 | | Journal (issue) | | 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' |  | | Journal (issue) | | 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 |  | | Journal (issue) | | Franks, B.Sc., Ph.D., F.G.A. South Yorkshire & District Branch: J. I. Platts, F.G.A. Examiners: A. J....of natural Tadparadschah ' sapphire found in Sri Lanka. However, a vast production of synthetic flux...'Padparadschah' sapphire Orange sapphire from Sri Lanka from Tanzania COMPARISON OF PHYSICAL PROPERTIES...Tadparadschah ' sapphires and orange sapphires of Sri Lankan and East African origins respectively and...Absorption spectrum of 'Padparaschah ' sapphire from Sri Lanka. (After Schmetzer et al., 1982) 800 I Cr3-+ |  | | Journal (article/letter/editorial) | | 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 |  | | Book | | 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 Ā« 2.00 ct and 3.06 ct leaves the gem, similar to what happens when you pass light through |  | | Book | | 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, |  | | Book | | 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 āag yet Gay x 2 WHAT IS A GEM? Gems are generally defined as precious or semiprecious |  | Voudouris, Panagiotis, Mavrogonatos, Constantinos, Graham, Ian, Giuliani, Gaston, Melfos, Vasilios, Karampelas, Stefanos, Karantoni, Vilelmini, Wang, Kandy, Tarantola, Alexandre, Zaw, Khin, Meffre, Sebastien, Klemme, Stephan, Berndt, Jasper, Heidrich, Stefanie, Zaccarini, Federica, Fallick, Anthony, Tsortanidis, Maria, Lampridis, Andreas (2019) Gem Corundum Deposits of Greece: Geology, Mineralogy and Genesis. Minerals, 9 (1) 49 doi:10.3390/min9010049 | Journal (article/letter/editorial) | | minerals Article Gem Corundum Deposits of Greece: Geology, Mineralogy and Genesis Panagiotis Voudouris... Abstract: Greece contains several gem corundum deposits set within diverse geological settings...āTi4+ pairs produce blue. Distinction of primary gem quality-rubies and sapphires in magmatic and metamorphic...southern Madagascar, East Africa, South India and Sri Lanka; those related to the Himalayan orogeny mostly...southeast Asia. The use of trace element content of gem corundums, in association with their oxygen isotopic |  | | Book (edition) | | 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 |  | | Book | | 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 |  | | Journal (issue) | | 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 |  | | Book | | 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 |  | | Report (issue) | | āThe Mineral Resources of the North-West Frontier Province. By A. L. Coulson. (Prioe As. 14 or la. 3d.) No...paper, ā Notes on Indian Precious Stones ā. 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 |  | | Book (edition) | | 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 |  | | Book | | 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 |  | | Book | | 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 āturbulentā, gem crystals will grow ceaaeos SI out of the solution | | | Book | | 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 |  | | Journal (issue) | | 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 |  | | Book | | Marvel over India's maharajahs, the world's greatest gem collectors, for whom no price was too great. Explore...star ruby on public display. A product of Sri Lanka's gem gravels, today it resides at the Smithsonian in...301 has yet to be surpassed for ruby. Today the gem is said to be 1n the personal collection of one of...of pure celestial blue Set i11 a golden band; A gem that owes its beauty to No lapidary's art, But to...origin is uncertain, but probably emanates from Sri Lanka. Today it rests in New York's Amer1can Museum |  | | Book | | region encompasses Ā·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 |  | | Journal (issue) | | Manager Telephone: [800! 4 2 1-7250 x 2 0 1 Editor, Gem Trade Lab Notes C. W. Frver Editor, Gemological Abstracts...Misiorowslzi Contributing Editor, John I. Koivula Editors, Gem News John I. Koivula Robcrt C. Kammerling SUBSCRIPTIONS...Robert E. Kane 47 54 Gem Trade Lab Notes Gems & Gemology Challenge 60 Gem News Book Reviews 62 ...only did the first Sumitomo gem-quality synthetic diamonds appear on the gem marlzet, but De Beers released...information revealing just how far their experiments with gem-quality synthetic diamonds had progressed; one such |  | | Book | | " PP ^ |5& V:.^ jV-. ^: V-. ā ā¢ 4* ' N^Sri dr., > A i'-.v ' .1 ā¢ , ...,, i ā '>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 gemĀ¬ The word diamondā comes from the Greek 'Adamas' |  | | Journal (issue) | | 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 |  | | Book | | TREASURES The IN THE SMITHSONIAN Gem Collection Paul E. Desautels ;".'*" - ā¢ * Ā« . ^- - ...: Ā»ā¢ā¢ * . 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 |  | | Book | | kyewitness CRYSTAL & GEM Apatite Cut topazes Calcite kyewitness CRYSTAL & GEM In association with...of an Indian woman ābedecked with jewellery Le GEM OF A CRYSTAL Ā© Most gemstones are natural crystals...two shadow edges, depending on | = | whether the gem is singly or doubly = | refractive, form ona scale...containing fine gemquality crystals are known as gem pockets. This gem pocket CHANGED BY FORCE As a result of...Quartz metamorphism. The blue kyanite and brown staurolite crystals in this specimen have been formed in |
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