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| and Liddicoatitic Tourmalines ANJANABONOINA DISTRICT, MADAGASCAR T he tourmaline database, like that...Madagascar, as the calcium analogue of the well-known gem and specimen species elbaite (Dunn, Appleman, and...those cut across the c-axis, at major mineral and gem shows. Consequently, because of its great collector...highlands of the Vakinankaratra region, Antananarivo Province, near Antsirabe and south of Betafo, near the...perpendicular to the c-axis, is from the Anjanabonoina district, Madagascar. Trinity Minerals specimen, John Veevaert |
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| JOURNAL OF THE GEMOLOGICAL INSTITUTE OF AMERICA Sri Lanka: Where Tradition and Technology Meet Characteristics...Tomorrow 173 Duncan Pay FEATURE ARTICLES 174 Sri Lanka: Expedition to the Island of Jewels Andrew Lucas...Pedro Padua pg. 175 Offers a firsthand look at Sri Lanka’s mining, cutting, jewelry manufacturing, and...colored stones. 228 Nephrite Jade from Guangxi Province, China Zuowei Yin, Cui Jiang, M. Santosh, Quanli...with flux synthetic ruby overgrowth pg. 243 244 Gem News International Aquamarine with unusually strong |
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| Branch: M. P. Gayton, F.G.A. South Yorkshire & District Branch: 1. R. M. Lewis, F.G.A. Examiners: B. W...many others, I owe all such knowledge of gems and gem materials as I possess—apart, in my case, from such...matters more complicated the actual weights used by gem merchants with their balances were numbered 1000...appeared in the early years of the century are The Gem Cutter's Craft by L. Claremont (London, 1906), which...was my standby when I first started work in the Gem Testing Laboratory, but one had to wait until 1940 |
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| Edelseifen um Ratnapura . . . . . . . . . . 22 Lageskizze der Edelsteinfelder in der Provinz Sabaragamuwa Ceylons...Polonnaruwa • Kandy Nuwara Eliya Adam's Peak Ratnapura • .Pelmadulla • Rakwana Malara Karte von Ceylon...altorientalisches Dichterwort die paradiesische Insel Lanka an der Siidspitze Indiens. Es hat bis heute seine...von Edelsteinen wie gerade Ceylon.Bereits in den Lanka-Sagen finden sich manche Hinweise auf Ceylons Edelsteinreichtum...ausser Gewiirzen auch Perlen und edle Steine aus Lanka, wie Ceylon im Altertum hiess, exportiert wiirden |
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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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| 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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| 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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| reputation? It’s the most reliable, authentic, dependable gem institute in the world. People know that, especially...Sapphire from the Tan Huong–Truc Lau Area, Yen Bai Province, Northern Vietnam Nguyen Ngoc Khoi, Chakkaphan...Nhung Although not as well known as the Luc Yen district, this area is an important source of ruby and...Green sapphires with different chromophores 234 Gem News International Greenish brown diamonds with color...Freshwater cultured pearl beads • Quartz with spessartine inclusions • Pink cat’s-eye quartz • Rhodochrosite |
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| Gemesis CVD synthetic diamond New sapphires from Sri Lanka Cultured pearls from Micronesia VOLUME 48 NO...reputation? It’s the most reliable, authentic, dependable gem institute in the world. People know that, especially...Sapphires from Thammannawa, Kataragama Area, Sri Lanka Pannipitiye G. R. Dharmaratne, H. M. Ranjith Premasiri...sapphires, the object of a recent gem rush in southeastern Sri Lanka, possess good transparency and a...research efforts have led to dramatic progress in gem-quality CVD synthesis and post-growth treatment. |
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| structure Properties of crystals Gem crystals 19 19 20 20 21 22 32 33 3 Gem testing Hardness Gemstones and...Specific gravity 36 37 56 4 Recent developments in gem testing Thermal conductivity Measurement of refractive...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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| North-West Branch: S. Hill, F.G.A. South Yurkshire & District Branch: J. L Reynolds, F.G.A. Examiners: E. A...Phil., F.G.A.†and V.K. Din, C.Chem., M.R.S.C.†*Gem Testing Laboratory of Great Britain, 27 Greville...with lavas and there is only one major volcanic province - that of Thailand and Kampuchea (Cambodia) -...the Laboratory - 8 Kenneth Scarratt, F.G.A. The Gem Testing Laboratory of Great Britain, 27 Greville...rare gemstone but also in the presentation of any gem material, it is a pleasure to see a diamond fashioned |
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| provides a comprehensive examination of gems and gem materials including discussion of their properties...and popularity in different cultures. The Museum's gem collection, itself the stuff of legends, is described...factors important in determining the quality of each gem and spells out the possible confusions in gemstone...TO THOSE WHO HAVE HELPED CREATE THE MINERAL AND GEM COLLECTIONS. Those whose donations are featured...Tourmaline PAGE 88 18 Zircon& What1a Rridot Gem? PAGE PAGE 22 Corundum Diamond PAGE PAGE 44 |
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| assemblage such as the zeolites from India, or high gem quality such as the rubies from Burma, or some significantly...notable example in this category is the Nuristan District of Afghanistan, which over the past 10 years has...has produced some of the most extraordinary gem minerals ever found. The majority of this volume is based...Saijo, Iyo Province, Ehime Prefecture, Island of Shikoku Ashio Mine, Shimotsuke Province, Tochigi Prefecture...Arakawa Mines, Ugo Province, Akita Prefecture, Honshu The Obira Mine, Bungo Province, Oita Prefecture, |
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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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| the authors 4 Iolite (cordierite) 55 Is it a gem? 5 Andalusite, Fibrolite (sillimanite) Finding...Further reading and credits 73 Tanzanite 54 Gem deposits of the world 74 Taaffeite 54 Index ...qualities of beauty, rarity and about the individual gem species. The main durability, which are determined...are described, together with identifying gems. Gem mineral formation is notes on items of particular...outreach and (GAGTL) and the British examiner for the gem testing services. Prior to this post die was European |
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| region encompasses ·what may be the world's richest gem deposits, and is explored in depth in this pioneering...clearly among the world's richest areas, akin to Sri Lanka and Brazil, which interestingly, share a similar...It is rapidly becoming of major importance to the gem world. East Africa is home to two of the world's...Africa 3 Geological Overview of East Africa's Gem Fields 3 The Tanzanian Shield 6 The Mozambique Belt...Longido, Northern Province, Tanzania 28 Ruby and Sapphire from Umba, Tanga Province, Tanzania 32 Sapphire |
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| Ian Ballour) Contents INTRODUCTION GEM IDENTIFIER Main gem groups Other gemstones Natural glasses...have tried to recognize these fakes. Synthetic gem- and optical properties by which they may be identified...on the scale grains that make them the toughest gem¬ but was in turn scratched by those beneath stones...be un¬ (9) and talc (1). For use in jewellery, gem¬ even, hackly (jagged) or conchoidal (shell - stones...hardness less than 7 are therefore likely common, gem-quality material may be to become scratched with |
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| carats from Burma. gemstones. Tanzania. Rare Sri Lankan orange sapphire of 57.26 carats. Emerald...illustrated. The section ends with a brief account of gem cutting. The most popular gemstones are described...final section of the book is concerned with how gem minerals form, where they are found and how they...are identified, and a selected index to the main gem species, technical terms and important topics such...Geological Museum in London. The collection consists of gem minerals in both a natural state and cut as exquisite |
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| 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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| 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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| 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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| E. Post, Geologist, Curator-in-Charge, National Gem and Mineral Collection, National Museum of Natural...at www.dk.com CONTENTS INTRODUCTION What is a Gem? 8 How Gems Form 10 Crystals 12 Classifying...Cutting Gems 28 Polishing and Engraving Gems 30 Gem Enhancement 32 Synthetic Gems 34 History and... 214 Index 218 Acknowledgments 223 HOW THE GEM PROFILES WORK main section ; profile information...viene INTRODUCTION ‘ag yet Gay x 2 WHAT IS A GEM? Gems are generally defined as precious or semiprecious |
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| of China 14 The Changma Diamond District, Mengyin, Shandong Province, China Peter C. Keller a n d W...Fujian Province, China Alice s. Keller and Peter C. Keller 46 Gem Trade Lab Notes 54 Gem News 57...orticles i n this special issue discuss the many gem materials that are currently found i n the People's...resources of this vast and geologically complex region. Gem resources, in particular, have been a low priority...Chinese in determining and exploiting the country's gem wealth. One consequence of this new interest in gems |
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| TREASURES The IN THE SMITHSONIAN Gem Collection Paul E. Desautels ;".'*" - • * « . ^- - ...: »•• * . The Gem Collection TREASURES The IN THE SMITHSONIAN Gem Collection Paul E. Desautels...Paul E Treasures in the Smithsonian: the Gems. gem collection. Smithsonian Institution. Smithsonian...One of the more important gifts to the Smithsonian gem collection in recent years is the 68-carat Victoria-Transvaal...champagne-colored gem was discovered in Africa in 1951. CONTENTS I. II. THE NATIONAL GEM COLLECTION THE |
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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 |
