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| inclusions or these cannot be seen because the host gem is too opaque. The brownish opal termed hyalite,...KennethScarratt, Kenneth Scarratt, F.G.A. F.G.A. The Gem Gem Testing Testing Laboratory Laboratory of of Great...Laboratory's name that has changed, firstly from 'The Gem Testing Laboratory of the London Chamber of of Commerce...Commerce and Industry' and then to 'The British Gem Testing Laboratory of the London Chamber ofCommerce...The The Laboratory Laboratory is now known as 'The Gem Testing Laboratory of of Great Britain'.. Britain' |
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| Tribute to Robert M. Shipley, Jr. The Chanthaburi-Trat Gem Field, Thailand Peter C. Keller 197 Gemstones with...Alexandrite Effect E. Giibelin and K. Schmetzer 204 Gem-Quality Grossular Garnets D. Vincent Manson and Carol...Crystal: The Van Pelt Collection John Sinkankcis 221 Gem-Quality Friedelite from the Kalahari Manganese Field...REGULAR FEATURES Gem Trade Lab Notes Editorial Forum Gemological Abstracts Book Reviews Gem News Index to...Liddicoat, Jr. Associate Editor Peter C. Keller Editor, Gem Trade Lab Notes Chuck Fryer Editor, Gemological Abstracts |
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| FEATURE ARTICLES 2 A New Method for Determining Gem Tourmaline Species by LA-ICP-MS Ziyin Sun, Aaron...a simplified but comprehensive classification of gem tourmaline species based on quantitative measurement...Zircon Inclusions in Sapphires from Ratnapura and Balangoda (Sri Lanka) and Implications for Geographic...Chatoyant quartz/tourmaline doublet • Faceted gahnospinel • Glass bangles resembling jade • Faceted parisite...sapphire • Quarterly Crystal: Orpiment in barite 118 Gem News International Tucson 2019 • Boulder opal mining |
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| Australia: Canadian Gemmological Association: Rhodesian Gem and Mineral Society. THE JOURNAL OF GEMMOLOGY A...BRITAIN Vol. X I V N o . 8 O C T O B E R 1975 ON GEM ELBAITE FROM NEWRY, MAINE, U.S.A. By PETE J. DUNN...significant find of gem quality elbaite (lithium tourmaline) was made at the Dunton gem mine, Newry, Maine...facet-grade. Some gem pockets had been found in recent years, but the yield of gem material was small...however, and only serves to give the beautiful red gem material a crackled green coat! The thin outer green |
 | | Journal (issue) |
| Sapphires from Sri Lanka Kcirl Scl~metzerand Olaf Medenbach REGULAR FEATURES 112 120 124 131 Gem Trade Lab...Lab Notes Gem News Gemological Abstracts Book Reviews ABOUT THE COVER: The extraordinary play-of-color...Diffraction, one of the less common causes of color in gem materials, is described in this issue in the third...extensive listing of the known origins o f color in gem materials. The opal, from the Ditto 3 Harold &> Collection...pit. Virtually all o f the diamonds recovered are gem quality, although most are relatively small, averaging |
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| E YE WI TNES S HA N D B O O KS GEM STONES The visual guide to more than 130 gemstone varieties...org/details/gemstoneseyewitnOOcall EYEWITNESS HANDBOOKS GEM STONES E YE WI TNESS HANDBOOKS GEMSTONES Cally...varieties are found and fashions change. Over 130 gem species, including some exceptionally rare stones...why the species entries in this its book show the gem rough, natural state, perhaps embedded in still...they can be appreciated by anyone, from the amateur gem-spotter to the enthusiast who enjoys their beauty |
 | | Journal (issue) |
| CVD synthetic diamond | Updated CIBJO Blue Books | Gem laboratory newsletters | New JVC Essential Guides...Photomicrography using a smartphone camera 24 Gem Notes Colourless cat’s-eye apatite | Prismatic Ethiopian...Excursions 69 From the Archives 73 Conferences 78 Gem-A Notices 80 New Media 84 Literature of Interest...Brendan M. Laurs brendan.laurs@gem-a.com Mary A. Burland mary.burland@gem-a.com Executive Editor Editor...Harding Marketing Consultant Ya’akov Almor bizdev@gem-a.com Assistant Editor Michael J. O’Donoghue Associate |
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| Properties of crystals Gem crystals 18 19 19 20 20 21 22 32 33 3 3.1 3.2 3.3 Gem testing Hardness Gemstones...56 4 4.1 4.2 4.3 4.4 4.5 Recent developments in gem testing 59 59 60 61 64 65 Thermal conductivity...understandably and rightly, with the science of gem testing and have covered that area very well. Details...entirely new gem mineral species have been found in the last few years; tanzanite, appearing on the gem market...with no gem potential whatever. It is not likely that many entirely new mineral species with gem application |
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| EDITION AREM, PH.D., FG.A. gem gemologists, 1977, jewelers, and gem collectors, dealers have relied...INTRODUCTION What / Gem? a / Scope of This Book / Is The Nature Gems of GEM SECTION 1 2 GEMSTONES...Rock Classification Gem Scarcity Intrusive Crystal 6 Growth Synthetic Gem 9 / Gemstones SOURCES...dealers are aware of the growing value of exotic gem species; the list of known taaffeites has thus grown...greater monetary reward than are the tists who gem scien- build detection equipment. Inevitably, a |
 | | Book |
| Marvel over India's maharajahs, the world's greatest gem collectors, for whom no price was too great. Explore...star ruby on public display. A product of Sri Lanka's gem gravels, today it resides at the Smithsonian in...301 has yet to be surpassed for ruby. Today the gem is said to be 1n the personal collection of one of...of pure celestial blue Set i11 a golden band; A gem that owes its beauty to No lapidary's art, But to...origin is uncertain, but probably emanates from Sri Lanka. Today it rests in New York's Amer1can Museum |
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| 1 2 The Geological Sources of Gems Crystalline Gem Materials 3 40 Part II 3 4 5 6 7 8 9 10 11 12 13...The Biological Gem Materials The Fashioning of Gemstones Value-Enhanced Gemstones and Gem Materials 292...library for virtually all sources. Derivations of gem and mineral names are not given; they can be found...not now considered valid or current. While many gem collectors collect mineral specimens too, the text...text for the 1994 edition. In this new edition, the gem testing section has been omitted; this information |
 | | Book (edition) |
| to prepare a new edition of the Guide. Many new gem species have been added to the collections in recent...wherever possible. In a developing world the names of gem-producing countries may change rapidly, but many...in brackets) arc shown in the following list: Sri Lanka (Ceylon), Malagasy Republic (Madagascar), Kampuchea...minerals which are used for orn amental purposes the gem minerals are arranged in a series of exhibits in...topaz, or zircon, which is in vogue; the favoured gem consequently rises in value until some new whim relegates |
 | | Journal (article/letter/editorial) |
| area. Each cut stone is 5 mm across. R. G. Weber (Gem Studies) photo. Figure 2. The Kingsley Sapphire,...000-mile (3,200-kilometer) corridor, myriads of small gem pockets are dispersed in the underlying crustal and...sometimes ruby, the gem varieties of the mineral corundum. Along with other gem minerals such as zircon...of gascharged molten basalt. Fragments from the gem pockets, Dr. F. Lin Sutherland is an adjunct professor...flowing lava. The durable and chemically resistant gem minerals, although corroded by the hot fluids, remain |
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| substitute cannot fail to bring further into disrepute a gem material which has been prized from ancient until...control, it has only recently impinged on the world of gem materials in the form of attractively coloured pieces...least emphasize the need for eternal vigilance in gem-testing in these tricky times. Synthetic Powellite...Mohs' scale) it is hardly likely to find favour as a gem substitute. T h e stone, weighing only 0-42 carats...r in fact of the "Gahnospinel" series which we discovered in the Ceylon gem gravels before the war. T |
 | | Book (edition) |
| Related titles The Diamond Formula A. Barnard Gem Testing, Tenth edition B.W. Anderson, Revised by...the last 170 years The essential qualities of a gem material Organic and inorganic gems 1 1 1 9 10 ...species and varieties The origin of gems Gem occurrences The major gem localities Mining techniques 11 11... Ruby Sapphire 221 222 18 Identifying organic gem materials and their simulants Natural pearls Cultured...volume, particularly in its emphasis on practical gem identification. I am also grateful to Vivian Watson |
 | | Journal (issue) |
| Australia: Canadian Gemmological Association: Rhodesian Gem and Mineral Society. THE JOURNAL OF GEMMOLOGY A...being the story of discoveries of new gem varieties and new gem minerals in which we were lucky enough...worthy of description. But the discovery of a new gem mineral is a rare event, for it implies that the... and tanzanite (1967) as instances of this. Gahnospinel O u r first investigation into stones which had...high-density blue spinels from samples of the Ceylon gem gravels. T h e rarity of these " a n o m a l o u s " |
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| minerals which are used for ornamental purposes the gem minerals are arranged in a series of exhibits in...topaz, or zircon, which is in vogue ; the favoured gem consequently rises in value until some new whim relegates... B. W. 1947. Gem Testing. 4th edit. Kraus, E. H. and C. B. Slawson. 1939. Gems and Gem Materials. 3rd...3rd edit. McCallien, W. J. 1937. Scottish Gem Stones. Smith, G. F. H. 1949. Gemstones. 10th ,edit. Spencer...polished plates of the minerals 6 to 9 and to rub the gem successively over them, beginning with number 6, |
 | | Journal (article/letter/editorial) |
| replacement, yet in the transparent varieties oI gem quality there is, as a rule, very little deviation...to certain transparent blue spinels from the gem gravels of Ceylon, the physical properties of which differ...authors at various times. TABLEI. Data for ordinary gem spinels. Colour. Locality. Carats. Crimson Pale...'zinc-spinel' would be held merely to denote gahnite. ' Gahnospinel' is tentatively suggested. It may be wondered |
 | | Journal (issue) |
| Branch: M. P. Gayton, F.G.A. South Yorkshire & District Branch: M. W. Eldridge, M.B., Ch.B., F.G.A. Examiners:...absorption in the visible region and most colourless gem quality diamonds contain substantial concentrations...using a hand spectroscope, Kenneth Scarratt of the Gem Testing Laboratory has observed (personal communication)...through Alec Farn of the London Chamber of Commerce Gem Testing Laboratory.I am also grateful to Mr Farn...Mohammed, K., 1981 (in preparation). Anderson, B. W., Gem Testing, 9th edn., p.211, London: Butterworths, 1980 |
 | | Journal (issue) |
| Robert E. Kane REGULAR FEATURES Gem Trade Lab Notes Editorial Forum Gem News Book Reviews Gemological Abstracts...ABOUT THE COVER: Many factors contribute to color in gem materials. This issue introduces the first of a three-part...causes, dispersed metal ions, in the color of many gem materials. For example, the yellow color in this...to indicate the man-made equivalent of a natural gem] differs from the classic definition (i.e., that...the use of any other term to describe manufactured gem equivalents. Marketing skills today are such that |
 | | Book |
| * * To my wife, who put up nobly with being a gem widow. A cknowledgements I am very grateful to the...Structure of Gemstones and their Imitations 35 The Gem Species 58 The Gemstone Industries 108 The Evolution...of these are capable of use as gems. While a few gem-forming minerals are relatively common, most are...annually. All this is, however, completely useless for gem pur¬ poses. The material is greyish and opaque; it...mined to win the gemstones. Even then most of the gem beryl will be wasted-either discarded as inferior |
 | | Book (edition) |
| Second edition Peter G. Read Garnet John D. Rouse Gem Testing, Tenth edition B . W . Anderson, Revised...ministrations as editor of their books in the Butterworths 'Gem Books' series!). In particular, I would like to express...study of the technical aspects of gemstones and gem materials. For well over 2000 years, philosophers...marked by the discovery and identification of a new gem species, green demantoid garnet. One of many disturbing...the same year the first successful synthesis of gem-quality emerald crystals was achieved by the French |
 | | Journal (issue) |
| Australia Canadian Gemmological Association Rhodesian Gem and Mineral Society THE JOURNAL OF GEMMOLOGY A...interest in the three speciments. (1) A "high" gahnospinel T h e first of the three stones was a small blue...zinc-rich blue spinels (for which our n a m e "gahnospinel" has been accepted) began in 1935, when T . W...zircons, the commonest constituent of the Ceylon gem gravels. This led to the discovery of a whole series...commercial value. But to us, as gemmologists to whom gahnospinel meant something "special", it was a profound |
 | | Journal (issue) |
| North-West Branch: S. Hill,: F.G.A. South Yorkshire & District Branch: J. L Reynolds, F.G.A. Examiners: E. A...Survey, Exhibition Road, London SW7 2DE, and †British Gem Testing Laboratory, 27 Greville Street, London EC1N...two stones (Fig. 1) were examined at the British Gem Testing Laboratory. Here it was agreed that whilst...stated that it occurred with topaz in the Taplejung District, Dhankuta Zone of eastern Nepal (see Fig. 2)....quality sapphire was also reported from the same district by A. Chikayama at the 19th International Gemmological |
| | Book |
| York To m y wife, who put up nobly with being a gem widow. A cknowledgements I am very grateful to the...Structure of Gemstones and their Imitations 35 The Gem Species 58 The Gemstone Industries 108 The Evolution...of these are capable of use as gems. While a few gem-forming minerals are relatively common, most are...annually. All this is, however, completely useless for gem purposes. The material is greyish and opaque; it...soil have to be mined to win the gem stones. Even then most of the gem beryl will be wasted - either discarded |
