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| and Liddicoatitic Tourmalines ANJANABONOINA DISTRICT, MADAGASCAR T he tourmaline database, like that...calcium analogue of the well-known gem and specimen species elbaite (Dunn, Appleman, and Nelen 1977).... The relationship between liddicoatite and elbaite seemed clear, and liddicoatite’s fundamental place...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 |
 | Bosi, Ferdinando, Skogby, Henrik, Ciriotti, Marco E., Gadas, Petr, Novák, Milan, Cempírek, Jan, Všianský, Dalibor, Filip, Jan (2017) Lucchesiite, CaFe2+3Al6(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup. Mineralogical Magazine, 81 (1) 1-14 doi:10.1180/minmag.2016.080.067 | Journal (article/letter/editorial) |
| tourmaline supergroup. It occurs in the Ratnapura District, Sri Lanka (6°35′N, 80°35′E), most probably from...of ∼7 and a calculated density of 3.209 g/cm3 (Sri Lanka) to 3.243 g/cm3 (Czech Republic). In plane-polarized...intensity data. Crystal-chemical analysis for the Sri Lanka (holotype) and Czech Republic (cotype) samples...deposited: (1) the holotype specimen from Ratnapura, Sri Lanka, in the collections of the Museum of Mineralogy...Fluor-species Fluor-dravite Fluor-schorl Fluor-elbaite Fluor-tsilaisite a Formula Reference NaCr3( |
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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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| 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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| 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, M...significant find of gem quality elbaite (lithium tourmaline) was made at the Dunton gem mine, Newry, Maine...and the description of the elbaite was given by Dunn (1975). The elbaite occurs in a lenticular pegmatite...Newry Hill. The pegmatite had long been noted for elbaite and many of the finest examples of New England |
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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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| 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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| 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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| 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...northern Kenya • Black spinel from Mexico • Nigerian elbaite with Cu • Vesuvianite from Kenya and Madagascar...CA 92008 (760) 603-4504 akeller@gia.edu Editors, Gem Trade Lab Notes Thomas M. Moses, Ilene Reinitz, Shane |
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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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| 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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| 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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| 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...proved to be members of the solid solution series elbaite-tsilaisite (manganese tourmaline). The mechanism...tourmalines and the formula of the end members in the elbaite-tsilaisite solid solution series are discussed |
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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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| 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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| 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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| No. 8 / 2019 COLUMNS What’s New 679 ABCD Pro-1 Gem Testing Set | D-Imaging Device | Raman Spectroscopy...| Jewelry Journey Podcasts | Gemewizard Gem Color Academy Gem Notes Amethyst from Zimbabwe | Apatite...Fuchsite Phantom Inclusions | Tourmaline from Sri Lanka with Transient Tenebrescence? | Diving for Natural...710–725 of this issue) and therefore does not have a Sri Lankan origin as commonly described for Roman sapphires...Trapiche Ruby from Khoan Thong, Luc Yen Mining District, Northern Vietnam 726 By Isabella Pignatelli |
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| GS/GN A lifesize pen and ink render ing of elbaite crystals with lepidolite from the Golconda Mine...Maximilian Glas ............ 62 • Inclusions in Elbaite Crystals .......... 64 John I. Koivula • If Icarus...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 |
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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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| 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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| 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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| weighing tens of kilograms have been seen at major gem and mineral shows. Downloaded by [University of...to 11 cm long and 9 cm across associated with elbaite, microcline, and stilbite) and the Chuqui mine...during 2003 are the Mineral Section of the Houston Gem and Mineral Society and the Cincinnati Mineral Society...length have been available from the Alto Chapare district, Cochabamba, Bolivia (Petrov 2003). Here it is...length have been found in the Bor open pit of this district (Grant and Wilson 2001). Other Russian localities |
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| gemstones survive it all. On the other way round, gem minerals can also be used as pathfinder minerals...linked to these gemstones in magmatic and metamorphic gem deposits. All placer types known to be relevant for...corundum. Minerals 2018, 8, 470 3 of 43 Table 1. Gem minerals found in placer deposits, their physical...their source rocks and the sedimentary traps. The gem placer deposits are subdivided according to the “Chessboard...Brazil, Tarkwa, Ghana, and the Guyana area histories gem deposits discussed later in the study. Besides gold |
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| Journal of Gemmology THE GEMMOLOGICAL ASSOCIATION AND GEM TESTING LABORATORY OF GREAT BRITAIN OFFICERS AND... R. Cavey, FGA The Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street...ISSN: 0022-1252 J. Gemm., 1991,22,8 458 THE GEM DIAMOND DIPLOMA GAGTL have brought together the finest...world of diamonds to produce the most comprehensive Gem Diamond home study course available. The course acknowledges...international diamond market and includes every aspect of gem diamond you will ever need to know. Following an |
Gem gravels, Ratnapura, Ratnapura District, Sabaragamuwa Province, Sri Lanka