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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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| Australia: Canadian Gemmological Association: Rhodesian Gem and Mineral Society. F.G.A. F.G.A. F.G.A. F.G.A...time came, the 'American Gem Society'. Very broadly speaking, the American Gem Society corresponds to the...had become attracted to the scientific study of gem materials. In some cases these 'outside' attachments...known as authors of the standard textbook Gems and Gem Materials. Other valuable long-term appointments...laboratory gemmologist as Director of the New York Gem Trade Laboratory. In 1952, at the age of 65, and |
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| © Tere crree! THE CLEVER GEM BUYER Sclaolalemcveliareln GAVIN LINSELL “She is more precious than...the main reason invariably is that a particular gem means something special to us: they represent a story...perceptions. Now in its second edition, The Clever Gem Buyer brings the reader not only the ‘gemmological’...in an absorbing and entertaining way, The Clever Gem Buyer’s second edition includes even more gemstone...mountain of gemstone rings’ in Thailand's Chanthaburi Province, an international centre for coloured gemstones |
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| Shandong Province, China fingfeng Guo, Fuquan Wang, and Gerry Yukoumelos Gem Trade Lab Notes Gem News Gemological...which a gcm is ,set i s often as important as the gem itself. Gold is the m o s t popular metul for fine...Hey1 Contributing Editor John I. Koivula Editors, Gem News John 1. Koivula Robert C. Kainmerling En~manuelFritsch...90404 Telephone: (800) 4 2 1-7250 x25 1 Editor, Gem Trade Lab Notes C. W. Fryer Subscriptions Gail Young...Gems & Gemology, contact the Association of Japan Gem Tnist, Okachiinachi Cy Bldg., 5-15-14 Ueno, Taito-ku |
 | | Report (issue) |
| —The Mineral Resources of the North-West Frontier Province. By A. L. Coulson. (Prioe As. 14 or la. 3d.) No...paper, “ Notes on Indian Precious Stones ”. Notes on Gem Stones have also been included in the Quinquennial...publications, also deals in addition with the use of the gem materials, their grades, overseas and Indian occurrences...in the above mentioned publications. Besides only gem materials of inorganic nature or minerals have been...Stones. CONTENTS. Paces. I F I. Introduction . Gem materials Imitation gems Synthetic gems II. Properties |
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| Fossils, Minerals and Gems, Crytsal Identifier, The Gem and Mineral Collection QUMSPGM Set in Futura Reproduced...provide strength to the unsurprisingly thought that gem weak. Crowns of kings and crystals held supernatural...a more complete and scientific understanding of gem crystals. They can most simply be defined as naturally... Today, many people still hold the belief that gem crystals in their = = wr =i Oo zZ rm wn Gemstone...dissipated. When the conditions are less ‘turbulent’, gem crystals will grow ceaaeos SI out of the solution |
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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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| 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 |
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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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| 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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| " PP ^ |5& V:.^ jV-. ^: V-. ■• 4* ' N^Sri dr., > A i'-.v ' .1 • , ...,, i ■'>1$ V -...through a stone. This distance factor is useful to gem cutters, who make light coloured stones thicker to...breakthrough, development work continued until a crystal of gem quality was produced in 1970. However, this process...diamonds \ n II \ K A scene from the which are not of gem quality are still being produced and play an important...RUBY Rubies have long been prized as a precious gem¬ The word diamond’ comes from the Greek 'Adamas' |
 | | Catalog/List |
| 2006 INDICOLITE TOURMALINE Brazil The blue variety of tourmaline, known in the trade as indicolite, is...15,000 2013 2014 HESSONITE GARNET Sri Lanka This an impressive gem of rich red hue with slight orange...2015 ORANGE GROSSULARITE GARNET Also known in the gem trade as Hessonite, this is a fine example of the...the local people. The present necklace contains 26 gem-quality beads of maw-sit-sit, a mineral which has...that are gem quality. Orthoclase can be found as a transparent colorless, champagne, or yellow gem resembling |
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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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| 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 |
 | | Report (issue) |
| this crown was not a ruby, but a tourmaline. The gem in this crown is now the oldest known important tourmaline...of Sri Lankan origin, are estimated to weigh more than 100 carats. The spinels are from Sri Lanka and... the rubies are from either Sri Lanka or Burma and the aquamarine is Sri Lankan. The tourmaline could...until its early eighteenth century arrival on the gem mar kets of Amsterdam, that tourmaline gained notice...from the Cingalese turamali (a mixed collection of gem rough), was introduced in Holland in 1703. The name |
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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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| 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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| 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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| 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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| Diamond Industries: 143,145. Acknowledgments: A & S Gem & Mineral Co., Lazare Kaplan International, Goldberg-Weiss...20 21 23 23 24 25 26 Introduction Gem History What Are Gems? Gem Criteria Origin of Gems Marketing of...Brilliancy Specific Gravity Luster and Fluorescence Gem Cutting 31 Gems and Gemstones 32 Diamond 44 Beryl...Irradiation 150 152 153 154 155 156 Gems as Investments Gem Testing Lapidary Hobby Jewelry Metals Popular Styles...is due to their unique properties. The colors of gem materials are among the richest and purest in nature |
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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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| 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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| To be sold without reserve 2015 ENAMEL, GOLD AND GEM-SET KALEIDESCOPE BY ANDREAS VON ZADORA-GERLOF The...ZADORA-GERLOF Including a mallard duck carved of indicolite tourmaline with diamondset collar and eye, signed...Born in 1944, Manfred Wild, an eighthgeneration gem cutter, is one of the most renowned lapidary artists...ART, GEMSTONES AND MINERALS | 17 2025 ENAMEL AND GEM-SET EGGCREATION--“GOLDFISH” BY MANFRED WILD Idar-Oberstein...AND MINERALS | 19 (details) 2026 W MAGNIFICENT GEM-SET OBELISK JEWELRY BOX BY MANFRED WILD Idar-Oberstein |
Gem gravels, Ratnapura, Ratnapura District, Sabaragamuwa Province, Sri Lanka