 | | Book | | " PP ^ |5& V:.^ jV-. ^: V-. ■• 4* ' N^Sri dr., > A i'-.v ' .1 • , ...,, i ■'>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 gem¬ The word diamond’ comes from the Greek 'Adamas' |  | | 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 ‘turbulent’, gem crystals will grow ceaaeos SI out of the solution |  | | Journal (issue) | | 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 |  | | Book | | 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 |  | | 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 ‘ag yet Gay x 2 WHAT IS A GEM? Gems are generally defined as precious or semiprecious |  | | Report (issue) | | 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 mar 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 |  | | 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 |  | | 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 |  | | Journal (issue) | | 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 |  | | 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 | | 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 |  | | Book | | gemstones and people who have a passion for stones and gem-set jewelry. It answers many of the questions | regularly...students and jewelry makers and designers about gem usage and features a broad range of gemstone materials...and how it handles. é Further sections cover gem-related topics such as the mining, selection and...continuing the cycle. Q eposits, such as river gravels, created by weathering and IGNEOUS ROCKS erosion...alluvial sedimentary deposits in the river gravels of Sri Lanka. GEMSTONE FORMATION Igneous PEGMATITE |  | | Journal (volume) | | necklaces and other ornaments. It occurs as rare gem-quality crystals and as shapeless specimens. D ...quartz was imported to Rome from mines in India, Sri Lanka and the Ural Mountains of Russia. Nowadays, the...comes from the metal chromium, which occurs in the gem crystal. The shade may vary according to the angle...Rangoon . Sri Lanka is another leading producer of rubies. The main centre there is Ratnapura, which means...form strange shapes. ► A beautifully cut artificial gem. Natural, artificial and inorganic Rocks are made |  | | Book | | Featuring an easy;to;use color key, information on gem lo re, gem care, and h ow to make your own jcwelry, DK...106 R EFERENCE SECTION 108 Legen dary gems 110 Gem care 117 Making j e\\7elr>~ 114 Table of properties...information about the myths and legends surrounding each gem. Label • J l I' AKIN G JEWELR Y Running U...These illustrate the most popular cuts for each gem (see page 29). GLOSSARY AND IN DEX At the back...of gemston es extended beyoRd the supen-iatural gem \Vere thought to have medicinal propertie . Chine |  | | Book (edition) | | Index 97 Lesson 8 Polarized Light and Colour in Gem Distinction Lesson 9 Luminescence, Electrical and...10 Loupe and Microscope 152 Lesson 11 Primary Gem Species 170 Lesson 12 Synthetic Gemstones 205...Lesson 18 Organic Gems 302 Lesson 19 Secondary Gem Species Bil Index O25 Digitized by the Internet...species. Webster originally wrote very little on the gem species, as he intended the book to be complemented...Primary Gem Species, the principal stones of the professional curriculum, and Secondary Gem Species |  | | Journal (issue) | | of western U.S. locations, including the Little Gem amethyst scepter mine in Montana, the Fluorita Dulcita...Rhodochrosite on Manganite N'Chwaning Mine, Northern Cape Province, South Africa. 8.7 cm In 1978 a historic discovery...emeralds. It has long been a commonplace in the gem trade that the world’s 2709 E. Exeter Street,Tucson...2022 finest gem-grade rubies are those from the Mogok Stone Tract, and that Mogok’s gem-grade sapphires...the gemology, treatment, cutting and marketing of gem corundum from Mogok, and—as a kind of resonance of |  | | Book (edition) | | expressed in abbreviations: Rep. (republic), prov. (province), co. (county), munic. (municipio), pref. (prefecture)...dept. (departement), dept. (departamento), dist. (district). Less common terms are not abbreviated, e.g....the revolution in 1997. Its mineral rich Katanga province was renamed Shaba by Mobutu, and is now the Katanga...Katanga administrative region again. The former Kivu province is now divided to three regions: INTRODUCTION...conditions in the gold-bearing "greenstone" in Abitibi province in northern Ontario and Quebec. Some genetic problems |  | | Report (edition) | | dmp.wa.gov.au/GSWApublications Cover photograph: Gem-quality, fancy yellow, rough, sawable diamonds (average...................... 21 East Kimberley Diamond Province.................................................................... 24 East Kimberley Diamond Province................................................................... 24 North Kimberley Diamond Province ................................................................... 26 West Kimberley Diamond Province.............................................. |  | Gaines, Richard V., Skinner, H. Catherine W., Foord, Eugene E., Mason, Brian, Rosenzweig, Abraham, King, Vandall T. (1997) Dana's New Mineralogy (8th ed.) Wiley-Interscience. p.1872 | Book (edition) | | British Columbia NF Labrador (part of Newfoundland Province) MB Manitoba NB New Brunswick NF Newfoundland...Co., Bonanza mine, Trinity Co., Michigan Bluff district, Placer Co., in AK, placers at Fairbanks, Iditarod...and quartz veins at Juneau. In Canada, Noranda district, PQ; Porcupine, Kirkland Lake, and Larder Lake...deposits, ON; Atlin and Caribou, BC; and Klondike district, YT. In Mexico, Altar and Magdalena, SON; Parral...localities, AZ; Calico district, San Bernadino Co., Cerro Gordo(*), Inyo Co., Bodie district, Mono Co., and other |  | | Book (volume) | | His works are known to almost every collector, gem cutter, gemologist, and mineralogist. His writings...newer events to bring the history of North American gem 1nining up to date. Here, then, is the latest, most...Systematic large-scale mining of sapphire-bearing gravels in Montana is beginning and is expected to produce...of turquoise and peridot, although for the latter gem, much larger facetable rough crystals appear with...will make it easier for readers to investigate the gem literature further or to obtain those references |  | | Book (edition) | | portion of an ore that is not economically valuable. gem A mineral that possesses intrinsic value because...Colorado at the Pelican Dives m.ine, Silver Plume district, and at the Little Emma mine, Clear Creek County;...lode, Summit County, and in the Cripple Creek district. It is also found in Canada; Mexico; Bolivia;...Califo1nia; in sodalite-syenite in the Julianehaab district, Greenland; in the liparite lavas of the island...slate and metamorphosed dolomite in the Beiyun-Obo district, Inner Mongolia, China, associated with aegirine |  | | Book (edition) | | used in gemology. It contains four color plates of gem min- sional and gems cut therefrom. The reason...gems, let if any, alone have a laboratory on gem materials. However, the student can read this chapter...Reading 509 468 13. Minerals As Gem Gem Minerals The Gem 510 510 Qualifications Types of ...Olivine 518 Gem Properties and Instruments for Their 518 Determination 524 Synthesis of Gem Materials 525...Rutile 528 Spinel 528 Turquoise 529 Manufactured Gem Materials Without Natural Counterparts 529 Garnet | | | Book (volume) | | His works are known to almost every collector, gem cutter, gemologist, and mineralogist. His writings...newer events to bring the history of North American gem mining up to date. Here, then, is the latest, most...Systematic large-scale mining of sapphire-bearing gravels in Montana is beginning and is expected to produce...of turquoise and peridot, although for the latter gem, much larger facetable rough crystals appear with...will make it easier for readers to investigate the gem literature further or to obtain those references |  | | Book | | E. Post, Geologist, Curator-in-Charge, National Gem and Mineral Collection, National Museum of Natural...are also triclinic. 24 MINERALS | GEMS GEMS A gem is any mineral that is highly prized for its beauty...from the tomb of Tutankhamun (c.1361–1352 BCE). GEM MINING Gemstone deposits form in different geological...diamonds are being recovered from a diamond pipe. Gem panning Many gemstone minerals, such as sapphire...sapphire and ruby, are heavier than normal stream gravels. These can be recovered using the slow but thorough | | | Book | | E. Post, Geologist, Curator-in-Charge, National Gem and Mineral Collection, National Museum of Natural...albite and microcline, are also triclinic. GEMS A gem is any mineral that is highly prized for its beauty...from the tomb of Tutankhamun (c.1361-1352.ce). GEM MINING Gemstone deposits form in different etched...diamonds are ibeing recovered from a diamond pipe. Gem panning Many gemstone minerals, such as sapphire...sapphire and ruby, are heavier than normal stream gravels. These can be recovered using the slow but thorough |
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Gem gravels, Ratnapura, Ratnapura District, Sabaragamuwa Province, Sri Lanka