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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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| Concentrated by Surface Waters: 1 5 The Gem Gravels of Sri Lanka 2. Gemstones Formed from Surface Water:...Gemstones of Igneous-Hydrothermal Origin 3. Hydrothermal Gem Deposits: 35 39 The Emerald Deposits of Colombia...Colombia 4. Gemstones Formed in Pegmatites: 57 Gem Pegmatites of Minas Gerais, Brazil 5. Gemstones Formed...Gemstones Formed at Great Depths 8. Mantle Thrust Sheet Gem Deposits: 115 119 The Zabargad Island, Egypt, Peridot... Western Australia Index 141 FOREWORD Each gem deposit-whether of primary origin in the parent rocks; |
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| Concentrated by Surface Waters: 1 5 The Gem Gravels of Sri Lanka 2. Gemstones Formed from Surface Water:...Gemstones of Igneous-Hydrothermal Origin 3. Hydrothermal Gem Deposits: 35 39 The Emerald Deposits of Colombia...Colombia 4. Gemstones Formed in Pegmatites: 57 Gem Pegmatites of Minas Gerais, Brazil 5. Gemstones Formed...Gemstones Formed at Great Depths 8. Mantle Thrust Sheet Gem Deposits: 115 119 The Zabargad Island, Egypt, Peridot... Western Australia Index 141 FOREWORD Each gem deposit-whether of primary origin in the parent rocks; |
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| 2 TABLE OF CONTENTS FEATURE ARTICLES 62 Sri Lanka: The Gem Island Peter C. Zwnan The Identification...Illumination: A Controllable System of Lighting for Gem Microscopy John I. Koivula 8 7 Radioactive Irradiated...Greenland Aage Jensen and Ole V. Petersen Carving Gem-Quality Opal Theodore Grussing Two Notable Color-Change...REGULAR FEATURES Gem Trade Lab Notes Editorial Forum Gemological Abstracts Book Reviews Gem News , A B O...a n y fine gemstones found on the island o f Sri Lanka, the subject of Peter Zwaan's article i n this |
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| Dimensions in the captions refer to the entire gem or mineral; however, in some cases only a portion...A CHANGING PLANET 11 Vanadinite, San Carlos district, Chihuahua, Mexico * 8 x 4 x 2 cm Mineral Species...can be as valuable as the richly colored stones. Gem cutters bring out the inner beauty of gems by creating...trick with light. Facets allow light to enter the gem; once inside, the light bounces off its other angled...Africa and Canada « 2.00 ct and 3.06 ct leaves the gem, similar to what happens when you pass light through |
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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 |
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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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| 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...sapphire • Quarterly Crystal: Orpiment in barite 118 Gem News International Tucson 2019 • Boulder opal mining...Responsibly sourced gemstones • The Chinese and Japanese gem markets • Unusual and vibrant gems • Jeff Hapeman |
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| Colombian Emeralds Ron Ringsmd The Elahera Gem Field in Central Sri Lanka Mahinda Gunawardene and Mahinda S....Nassau REGULAR FEATURES Editorial Forum Gem Trade Lab Notes Gem News Gemological Abstracts Book Reviews...LaFayette, Indiana Sallie Morton San lose, CA Editor, Gem Trade Lab Notes C . W. Fryer Editor, Gemological...Jeffrey M. Burbank Contributing Editor and Editor, Gem News John I. Koivula Production Assistant Patricia...COLOMBIAN EMERALDS By Ron Ringsrud The Muzo emerald district, i n Boyacd, Colombia, contains several mines |
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| r· Butterworths Gem Books Edited by Peter G. Read Amber Helen Fraquet Beryl John Sinkankas and Peter... Huddlestone Topaz D. B. Hoover Butterworths Gem Books Corundum Richard W. Hughes Executive Vice...Corundum/Richard W. Hughes. p. cm.-{Butterworths gem books) Bibliography: p. Includes index ISB!'i 0-7506-1006-9:... Major sources: Burma, Thailand, Cambodia, Sri Lanka, India, Australia, Kenya, Tanzania, Montana and...we have books on gem deposits, the lapidary arts, carved gems, gem treatments, gem identification, history |
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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 |
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| of Great Britain Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street...Koivula Gemological Institute of America (GIA), GIA Gem Trade Laboratory, 5355 Armada Drive, Carlsbad, California...most noticeable internal features visible in some gem-quality synthetic moissanite. These channel inclusions...natural etch channels seen on rare occasions in some gem diamonds. The origin of the channels in synthetic...both diamond and cubic zirconia, CZ). Like many gem materials, synthetic moissanite has its own internal |
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| comparatively large transparent crystals such as those of gem quality minerals) uniaxial minerals will have the...table) play an important part in the colouration of gem minerals although they do not colour anything like...the materials of the case in which they are kept. Gem quality minerals - and there are relatively few of...material is in gravel form (with luck the gem gravels of Sri Lanka) sieve it into a sink, screen it, and...kept dry and away from anything containing sulphur. Gem materials which have had their colour improved may |
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| Penglai, Hainan Island, China W h g Furui 161 A Gem-Quality Iridescent Orthoamphibole from Wyoming R...and fohn I. Koivula REGULAR FEATURES Gem Trade Lab Notes Gem News Gemological Abstracts Book Reviews...Telephone: ( 8 0 0 ) 4 2 1-7250 x 2 0 1 Editor, Gem Trade Lab Notes C, W Fryer Editor, Gemological Abstracts...Misiorowski Contributing Editor, John I. Koivula Editors, Gem News lohn I. Koivula Robert C. Kammerling PRODUCTION...Gems e) Gemology, contact the Association of Japan Gem Trust, Okachin~achi Cy Bldg, 5-15-14 Ucno, Taito-ku |
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| Association and Gem Testing Laboratory of Great Britain Gemmological Association and Gem Testing Laboratory...Because tube-like structures that extend into the gem-quality ruby sectors are almost colourless, and the...was supported by © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 135^4565...been only rarely applied to the characterization of gem materials. Using trapiche rubies as an example, the...understand various effects of chemical zoning within gem materials. Possible applications of of element mapping |
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| 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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| Franks, B.Sc., Ph.D., F.G.A. South Yorkshire & District Branch: J. L Platts, F.G.A. Examiners: E. A. Jobbins...INTENSIVE YELLOW TSILAISITE (MANGANESE TOURMALINE) OF GEM QUALITY FROM ZAMBIA By Dr KARL SCHMETZER* and Prof...†Idar-Oberstein, West Germany ABSTRACT Transparent gem tourmalines with an intensive yellow coloration from...members of the series dravite-uvite. In both groups of gem tourmalines small amounts of iron, i.e., small percentages... In general, manganesecontaining tourmalines of gem quality were determined as elbaites with only small |
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| cultured pearls. pg. 22 73 Serendibite from Sri Lanka Karl Schmetzer, George Bosshart, Heinz-Jürgen... A characterization of this rare gem material from Sri Lanka. Gem Trade Lab Notes • Color grade vs....natural pearls • Spinel in heat-treated sapphire 86 Gem News International • Special report: New corundum...CA 92008 (760) 603-4504 akeller@gia.edu Editors, Gem Trade Lab Notes Thomas M. Moses, Ilene Reinitz, Shane...Shane F. McClure, and Mary L. Johnson Editor, Gem News International Brendan M. Laurs Senior Editor |
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| if not created, a rapid growth in the hobbies of gem cutting, jewelry making, and mineral collecting....same time people in the jewelry industry and the gem trade have recognized the need for greater technical...description of a great collection, a single gem material, gem cutting, or jewelry mak- ing. In addition...chapter, dealing with the genesis and occurrence of gem minerals, is followed by chapters on the chemical...in their determination. Brief chapters deal with gem inclusions and imperfections, synthesis, imitation |
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| same time people in the jewelry industry and the gem trade have recognized the need for greater technical...description of a great collection, a single gem material, gem cutting, or jewelry making. In addition many...chapter, dealing with the genesis and occurrence of gem minerals, is followed by chapters on the chemical...in their determination. Brief chapters deal with gem inclusions and imperfections, synthesis, imitation...subject and a gem index to facilitate obtaining con1monly sought information; the name in the gem index is |
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| been named the featured mineral at the 1995 Tucson Gem & Mineral Show. MICHAEL A. WISE Department of Mineral...National Museum of Natural History TOPAZ IS THE STATE GEM of Texas and Utah; however, it is best known to the...its unique attributes is that, unlike many other gem minerals, topaz may occur in crystals large enough...of Cornwall, England, and France; 9. Erzgebirge district, Saxony, Germany; 10. Volyn and Kiev pegmatite...Gilgit pegmatite district and Katlang, Pakistan; 13. Tin granites of Jos plateau district, Nigeria; 14. |
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| culture, derives its name from the saltmining district of Hallstatt in Upper Austria, where many prehistoric...The sedimentary rocks 1 RESIDUAL ROCKS grit, gravels (in part), weathered clay, laterite, bauxite 2...than 2 mm.): grits and breccias (angular grains), gravels, conglomerates (rounded grains), moraines and tillites...have been concentrated by secondary enrichment. Gravels are partly residual formations and partly elastic...by rivers; tidal action forms gravel beaches. Gravels may be loose or recemenced, and they are formed |
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| Association and Gem Testing Laboratory of Great Britain Gemmological Association and Gem Testing Laboratory...3334 l Fax: +44 (0)20 7404 8843 e-mail: information@gem-a.info l Website: www.gem-a.info President: E A Jobbins...diamond: genetic information and implications for the gem industry Part I: The main types of internal growth...individual stones during gem production. Keywords: cathodoluminescence, diamond, gem industry, internal structure...diamond as anomalous © Gemmological Association and Gem Testing Laboratory of Great Britain birefringence |
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| run verticall y or horizontally righ t across the gem surface. Onyx is very popu lar in pe n da n t s an...have been the name of a town in ancient Egypt. A GEM AND A ROCK I I Most alabaster is defined as the...be artificially ""tJ Right: Although the term 'gem' is most commonly associated with the precious mountings...alabaster from Volterra, near Pisa (Italy). This gem material is basically the mineral gypsum. Although...now exhausted, but the gem can still be found in small quantities in Sri Lanka, Burma and Brazil. Alexandrite's |
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| BUTTERWORTH-HEINEMANN GEM BOOKS DB ♦ ◊ HOOVER ♦ Butterworth-Heinemann Gem Books Edited by Peter...Nassau Gem Testing, 10th edn B. W. Anderson, revised by E. A. Jobbins Butterworth-Heinemann Gem Books...Data Hoover, D. B. Topaz. - (Butterworth-Heinemann Gem Books Series) I. Title II. Series 553.8 ISBN 0 7506...of South Africa 189 Saudi Arabia 190 Spain 190 Sri Lanka 190 Sweden 191 Thailand 192 Turkey 192 United...Read asked if I would write one of Butterworth's Gem Books, I chose topaz as the subject, because of my |
