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| are the possiblesourcerock for many of the Ratnapura-type gem depositsin this area. The cordierite gneissesand...termed by Cooray (1962, p. 257) the "Southwest GEM CEYLON rocksalso belongto this paragenesis, but...sillimanite+ corundum q- sapphirine Fro. 1. The Ratnapura gem area (outlined) in relation to the occurrences...comparablerocksof Ceylon,althoughit is foundin the gem gravels. Most of the mineralassemblages listedabovewere...SiO2-A12Oa-MgOtriangle (Fig. 2). Ratnapura-type Gem Deposits Most of the gem fields are situatedin the southwest |
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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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| THE ORIGIN OF GEMSTONES TISSA MUNASINGHE OF SRI LANKA AND C. B. DISSANAYAKE Department of Geology...Geology, University of Peradeniya,Peradeniya,Sri Lanka Sri Lanka is well known throughout the world for its...topaz, and zircon. Largescale gem mining is confined mainly to the Ratnapura and Elahera areas (Fig. 1)...1). In most local- ities gem minerals are recovered from residual, alluvial, and eluvial depositsthough...common (Dahanayake et al., 1980). The gem-bearing beds in the Ratnapura area are mostly alluvial in origin |
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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' |
 | Giuliani, Gaston, Fallick, Anthony E., Boyce, Adrian J., Pardieu, Vincent, Pham, Van Long (2017) Pink and Red Spinels In Marble: Trace Elements, Oxygen Isotopes, and Sources. The Canadian Mineralogist, 55 (4) 743-761 doi:10.3749/canmin.1700009 | Journal (article/letter/editorial) |
| of the main productive and historical sources of gem spinel. Three consistent sets of d18O values were...study shows that it is possible to discriminate gem spinels hosted by marbles from different geographic...oxygen isotopes, geographic origin. INTRODUCTION Gem spinel belongs to the aluminous spinel subgroup A2ĂžB3Ăž2O4...Pardieu/GIA; (E) E. Gaillou/ENSMP. Badakshan Province in Afghanistan (Spencer 1937). In Roman times...SPINELS IN MARBLE FIG. 2. Location of pink and red gem spinel deposits (large star) and occurrences (small |
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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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| 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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| A DAY IN A CEYLON GEM FIELD Delaware' Josoru L. GrlrsoN, Wilmi'ngton, In March, 1932, having two free...arrangementsto quickly visit Ratnapura, 55 miles southeast of Colombo, the center of the gem-washing injourney in...to show me the promised who found was guide a Ratnapura, and in operation durstill were that places) (washing...idamas daYs. these depression ing-ttrat the -eylo.t gem fields have been known for a very long time is indicated...plagiarizes the tale in a more interesting manner'"1 Ratnapura (a Singhalese word meaning "City of Gems") is |
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| 5 JANUARY 1977 KORNERUPINE CAT'S-EYES FROM SRI LANKA (CEYLON) By H. J. KOREVAAR, F.G.A., Ter Aar, Netherlands...authors (Korevaar), visiting Sri Lanka, bought a parcel of 125 cat's-eyes from a gem dealer in Galle. Although...Weligama gem gravels in the Matara district. Back in Holland, Korevaar contacted the Dutch Gem Laboratory...trip to Sri Lanka in February 1976, the authors noticed a lot of these stones in the Ratnapura Gem Museum...stones offered for sale by people in the street in Ratnapura. It is very likely, therefore, that in the near |
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| extensive native plantations in the Northern Province, especially in the Jaffna Peninsula and the outlying...and December, the rainy season of the Northern Province. Sugar or âjaggery â is prepared from sweet toddy...stone inthe Western Province, or of tamarind wood in the North-Central Province; in this a heavy pesile...to one family of ivory workers in the Kegalla District. The little figures of the last King of Kandy...Chief Priest are said to be contemporary portraits. Sri Wikrama Raja Sinha was the last king of the Suluwansa |
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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 possessâapart, 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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| Edelseifen um Ratnapura . . . . . . . . . . 22 Lageskizze der Edelsteinfelder in der Provinz Sabaragamuwa Ceylons.... . . . .. .. .. . . . .. . . . . . . . . . . Amethyst (81) - Bergkristall (81) - Rauchquarz (8 2) -...Polonnaruwa ⢠Kandy Nuwara Eliya Adam's Peak Ratnapura ⢠.Pelmadulla ⢠Rakwana Malara Karte von Ceylon...altorientalisches Dichterwort die paradiesische Insel Lanka an der Siidspitze Indiens. Es hat bis heute seine...von Edelsteinen wie gerade Ceylon.Bereits in den Lanka-Sagen finden sich manche Hinweise auf Ceylons Edelsteinreichtum |
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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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| 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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| 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 Lankaâs 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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| 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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| and Sapphire CVD Synthetic Diamond and Synthetic Amethyst IdentiďŹcation VOLUME 47 Diamond Stamp Collection...reputation? Itâs the most reliable, authentic, dependable gem institute in the world. People know that, especially...Sapphire from the Tan HuongâTruc 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...Infrared Spectroscopy of Natural vs. Synthetic Amethyst: An Update Stefanos Karampelas, Emmanuel Fritsch |
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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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| 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-+ |
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| Dimensions in the captions refer to the entire gem or mineral; however, in some cases only a portion...Page 6: Mimetite (see page 139) Page 248: Quartz (amethyst variety), Erongo Mountains, Namibia * 5 x 6 x...A CHANGING PLANET 11 Vanadinite, San Carlos district, Chihuahua, Mexico * 8 x 4 x 2 cm Mineral Species...cavities are some of the worldâs finest crystals of amethyst, agate and a large family of silicate minerals...can be as valuable as the richly colored stones. Gem cutters bring out the inner beauty of gems by creating |
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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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| Gemesis CVD synthetic diamond New sapphires from Sri Lanka Cultured pearls from Micronesia VOLUME 48 NO...reputation? Itâs the most reliable, authentic, dependable gem institute in the world. People know that, especially...Sapphires from Thammannawa, Kataragama Area, Sri Lanka Pannipitiye G. R. Dharmaratne, H. M. Ranjith Premasiri...sapphires, the object of a recent gem rush in southeastern Sri Lanka, possess good transparency and a...research efforts have led to dramatic progress in gem-quality CVD synthesis and post-growth treatment. |
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| the authors 4 Iolite (cordierite) 55 Is it a gem? 5 Andalusite, Fibrolite (sillimanite) Finding...Malachite and Azurite 65 Opal 42 Lapis lazuli 66 Amethyst and Citrine 44 Moonstone and Labradorite 68...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 |
Gem gravels, Ratnapura, Ratnapura District, Sabaragamuwa Province, Sri Lanka