 | | Book | | 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; | | | Book | | 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; |  | | Journal (issue) | | 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 |  | | Journal (issue) | | invite you to be our guest at Hong Kong Jewellery & Gem Fair September 16th-20th 2019 AWE - Booth 8E03 German...Spinel Pink and Red Gem Spinels in Marble and Placers Spinel from Tajikistan – The Gem That Made Famous...Spinels of Mogok – A Brief Overview Spinels from Sri Lanka 54 The Spinels of Mahenge, Tanzania In Search...Responsibility 94 Book Review Discovering the Gems of Sri Lanka 98 100 108 113 Members 14 Saurabh Bansal Damien...Shirley Xue Li Zhang, Hong Kong E. Gamini Zoysa, Sri Lanka Advisors Jean Claude Michelou, Colombia Ruben |  | | Journal (article/letter/editorial) | | of gems found in alluvial deposits of the Ratnapura district now runs to several million pounds, it is...fortunate in discovering a new corundum locality where gem-quality sapphire has developed along the contact...addition of cordierite, almandine garnet, and pleonaste to the assemblage, the latter being so nearly...and the exit of cordierite, sillimanite, and pleonaste. There is thus a passage both along and across...detail of habit to the crystals recovered from gem gravels some 20 miles to the south-west. A high proportion |  | | 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 | | r· Butterworths Gem Books Edited by Peter G. Read Amber Helen Fraquet Beryl John Sinkankas and Peter... Huddlestone Topaz D. B. Hoover Butterworths Gem Books Corundum Richard W. Hughes Executive Vice...Corundum/Richard W. Hughes. p. cm.-{Butterworths gem books) Bibliography: p. Includes index ISB!'i 0-7506-1006-9:... Major sources: Burma, Thailand, Cambodia, Sri Lanka, India, Australia, Kenya, Tanzania, Montana and...we have books on gem deposits, the lapidary arts, carved gems, gem treatments, gem identification, history |  | | Journal (issue) | | 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 |  | | Journal (issue) | | Branch: M. P. Gayton, F.G.A. South Yorkshire & District Branch: M. W. Eldridge, M.B., Ch.B., F .G.A. Examiners:...NOTES FROM THE LABORATORY By A. E. FARN, F.G.A. The Gem Testing Laboratory, London Chamber of Commerce and...what great expenditure goes to produce 1 carat of gem diamond—probably paralleled only by the enormous...good lighting conditions of one only variety of gem, namely colourless diamond. There is no doubt at...is another oddly apt phrase when considering the gem world. Returning but briefly to pearls, the imitation |  | | 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 | | 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 | | 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 |  | | Book (edition) | | 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 |  | | Journal (issue) | | 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 |  | Giuliani, Gaston, Groat, Lee, Fallick, Anthony, Pignatelli, Isabella, Pardieu, Vincent (2020) Ruby Deposits: A Review and Geological Classification. Minerals, 10 (7) 597 doi:10.3390/min10070597 | Journal (article/letter/editorial) | | uncommon on Earth but the gem varieties of ruby and sapphire are relatively rare. Gem corundum deposits are...specifically Type IA where xenocrysts or xenoliths of gem ruby of metamorphic (sometimes magmatic) origin are...models; exploration 1. Introduction Ruby is the red gem variety of the mineral corundum. The name corundum...depending on which direction light travels inside the gem. In gemmology this is of critical importance because...depending on how they decide to orientate and cut the gem. The ruby industry is very lucrative [5] but it is |  | Wang, Kandy K., Graham, Ian T., Lay, Angela, Harris, Stephen J., Cohen, David Ronald, Voudouris, Panagiotis, Belousova, Elena, Giuliani, Gaston, Fallick, Anthony E., Greig, Alan (2017) The Origin of A New Pargasite-Schist Hosted Ruby Deposit From Paranesti, Northern Greece. The Canadian Mineralogist, 55 (4) 535-560 doi:10.3749/canmin.1700014 | Journal (article/letter/editorial) | | Melbourne, Melbourne, Victoria, Australia ABSTRACT Gem-quality (cabochon) ruby-bearing occurrences (here...Humanity has long had a fascination with the red gem variety of corundum – ruby. The rarity of the stone...continent of Greenland. Ruby and sapphire are both gem varieties of the mineral corundum. Pure corundum...et al. 2007). Based on trace element analysis of gem corundum grains, the FeO–Cr2O3– MgO–V2O3 versus FeOþTiO2þGa2O3...constrain the geological environment of formation of gem corundum (Giuliani et al. 2010, Giuliani et al. 2014b) |  | | 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 | | and Zirconolite Inclusions in Marble-Hosted Gem-Quality Ruby and SpinelfromMogok,Myanmar Reprinted...Secretary and Chairman for the IMA Commission on Gem Materials. In his research he has authored and co-authored...valuable gem minerals within the annals of natural gemstone studies, namely ruby, the red-colored gem variety...V.; Wang, K.; Tarantola, A.; Zaw, K.; Meffre, S. Gem corundum deposits of Greece: Geology, Mineralogy...into the more general populace. It is an important gem for scientific study [4] and for exploration quests |  | | Journal (issue) | | however, certainly significant for it is known that gem kornerupine is pseudo-uniaxial. 73 Everything then...stones known to have come from the Ceylon (Sri Lanka) gem gravels and neither showed any fluorescence. However...seen it, is said to have produced a beautiful green gem. Thanks are due to Messrs Wolff of Hatton Garden... X X I V (288), 129. Anderson (B. W . ) , 1971. Gem Testing. 8th edn, London (Butterworths), p . 361...are red and brilliant, a n d variations in this gem have given rise to several species." (His "spinellus" |  | | Journal (article/letter/editorial) | | J. A. (1905) The gem gravels of Kakanui, with remarks on the geology of the district. Trans. N. Z. Inst...oriented octahedra (up to 3 mm) of nearly opaque pleonaste. Augite resembles that of assemblage (6) but has... 7 9 0 + 0 . 0 0 5 o : 8 . 1 4 A 8. Augite (*pleonaste & olivine inclusions) : Large (100 cc) crystal...inclusions of a similar pyroxene and purple-gray pleonaste. Spinel concentrated in linear zones, possibly...replaced by iddingsite and carbonate; olive-green pleonaste grains equant, up to 5 mm, or vermiform and moulded |  | | Journal (article/letter/editorial) | | have recently examined a large quantity of coarse gem-gravel refuse obtained from the Balangeda and l~akwana...predominates, while tourmaline, corundum, and pleonaste are fairly abundant. Among other minerals present... of iron oxide is comparatively rare in the gem-gravels. More commonly, varieties occur which are somewhat...occur in considerable quautities in the Balangoda district. It has a specific gravity of 4.25, when fresh |  | | Book | | culture, derives its name from the saltmining district of Hallstatt in Upper Austria, where many prehistoric...The sedimentary rocks 1 RESIDUAL ROCKS grit, gravels (in part), weathered clay, laterite, bauxite 2...than 2 mm.): grits and breccias (angular grains), gravels, conglomerates (rounded grains), moraines and tillites...have been concentrated by secondary enrichment. Gravels are partly residual formations and partly elastic...by rivers; tidal action forms gravel beaches. Gravels may be loose or recemenced, and they are formed |  | | Book | | State. This must give opal the rank of our premier gem. The mining for gemstones has been carried out by...materials. Opal when too poor in quality for use as a gem may be used for inlay work or as backing to the precious...publications:Baxter, T. C. and Dake, H. C., 1938. Jewellery, Gem Cutting and Metalcraft. McGraw Hill, New York. Pearl...Sinkankas, J. 1955. Gem Cutting. Van Nostrand, New York. Williams. J. D. 1948. Gem Cutting (revised 1952)...hyalite from north of Cookabiandi in the Namoi River District. W. H.J. Slee (1895) states: "Fourteen (14) years |  | | Report (issue) | | determine the suitability of a stone for use as a gem are beauty or decorative value, rarity and durability...number of these so as to bring the terminology of the gem tr.a;der into line with that of the mine1~a1ogist...elaborate scientific instr11ments are often of use in gem determination. A small pocket refractometer with...X-rays and cathode rays in the determination of gem minerals, · especially for detecting doublets and...great variation in the weights used by different gem dealers.* Practically all countries have now agreed |  | | Book | | GEMSTONES FOR EVERYMAN by the same author GEM TESTING {8th revised edition published in 19JI by...12^) A. Granite with topaz crystal B. Ceylon gem gravel C. Corundum group D. Chrysoberyl and spinel...Removing the overburden covering diamondiferous gravels on coast of South West Africa II ILLUSTRATIONS...copyright facilities. For the picture of Ceylon gem gravel I have to thank my old friend Mr. R. K. Mitchell...in certain of their varieties, quite important as gem materials. This may well astonish an innocent reader |
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