 306; green, radio-active, 179; 'umbrella' zoning in Titanite {see Sphene) green, 441 TOMBS, G.A., Argyle diamonds, 446 —'diamond softening', misunderstanding of, 399 Topaz: blue, distinction between natural and irradiated stones —emerald: filled fissures in, 237; metal foils applied to by thermoluminescence, 178 pavilion, 502; oiling, lack of evidence for in antiquity, 402; —from Brazil: in pegmatites, 368; spessartine garnet inclusions oiling, modern practice of, 242, 402, 403^ Opticon in, 368 treatment of Brazilian, 110; repaired with plastic-like infill, —colour filter tests: on blue, 212, 213; on yellow, 213 42; resin treatment, 501; tension cracks filled with oil, 501, —distinction from danburite by single crystal X-ray 502; 'Yehuda-filled', 239 difïractometer, 112 —fillers for diamonds and other gems, 237 —from Germany: violet fron Greifenstein, yellow from —gemmology - the current decade, a review of treatments, 240 Schneckenstein, 375 —gemstone enhancement and its detection, 239 —heat treatment of inclusions in, 460, 109 —jade, waxed, 444 —inclusions in, 367, 460 —jadeite: dyed, detection of, 370; impregnated with plastic, —irradiation: detection of, by gamma-ray spectroscopy, 106, 179; dyed and waxed from Hong Kong, 440 371, by thermoluminescence, 178; of Nigerian, 202 —lapis lazuli, practical recognition of artificially coloured, 235 —from Nigeria: geological occurrences of, 197; white, —malachite, possible oiling of in antiquity, 402 supplied for irradiation, 202 —opal: plastic coated, 309, 442; sugar-treated, 309, 442 —sculpture in bhiish-green, 444 —pearl, cultured: dyed pink, 107; dyed black, 179, 441; Tourmaline: treated with silver to colour black, 237 —associated with rose quartz: elbaite, 283; gem, 273, 274, —quartz, Aqua Aura treatment of, 444 283, 284; schorl, 273, 274, 276, 277, 278, 280, 284 —quartz, dyed: imitating emerald, ruby and sapphire, 369; —associated with ruby: 485, 486, 495; colour, cause of, 491; green, imitating jadeite, 238, 239; man-made inclusions in, electron microprobe analysis, 492; ICP analysis of, 494; 460; purple, used as 'purple onyx' in Indian jewellery, 444; poikilitic grains of, 489 resembling sugilite, 373; sold as green amethyst, 180; —blue and green: coloured by copper and manganese, 178, —ruby: glass-filled, detection of, 239, 442; oiled, 305 180, 238, 306, 447; heat treatment of, 239, 306 —sapphire: blue, heated, 374; blue from Kashmir, 68, 89, 445; —from Brazil: in Minas Gerais, liddicoatite, 239, multi­ blue from Sri Lanka, evidence for heat treatment of, 80; coloured crystals, 447, sceptre elbaite, 242; in Paraiba, blue clear and opaque raw material for heating, 179; coated and and green, 110, 306, 308,447, colour and pleochroism of, heated, 440; diffusion-treated blue, 239; identification of, 238, heat treatment of, 239, 306, intensely coloured from 307, 444; geuda industry in Sri Lanka, 108; glass-filled holes Salgadinho, 371, physical properties of, 178, violet-blue in, 239; heated to make colourless, 305; from Thailand, from new mine at San Jose Baltalha, 179 effects of heat treatment on, 110 —chatoyancy in, 395, 444 —tanzanite, heated to a blue colour, 309 —colour filter tests: on green, 213; on yellow, 213 —topaz: detection of irradiated blue by gamma-ray —colour of, role of natural radiation in, 240 spectroscopy, 106, 371; heat treatment of inclusions in, 460 —crystals from Himalaya Mine, USA, 42 —tourmaline: from Paraiba, heat treatment of green and blue , —elbaite: associated with rose quartz, 283; from Nigeria, 376; 239; heat treatment of purple, 306 sceptre, 242 —turquoise, probable oiling of in antiquity, 402 —as an inclusion: in emerald, 157, 159; in garnet, 377; in rose Tremolite from Afghanistan, 442 quartz, 285, 286; in sapphire, 70, 73, 74, 372 Trillwood, Mr E., Obituary, 185 —liddicoatite, 239 TRIOANI, T., Rare-earths, 309 —from Nigeria: elbaite, 376; in pegmatites, 197, 198 TRIOSSI, A., {see Mascetti, D.) —from Pakistan: new discovery in pegmatites, 377 Triphylite from Minas, Gérais, Brazil, 371 —from USA: in California, crystals from Himalaya Mine, 42; TROUP, G.J., {see Hutton, D.R.) a Hamlin Mount Mica crystal, 371 Trumper, L.C.: thesis on measurement of refractive index by —violet-blue, resembling tanzanite, 179 reflectivity, 97 Trade fairs, 118 Tsavorite: {see also Garnet) well-formed crystals from Trade Liaison Committee Meetings: 449, 513 Tanzania, 307 Treasure Chest gem tester, 306 Turquoise: deposits in Australia, 440 Treated stones: —imitation {see Synthetic and simulated gemstones) —agate with dendrites engraved on base, 460 —in North America, 242 —amethyst: conversion of citrine to, by irradiation, 111; heat treated, converted to citrine, 42, 111; growth structures in, Uniaxial gemstones {see Optical uniaxial gemstones) 481 Uraninite: associated with rose quartz, 274 —ancient texts describing: 'Natural History' by Pliny, 399, —as an inclusion: in sapphire, 73, 74, 372; in taaffeite, 239 401, 402; Papyrus Graecus Holmiensis, 399, 400 Ureyite: discoverer of terrestrial, 226 —Aqua Aura treatment: gold-film bluing of faceted gems, 309; Uruguay: growth structures in amethyst from, 480 of quartz, 444 USA: —aquamarine, heat treatment, history of 403 —amethyst from: in Connecticut, sceptre amethyst crystals, —chalcedony, artificially induced dendritic inclusions in, 460 239; in eastern United States, 242; in Maine and New —citrine: conversion of amethyst to, by heating, 42, 111; Hampshire, 104 irradiated, converted to amethyst, 111 —axinite from Thornberry Mountain, Coarsegold, California, —corundum: clear and opaque as raw material for heat-treated 241 sapphires, 179; diffusion-treated, 442; geuda, anomalous —azurite from Bisbee, Arizona, 441 550 JGemm., 1991,22

—beryl, red, from the Wah Wah mountains, Utah, 378, 445 —COOK, R.B., Amethyst occurrences of the eastern United —diamonds from: in Murfreeesboro, Arkansas, 374; recent States, 242 discoveries of large crystals in Trinity County, California, Whiterite associated with rose quartz, 282 309 WIERSEMA, B., Spotlight on Scripps, 114 —diopside, transparent green, from New York, 376 WIGHT, W., Kamieni szlachetne i ozdobne Kanady, 378 —hodgkinsonite, cut pink, from Franklin Furnace, New WILDMAN, M., {see Hanano, J., et al.) Jersey, 369 WILKE, H.-J., Die mineralogische Sammlung des Natural —hot rocks from Hawaii, 242 History Museum in London, 3 78 —kimberlite pipes in Michigan, 308 —POPOVA, E.E., Das Mineralogische Museum des —morganite from: in California, 376; in Maine, 376 Leningrader Bergbau-Institute, 447 —opal: chatoyant, from Idaho, 443; fire, from Louisiana, 376 WILSON, A.F., The use of isotopes in exploration for —pearls from: freshwater from Texas, 306; use in adornment gemstones, 114 by native Americans, 332 WILSON, W.E., {see also Souza, R.A., et al) —pyrope from Arizona, forsterite inclusions in, 374 —Goldschmidt's world mineral locality index, 183 —quartz from: in Arizona, smoky quartz, 377; rose quartz, 42 —What's new in minerals ?, 242, 378 —sapphire from Montana, 239, 439 WOLLAERT, E., VOCHTEN, R., VAN LANDUYT, J., —serendibite from Johnsburg, New York, 139 Characterisation of gem opal and inferior opal qualities by —sunstone from Idaho, 239 means of electronmicroscopy, 378 —tourmaline from: in Himalaya Mine, California, 42; in Wong, Mrs C, Obituary, 246 Mount Mica mine, Maine, 110 WOODHEAD, J.A., ROSSMAN, G.R., SILVER, L.T., The USSR: metamictization of zircon: radiation dose dependent —diamond: as inclusions in garnets in metamorphic rocks structural characteristics, 447 from Kazakhstan, 377; new find at Archangelsk, 308 WOODRUFF, R.E., FRITSCH, E., Blue pectolite from the —emerald: from the Ural Mountains, chemical analysis of, Dominican Republic, 242 171; lattice parameters, 172, 173, 177; thermal World map of gem deposits, 119 conductance, 234; typomorphic features, 238 WYKOFF, G.L., Beyond the glitter, 383 —ruby from: in Azov, 180; in Pamir Mountains, 373 —scapolite, gem crystals of, from the Tarakuloma Ridge, Xenotime: associated with ruby, 487, 489 Pamir Mountains, 113 X-radiography, use of in identification and study of pearls, 10, —spinel from: gem crystal from the Pamir Mountains, 110; in 15 Lake Baikal area, in marble, 376 X-ray analysis, energy dispersive: —synthetics from: alexandrite, 377; ruby, new type, 239; —of hematite: 205, 206; spectrum, 205 spinel, flux-grown red, 178, 180, 300 —of pyrope-almandine, 239 X-ray diffractometer, single-crystal identification of gemstones Valta, Mr A., Obituary, 504 by, 112 VAN LANDUYT, J., {see Wollaert, E., et al) X-ray fluorescence, energy dispersive: analysis of Russian flux- Vasar synthetics {see Synthetic and simulated gemstones) grown red spinel, 303 Vesuvianite crystals from Jeffrey Mine, Quebec, 447 X-ray powder diffraction: examination of black, opaque, cut Vietnam: ruby from, 308, 442 stones, 132, 133 —sapphire and ruby mines re-opening in, 180 —of hematite, 205, 206 VILARDELL, D., {see Arjalaguer, I.) —measurement of lattice parameters in emerald, 172, 173, Visual optics, 108 177 Vivianite associated with rose quartz, 282 —of spessartine inclusion in topaz, 367 VOCHTEN, R., {see Wollaert, E., et al.) X-ray, proton-induced emission: analysis of Burmese and Thai VOOKLES, L.L., {see Levine, G.) rubies, 446 —impact of on gemmology, 237 WADE, K., FUJINUKI, T., (Factors controlling amounts of —study of natural and synthetic rubies, 446 minor elements in pearls), 377 X-ray spectroscopy, impact of on gemmology, 237 WAGNER, L., {see Scovill, J.A.) XU, M.Y., JAIN, H., NOTIS, M.R., Electrical properties of Wales: the Dolaucothi gold mines, 379 opal, 114 —Welsh minerals, 379 WALTER, D.R., Australian gems: malachite, 242 YAMAOKA, S., {see Miyamoto, M., et al) WANG, F.Q., {see also Guo, J.F.) YEUNG, I., Treasures of Peinan culture found in Taiwan dig, —GUO, J., Chicken-blood stone from China, 114 447 WANNEMACHER, J., {see Bente, K., et al) Yttrium aluminium gallium garnet {see Synthetic and WARD, F., Emeralds, 242 simulated gemstones) —The search for jade, 447 YURKIEWICZ, P.G., {see Hanano, J., et al) Wardite associated with rose quartz, 282, 283 WATT, J.C.Y., Neolithic jade carving in China, 242 Zaire: Mashamba West mine, cobaltian calcite and cuprite WEERTH, A., Neue Mineralfunde aus den berühmten from, 374 pakistanischen Edelsteinpegmatiten, 377 —star sapphire from, 372 WEIBEL, M., {see also Hänni, H.A.) Zambia: aquamarine from Miku, 411 —GRAESER, S., OBERHOLZER, W.F., STALDER, H.-A., —emeralds from: infrared spectrum, 218; in Morrua, chemical GABRIEL, W., Die Mineralien der Schweiz, 383 analysis of, 172, lattice parameters, 172, 173, 177; as raw WEISS, S., {see also Höchleitner, R.) material for Pool synthetic emerald, 41 —Eisenhaltiger gelber Orthoklas - ein wiederentdekter —imitation emerald crystal from, 239, 373 Edelstein aus Madagaskar, 447 ZECCHINI, P., {see Martin, F., et al) WELBOURN, CM., {see Frank, F.C., et al.) ZEITNER, J.C., Eternal sky, 242 Wernerite {see Scapolite) —Obsidian, 242 WHITE, J.S., {see also Souza, R.A., et al) —Thunder Bay, 114 JGemm., 1991,22 521

ZHILIANG, N., Preface to collected illustrated works on —from Burma, 307 ancient jade, 378 —cat's-eye effect in heat-treated, 107 Zimbabwe: —colour filter tests: on blue, 212; on yellow, 213 —emeralds from: geological occurrences, 265, 266, 267, 269, —crystal forms of, 468 geotectonic setting, 264, 265, infrared spectrum, 218 —diamond inclusions in, 377 optical data, 271; in Machingwe, gemmological properties, —as an inclusion: in garnet, 377; in ruby, 87; in sapphire, 70, 270, 271, inclusions, 272, new discovery at, 264, 267; in 73, 74, 86, 179, 201, 372; in star rhodolite (?), 16 Sandawana, chemical analysis, 270, high Cr content, 416 —metamict green with laminated structure, 239 —euclase from, sapphire blue, 108 —metamictization of, 447 —greenstone belts in: geology of, 264, 265, 266; emeralds in, —from Nigeria: absorption spectrum, 200; chemical analysis, 266, 267, 268 201; colour, 200; crystals, rounding of, 200; in decomposed —Rhodesian craton, geological map of southern part, 266 alakali basalt, 199, 200, 201 — ruby in metamorphic rock, 373 —from Sri Lanka: cat's-eye effect in heat-treated, 107; green, Zircon: in alkali basalt, 199, 200, 201 180; metamict green, with unusual iridescence, 239 —associated with rose quartz, 274; with ruby, 487, 489 —from Tanzania, 239 —from Australia: gemmological properties of, low uranium or Zoisite: green, bearing ruby crystals, 114 thorium content of, 178 ZWAAN, P.C., (see Kanis, J., et al.) THE GEM DIAMOND DIPLOMA

GAGTL have brought together the finest minds in the world of diamonds to produce the most comprehensive Gem Diamond home study course available. The course acknowledges the professionalism of the international diamond market and includes every aspect of gem diamond you will ever need to know.

Following an examination in theoretical knowledge and practical application - including grading of polished and rough, you may gain the Gem Diamond Diploma and be entitled to the special Diamond Membership of GAGTL With DGA after your name your professionalism will be obvious for all to see

For further information please contact Louise Macdougall on 071-404 3334, or complete the reply form below.

I 1 I To GAGTL Education Department, 27 Greville Street, London EC1N 8SU I | Please send me details and an application form for the Gem Diamond Course. |

I Name: .

, Address: ,

Telephone: JG 4/92 L- Copyright © 1991 The Gemmological Association and Gem Testing Laboratory of Great Britain Registered Office: Palladium House, 1-4 Argyll Street, London WI V lAD

ISSN: 0022-1252

Produced by Green Belt Studios: Printed by Quadrant Offset, Hertford, England.