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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. 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 |
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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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| 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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| 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...and zircon from Ethiopia • Sapphire mining in Sri Lanka • Green cat’s-eye spodumene from Brazil • Color-zoned |
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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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| Hays A Prospectors' Guide Map to the Gem Deposits of Sri Lanka C. B. Dissanayuke and M.S . Rupasinghe...Fritsch, and llene Reinitz REGULAR FEATURES Gem Trade Lab Notes Gem News Book Reviews Gemological Abstracts...Hey1 Contributing Editor John I. Koivula Editor, Gem Trade Lab Notes Editor, Gemological Abstracts C....Gems & Gcmology, contact the Association of Japan Gem Trust, Okactumachi Cy Bldg., 5-15-14 Ucno, Taito-ku... Technical Editor Carol M. Stoclcton Editors, Gem News John 1. Koivula Robert C. Kammerling Emmanucl |
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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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| 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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| 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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| 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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| 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 |
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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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| 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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| Association and Gem Testing Laboratory of Great Britain Gemmological Association and Gem Testing Laboratory...No.2, April 1998 ISSN: 1355-4565 Distinctive gem corundum suites from discrete basalt fields: a comparative...suites of remarkable similarity. Two distinctive gem corundum suites appear in eluvial and alluvial deposits...deposits from the Barrington basalt province in New South Wales, one typical of East Australian sapphire...typical Australian © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355-4565 |
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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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| desert seem unlikely surroundings for a thriving gem min ing industry that was carried on- before the...shores of the Red Sea for further transport to the gem-cutting and goldsmithing workshops of Egyptian, Mediterranean...known as Sri Lanka) where waterworn pebbles of aquamarine were found in the gembearing gravels and, similarly...similarly, in the gem gravels of the Mogok district of Burma. Emeralds, especially, were known to native...century. In 1912, A . Eppler, the famous German gem expert, proposed the name bixbyite for this variety |
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| North-West Branch: R. Perrett, FGA South Yorkshire & District Branch: G. A. Massie, FGA Examiners: A. J. Allnutt...revealed the stone to be a very unusual assembled gem in which a small chunk of natural Burmese ruby was...Richard W., 1984. Surface repaired rubies a new gem treatment. Journal of Gemmology, 19, 4, 384-6. Scarratt...Gemmological Association has collaborated with the Gem Testing Laboratory of Great Britain to arrange a...Association by Ken Scarratt and will be held at the Gem Testing Laboratory in London.The aim is to give practical |
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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 |
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| Journal of Gemmology The Gemmological Association and Gem Testing Laboratory of Great Britain OFFICERS AND...Mary A. Burland The Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street...Edward J. Gübelin6 and Alfred A. Levinson7 1. GIA Gem Trade Laboratory, Santa Monica, USA 2. AIGS, Bangkok...he was asked to survey and report on the mining district by the concessionaires. The map he produced at...24, 1 6 Table 1: Gem minerals reported from Myanmar (Burma), including organic gem materials (compare |
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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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| 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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| January 1996 The Gemmological Association and Gem Testing Laboratory of Great Britain President E...B.5c., FGA DGA The Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street...of minerals associated with the rubies in the gem gravels, are considered in modelling how the particular...Journal of the great potential of Russia for supply of gem materials, and amber possibly having come from this...this source is described in Notes from the Gem and Pearl Testing Laboratory, Bahrain. The composition |
