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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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| 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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| 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 |
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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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| 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 |
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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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| 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...until its early eighteenth century arrival on the gem marĀ kets of Amsterdam, that tourmaline gained notice...from the Cingalese turamali (a mixed collection of gem rough), was introduced in Holland in 1703. The name |
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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 gemĀ¬ but was in turn scratched by those beneath stones...be unĀ¬ (9) and talc (1). For use in jewellery, gemĀ¬ 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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| 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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| 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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| Gems: A Historical Perspective Fred L. G r a y 202 Gem Andradite Garnets M.Stoclzton a n d D. V i n c e...FEATURES 232 238 246 249 252 Gem Trade Lab Notes Gemological Abstracts Gem News Book Reviews Suggestions...system contributed t o the demise of the engraved gem seal. During the thousands of years that the seal...most important mark of identification, however, gem engravingreigned as one of his most significant art...engraving process itself, h o w to evaluate an engraved gem, and more recent developments i n the materials and |
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| 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 |
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| Diamond Industries: 143,145. Acknowledgments: A & S Gem & Mineral Co., Lazare Kaplan International, Goldberg-Weiss...20 21 23 23 24 25 26 Introduction Gem History What Are Gems? Gem Criteria Origin of Gems Marketing of...Brilliancy Specific Gravity Luster and Fluorescence Gem Cutting 31 Gems and Gemstones 32 Diamond 44 Beryl...Irradiation 150 152 153 154 155 156 Gems as Investments Gem Testing Lapidary Hobby Jewelry Metals Popular Styles...is due to their unique properties. The colors of gem materials are among the richest and purest in nature |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| North-West Branch: 1. Knight, F.G.A. South Yorkshire & District Branch: J. I. Platts, F.G.A. Examiners: B. W....is well known to all experts that the colour of a gem, whether natural or man-made, is the least dependable...(healed fractures) in natural rubies from Burma, Sri Lanka and Thailand. Far more difficult to determine...twin-lamellae can be followed deep into the interior of the gem, the synthetic growth-bands disappear when raising...ruby crystals cut, and thus introducing them on the gem market, and as this possibility must be taken into |
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| Corundums Sapphire: Lord Keeper of the Seals in the Gem Kingdom Beryl: Palette of Pastel Colors Emerald:...total beauty. The investigation and explanation of gem colors forms one of the most exciting chapters of...taken place, loose strata were formed, such as gravels, sands, and clays, deposited from water and air...often called placer deposits or alluvial gem gravels. Such gravels are found both in present-day stream beds...Obviously this can only signify that formations of the gem-rich phases of the sial cropped out particularly |
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| habits What is a gem? Visual properties Where do gems come from? Grading and evaluation Gem cuts The value...value of a gem What is a jewel? NATIVE ELEMENTS Gold Crown of Charlemagne Silver Platinum Marie Antoinetteās...Chrysocolla Petalite Prehnite Phosphophyllite The gem industry Enstatite Diopside Hypersthene Bronzite...burials and the Romans were also fond of using it. The gem went out fashion for a time, but enjoyed a resurgence...emerald, tourmaline, and aquamarine. Other types of gem, released from their original rock by weathering |
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| them. Until recently mineral-collecting was the province of the mineralogist, the miner or the wealthy...peninsula in Michigan, U.S.A.; the Lake Superior district, and Cobalt, Ontario. Small amounts have been...Queensland and New South Wales; the Mother Lode district of California and parts of Colorado, U.S.A.; Canada;...yellow, brown (dravite), etc., and colourless (achroite) - all transĀ¬ parent. Also opaque black {schorl)...Urals; the island of Elba; Burma; the Ceylon gem gravels; Alamos in Mexico ('watermelon' colour-zoned |
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| run verticall y or horizontally righ t across the gem surface. Onyx is very popu lar in pe n da n t s an...have been the name of a town in ancient Egypt. A GEM AND A ROCK I I Most alabaster is defined as the...be artificially ""tJ Right: Although the term 'gem' is most commonly associated with the precious mountings...alabaster from Volterra, near Pisa (Italy). This gem material is basically the mineral gypsum. Although...now exhausted, but the gem can still be found in small quantities in Sri Lanka, Burma and Brazil. Alexandrite's |
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| * * To my wife, who put up nobly with being a gem widow. A cknowledgements I am very grateful to the...Structure of Gemstones and their Imitations 35 The Gem Species 58 The Gemstone Industries 108 The Evolution...of these are capable of use as gems. While a few gem-forming minerals are relatively common, most are...annually. All this is, however, completely useless for gem purĀ¬ poses. The material is greyish and opaque; it...mined to win the gemstones. Even then most of the gem beryl will be wasted-either discarded as inferior |
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| Forn1ation of Gemstones 26 34 The Description of Gem..~tones contained in the Collection . .. ā¢ā¢ā¢ 76 Appendix...(The pearl, although probably the most valuable gem at the present time, is excluded, as it can hardly...topaz, 01"' zircon, which is in vogue ; the favoured gem consequently tlses in value 11nt,il some new whim...Craft,'' by Leopold Claremont. ā¢ 1906 . a ā¢ā¢ '' Gem-Stones,'' by G. F. H. Smith. 1912. '' Die Farben...polished plates of the minerals 6 to 9 and to rt1b the gem successively over them, beginning with number 6, |
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| Printed 1n Ch ina CONTENTS Foreword 4 INTRODUCTION Gem Formation 6 Minin g 10 Th e Diamond Industry 14 Diamond...Jewelry 68 Color Key 70 Class if ication 77 GEM S 78 Important Gem Locations of the World 243 G lossary 252...real genf' and "this book is a liule gem." In this context a gem b so1nelhing special, highl y \'alued...n1ay ~1dd to the rarity. desirabil ity. and value. GEM QUALITY Rocks are 1nade of minerals, but no t a ll...a re gene rally re ferred to as "cultable " o r "gem qua lity" crystals. I \ TRAN SPORT / METAMORPHISM |
