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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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| Tribute to Robert M. Shipley, Jr. The Chanthaburi-Trat Gem Field, Thailand Peter C. Keller 197 Gemstones with...Effect E. Giibelin and K. Schmetzer 204 Gem-Quality Grossular Garnets D. Vincent Manson and Carol M. Stockton...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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| 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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| 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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| Sediment Geochemistry of the Walawe Ganga Basin of Sri Lanka - Implications for Gondwana Mineralization Rohana...Geology, University of Peradeniya, Peradeniya, Sri Lanka * Corresponding Author (Manuscript received September...western-part of the Walawe Ganga (river) Basin in Sri Lanka is represented in this paper. The river basin...Walawe Ganga Basin, Sri Lanka. Introduction More than 90% of the island of Sri Lanka is made up of amphibolite...(1994) revised the subdivisions of Precambrian Sri Lanka based on the geochronological, petrological and |
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| NOTES FROM THE LABORATORY By A. E. FARN, F.G.A. The Gem Testing Laboratory, London Chamber of Commerce and...n d doubled our charges. * * * A parcel of 25 grossular garnets recently submitted for our interest varied...pleasure) was a beautiful oval faceted deep yellow grossular garnet weighing 13*89 ct. T h e stone h a d a...Apricot Province ___________ Teita Province Morgans Mine Mine Kenya Kenya Teita Province Bridges Mine...Emerald Green 1·741 19. Gros~~.dar Gr~en 1·741 20. Grossular Green 1·740 21. Deep Gross. Green Light Tou~~ |
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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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| 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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| 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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| 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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| 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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| 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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| 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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| 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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| 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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| 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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| 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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| 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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| 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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| 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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| 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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| 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 |
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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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| 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 |
Gem gravels, Ratnapura, Ratnapura District, Sabaragamuwa Province, Sri Lanka