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| Introduction Petrographicand field studies of the cordierite gneissesfrom southwestCeylon (Fig. 1), have outlined...possiblesourcerock for many of the Ratnapura-type gem depositsin this area. The cordierite gneissesand related si...hasbroughtout the regional importanceand setting of the cordierite gneisses which now make up a low-pressurefacies...termed by Cooray (1962, p. 257) the "Southwest GEM CEYLON rocksalso belongto this paragenesis, but...the cordierite gneisses(e.g. (6)) implies local Group." COLOMBO Petrography of the Cordierite Gneisses |
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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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| Geochemistry of Beryllium and Fluorine in the Gem Fields of Sri Lanka M. S. Rupasinghe 1, A. Banerjee 1, j. Pense...Peradeniya, Sri Lanka Abstract. A study of the abundance of Be in the gem sediments of Sri Lanka shows that...pegmatites of the Highland and Southwest Groups of Sri Lanka, very little decomposition of the Be-bearing minerals...granites and pegmatites of the Precambrian of Sri Lanka are presumed to have been formed due to the magmatic...charnockitic rocks abundant in the main gem bearing areas of Sri Lanka. Fluorine is found in the range of |
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| element abundance in the sedimentary gem deposits of Sri Lanka M.S. RUPASINGHE and C.B. DISSANAYAKE*...element abundance in the sedimentary gem deposits of Sri Lanka. Lithos, 17: 329-342. This study reports...(rare-earth elements) data from the gem-bearing sediments in Sri Lanka. The REE in these placer deposits...marked similarity with those for charnockites in Sri Lanka as well as for charnockite-granite rocks in other...negative Eu-anomaly. From the general geology of the gem fields and from the REE data it appears that the |
 | 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 A2ĂľB3Ăľ2O4...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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| 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' |
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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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| in stream sediments of a granulite terrain in Sri Lanka — evidence for a mineralized belt Rohana Chandrajith...Geology, UniÕersity of Peradeniya, Peradeniya, Sri Lanka Received 17 March 1999; accepted 11 May 2000 ...located in a high-grade metamorphic terrain of Sri Lanka have been analysed for their major and trace element...Stream sediment; Geochemistry; Walawe Ganga Basin; Sri Lanka 1. Introduction ) Corresponding author. Fax:...Faculty of Applied Sciences, Sabaragamuwa University of Sri Lanka, Buttala, Sri Lanka. The Walawe Ganga ŽGanga |
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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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| anorthosite complexes. Association: Sapphirine, cordierite, spinel, corundum, tourmaline, grandidierite...Bok se Puts Farm, Namaqualand, Cape Province, South Africa. Gem crystals from Itrongahy, near Betroka...Madagascar. From gem gravels of the Matale, Ratnapura, and Embilipitiya districts, Sri Lanka. In the Harts |
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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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| 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 |
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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 “jaggery ” 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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| 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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| 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 |
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| leucogranites in Africa. This Mesoproterozoic tin province will be compared to the tin belt in SE Asia as...031, India Peradeniya University, Peradeniya, Sri Lanka Supercontinent Assembly, Dispersion and Reassembly...al., 1997 in MDG; Windley eta]., 1997, ibid), Sri Lanka (Yoshida et al., 1996 in NIPR-AB), India (Harris...the Gem Gravels of Sri Lanka D .J.A.C. Hapuarachchi 48/14. Old Kesbewa Road, Nugegoda, Sri Lanka Gem...Gem quality corundum is found in the gravels of Sri Lanka, and its origin has been dealt in Hapuarachchi |
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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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| 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 « 2.00 ct and 3.06 ct leaves the gem, similar to what happens when you pass light through |
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| the Gem Gravels of Sri Lanka D .J.A.C. Hapuarachchi 48/14. Old Kesbewa Road, Nugegoda, Sri Lanka Gem...Gem quality corundum is found in the gravels of Sri Lanka, and its origin has been dealt in Hapuarachchi...Hapuarachchi (1989). The ultimate origin of gem corundum has been a long standing question. It is generally believed...pegmatites. But the abundance of corundum in the gem gravels would certainly require a very productive source...that the source rocks of the corundum in the gem gravels are the corundum-bearing gneisses which form |
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| 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...magnesia and iron. This leads to the addition of cordierite, almandine garnet, and pleonaste to the assemblage...quartz, plagioclase, and pyroxene, and the exit of cordierite, sillimanite, and pleonaste. There is thus a...detail of habit to the crystals recovered from gem gravels some 20 miles to the south-west. A high proportion |
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| Edelseifen um Ratnapura . . . . . . . . . . 22 Lageskizze der Edelsteinfelder in der Provinz Sabaragamuwa Ceylons...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...ausser Gewiirzen auch Perlen und edle Steine aus Lanka, wie Ceylon im Altertum hiess, exportiert wiirden |
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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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| 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 |
