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| D) World Production E) South African Diamond Occurrences 1. Large Kimberlite Mines 1.1 Venetia 1.2 Premier...Koffiefontein 2. Smaller mineralised kimberlites in South Africa 2.1 The Oaks 2.2 The Zebediela Kimberlites 2...relative production contributions in South Africa were, primary (kimberlite) 8.63 million carats (89% of total)...Premier mine. The proportion of gems in the West Coast marine deposits is over 98%. The MIBA mine in the...the Congo and the Argyle mine in Australia have an average gem content of only 5%. The dispersal of diamonds |
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| g e o r ev Kimberlite-hosted diamond deposits of southern Africa: A review Matthew Field a,â, Johann...Southdale, 2135, South Africa c De Beers Group Services, PO Box 47, Kimberley, South Africa d De Beers Canada...Available online 22 April 2008 Keywords: Diamond Kimberlite Diatreme Pipe Dyke Mantle-xenolith Diamond-inclusion...discovery of diamonds in river deposits in central South Africa in the mid nineteenth century, it was at Kimberley...recognized. These volcanic rocks, that were named âkimberliteâ, were to become the corner stone of the economic |
 | Perritt, S., Preston, R., Viljoen, F., Van Der Linde, G. (2015) Morphology, Micro-Structure and Chemistry of A Deformed Garnet Megacryst Suite From Monteleo Kimberlite, Free State Province, South Africa. South African Journal of Geology, 118 (4) 439-454 doi:10.2113/gssajg.118.4.439 | Journal (article/letter/editorial) |
| MEGACRYST SUITE FROM MONTELEO KIMBERLITE, FREE STATE PROVINCE, SOUTH AFRICA. S. PERRITT Previous address:...2006, South Africa Current address: De Beers Group Services, Private Bag X01, Southdale, 2135, South Africa...Services, Private Bag X01, Southdale, 2135, South Africa e-mail: robin.preston@debeersgroup.com F. VILJOEN...Johannesburg, PO Box 524, Auckland Park 2006, South Africa e-mail: fanusv@uj.ac.za G. VAN DER LINDE De...Services, Private Bag X01, Southdale, 2135, South Africa e-mail: gert.vanderlinde@debeersgroup.com Š |
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| Extraterrestrial inclusion in ruby ⢠Fingerprint in spinel ⢠Complex fluid inclusion in topaz ⢠Vietnamese...success ⢠Yellow Sri Lankan sapphire jewelry ⢠Gray âspinel sistersâ ⢠An opal dealerâs battle with COVID-19...message ⢠Market reaction to the pandemic ⢠Mercury Free Mining ⢠Opal treated with sugar/heat ⢠Gianmaria...repair of an emerald ⢠Yellowish green enstatite ⢠Star topaz from Vietnam ⢠Davemaoite inclusion in diamond...Paris, France New York, New York Johannesburg, South Africa Al Gilbertson Laura Otter Wuyi Wang Carlsbad |
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| SURVEY OF SOUTH AFRICA COUNCIL FOR GEOSCIENCE GEOLOGICAL SURVEY OF SOUTH AFRICA MINERALOGY OF SOUTH AFRICA:... COUNCIL FOR GEOSCIENCE GEOLOGICAL SURVEY OF SOUTH AFRICA Scientific Editor R.D. Dixon Linguistic and...Council for Geoscience (Geological Survey of South Africa), 280 Pretoria Street, Silverton, Pretoria or........................... 69 5.1 Overview of South African Occurrences ..............................LAYEREDSUITE,BUSHVELDCOMPLEX.... 111 MINERALOGY OF SOUTH AFRICA: TYPE-MINERAL SPECIES AND TYPE-MINERAL NAMES |
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| the Cruzeiro tourmaline and mica mine and the Jacobina amethyst mine. He owns several other mines as well...the history of mankind. To the impecunious and the free spirit it meant sudden wealth; to the more worldly-wise...who is to gainsay the latter? In this treacherous field, where natural wonders can be duplicated with synthetic...of transience precious stones in their natural state or else transformed into works ofart thus assume...traditionally more desired stones. Diamond mining in the state ofBahia, during the Empire. Freed from traditional |
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| Burmese sapphires from Mogok, based on a series of field expeditions over the last decade. 318 Gemological...Vaterite on strand of freshwater cultured pearls ⢠Star rhodochrosite ⢠31 ct orange sapphire ⢠Flux-induced...in Burmese sapphire ⢠Chondrodite in Burmese red spinel ⢠Black coral with polyp structure ⢠Demantoid...sales of pink and blue diamonds from the Argyle mine ⢠Chalcedony-epoxy composite imitation of âcandy...Paris, France New York, New York Johannesburg, South Africa Al Gilbertson Laura Otter Wuyi Wang Carlsbad |
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| CHROMIAN AND ALUMINOUS SPINEL MACROCRYSTS FROM KIMBERLITES IN SOUTHERN AFRICA DANIEL J. SCHULZE§ Department...of the major- and minor-element compositions of spinel-group minerals that occur as single-crystal macrocrysts...macrocrysts in kimberlites from southern Africa (approximately 1500 grains from 20 kimberlites on the Kaapvaal...from a variety of mantle xenoliths from southern Africa and North America (approximately 150 xenoliths)...leads to the conclusion that most macrocrysts of spinel-group minerals are likely to be xenocrysts from |
 | Coe, Nancy, le Roex, Anton, Gurney, John, Pearson, D. Graham, Nowell, Geoff (2008) Petrogenesis of the Swartruggens and Star Group II kimberlite dyke swarms, South Africa: constraints from whole rock geochemistry. Contributions to Mineralogy and Petrology, 156 (5) 627-652 doi:10.1007/s00410-008-0305-1 | Journal (article/letter/editorial) |
| Petrogenesis of the Swartruggens and Star Group II kimberlite dyke swarms, South Africa: constraints from whole rock...Thirty-seven samples from the Swartruggens and Star Group II kimberlite dyke swarms, emplaced through the Kaapvaal...normalised La/Yb ratios (Swartruggens = 94 Âą 21; Star = 202 Âą 36). 87Sr/86Sr (0.70718â 0.71050) ratios...illustrated by crossing rare earth element patterns. The Star kimberlites have derived from a less radiogenic...Sciences, University of Cape Town, Rondebosch 7701, South Africa e-mail: anton.leroex@uct.ac.za D. G. Pearson |
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| testing in Hong Kong 691 Gem Notes Baryte from South Dakota, USA| Gems from Mong Long, Myanmar|Pyrite...Myanmar|Pyrite and other sulphides from Peru|Purple spinel from Badakhshan, Afghanistan| Windmill-cut topaz from Namibia|Tourmaline...Tanzania|Tsavorite from Ethiopia|Black star CZ sold as natural star rutile|Cameos at the Natural History...Kettle North East â Mark W. Houghton South East â Veronica Wetten South West â Richard M. Slater For full...pink diamonds (natural, synthetic and treated), spinel, Whatâs New corundum, alexandrite, tanzanite |
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| characteristic, flattened triangular shapes of âmacleâ spinel-law twins. Some of the crystal faces are convex...dynasty (320â298 B.C.) who regulated an active local diamond trade (Maillard, 1980). Legends associated... Figure 4. A diamond crystal in âblue groundâ from South Africa, probably from the collection of Gardner and...stream beds, possibly very far from the primary kimberlite pipes. However, some also were probably found...(Maillard, 1980); these were probably not mines in kimberlite but deep diggings in diamond-bearing conglomerates |
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| Xenoliths and Mantle Nodules Kimberlite Facies 90 Origin of Kimberlite 109 Origin of Diamond 116 References...Lamproite 139 Genesis of Lamproite in Comparison with Kimberlite 142 References 143 CHAPTER 8 PLACERS 147 Pleistocene...4 1.2 Kimberlite and lamproite fields in Brazil 7 1.3 Kimberlite fields in South Africa 8 1.4 Major...Major kimberlite sites in Russia 9 1.5 Main Russian diamond mine sites and kimberlite bodies within...within Siberian platform 13 1.6 Kimberlite fields south of the White Sea 15 1.7 Diamond placers in Venezuela |
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| discovery of these rocks in the Orange Free State of South Africa. The name is not a new one: In 1928,...kimberlites and reviews some of the advances in kimberlite petrology since 1986. The work is a critical...although current hypotheses for the genesis of kimberlite and orangeite are critically reviewed. These...3. Boshof District . . . 1.8.3.1. Roberts Victor 1.8.3.2. New Elands 1.8.4. Winburg District ... 1.8.5...Kroonstad District .. 1.8.6. Swartruggens District. 1.8.7. Dokolwayo .. 1.8.8. Prieska District 1.8.9. Summary |
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| 1093/petrology/egn034 Crystallization of Groundmass Spinel in Kimberlite P. L. ROEDER1* AND D. J. SCHULZE2 1 DEPARTMENT...ONTARIO L5L 1C6, CANADA Groundmass spinel grains in 46 kimberlite and related rocks have been analyzed...of the spinel analyses are classified as high-chromium chromite (Chr) and magnesioulvoÂŤ spinel^magnetite...significant stages of spinel growth. There are also a significant number of spinel grains that are classified...xenocryst spinel (Xen), pleonaste spinel (Ple) and magnetite (Mag). Eight different spinel zoning trends |
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| Volume 28 No.1 The abalone Haliotis rufescens Star stones January 2002 An unusual deposit in ~Kakuten'...North West - D. M. Brady, Scottish - B. Jackson, South West - R.M. Slater Examiners: A.J. A l l n u t t...23(5), 259-66 J. Gemm., 2002, 28,1, 7-12 Star garnets and star garnet cat's-eyes from Ambatondrazaka, Madagascar...ABSTRACT: Mineralogical and gemmological properties of star garnets from Ambatondrazaka, Madagascar, are given...cabochon from India, revealing a white four-rayed star. It measures 24.2 x21.5 mm, and weighs 69 ct. Photograph |
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| admittedly controversial chapter, since many textbooks state that Mogok is of "contact" metamorphic origin. No...provided the TEM photomicrographs of opal. The South Australia Department of Mines and Energy provided..., was responsible for photographs of the Argyle mine and the spectacular pink diamond. The Smithsonian...about 10 percent of the diamonds recovered from kimberlite pipes are of gem quality. In placer deposits...either side of the mouth of the Orange River in South Africa and Namibia represent millions of years of weathering |
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| admittedly controversial chapter, since many textbooks state that Mogok is of "contact" metamorphic origin. No...provided the TEM photomicrographs of opal. The South Australia Department of Mines and Energy provided..., was responsible for photographs of the Argyle mine and the spectacular pink diamond. The Smithsonian...about 10 percent of the diamonds recovered from kimberlite pipes are of gem quality. In placer deposits...either side of the mouth of the Orange River in South Africa and Namibia represent millions of years of weathering |
 | | Thesis/Dissertation |
| Geology and Gems of Mogok Area, Pyin Oo Lwin District, Mandalay Region 1 Tin Zaw Oo and 2 Nwe Ni Win...Shwebo. Politically, Mogok belongs to Pyin Oo Lwin District in the Mandalay Region. Northern boundary of the...whereas southern boundary is about 3 km S of the municipality of Mogok at about 22Ë 52' N. The Eastern boundary...in (a) extensive (regional metamorphism) and (b) local scale (contact metamorphism) (Fig. 5&6). Geologically...spinelbearing marble, spinel-chondrodite marble,spinel-graphite-phlogopite chondrodite marble, spinel-chondrodite-phlogopite |
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| (Price As. 4 or 5d.) No. 8.âManganese-ore in Bamra State. By M. S. Krishnan and P. K. Ghosh. (Price As....) No. 16.âThe Charnockite Series of tho Bastar State and Western Jeypore. By P. K. Ghosh. (Price Rs....âBauxite and Aluminous Laterite Occurrences in Jashpur State. Eastern States Agency. By A. K. Dey. (In lhe Press...Ceylon .... Kashmir .... Mining and Marketing VIII Spinel............................................. Introduction...are known as synthetic rubies, sapp hires, and spinel. They are chemically and physically identical with |
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| Geochemistry, University of Cape Town, Rondebosch, South Africa 7700 Received October 2, 1989 / Accepted January...Oxygen fugacities are calculated for olivine - spinel 4- orthopyroxene assemblages recovered from diamonds...diamonds and the concentrate of the Dokolwayo kimberlite, Swaziland. In addition thermobarometric oxygen...oxygen fugacities are obtained for chrome spinel-garnet peridotites and diamonds from several other southern...reduced conditions also suggest that the Dokolwayo kimberlite is unlikely to be a product of redox melting |
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| Gemstone and Pearl Testing 36 Emeralds from South America â Brazil and Colombia 48 Clinohumite â The...Passionate Conflict 30 Book Report 58 Terra Spinel, Terra Firma 62 66 69 72 76 80 54 4 InColor |...terms are being completed. With the support of local government authorities, the first Gembureau was...Opening a Tsavorite Mine T anzaniteOne Limited is working towards opening a tsavorite mine not far from its...Tanzania, about 20 kilometers from its tanzanite mine. The project has a total indicated resource of 1 |
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| Euclase, 2.3 cm, from the GachalĂĄ mine, GuaviĂł-GuatĂŠque mining district, BoyacĂĄ Department, Colombia. Gail...cm, from Stak Nala, Haramosh Mountains, Skardu district, Gilgit-Baltistan, Pakistan. Zach Goodman collection;...Budd photo. Tanzanite, 7.6 cm, from the Merelani mine near Arusha, Tanzania. Barry & Beth Kitt collection;...Fluorite on quartz, 13 cm, from the Yaogangxian mine, Chenzhou Prefecture, Hunan Province, China. The...Spodumene (variety kunzite), 9 cm, from the Urucum mine, GalilĂŠia, Minas Gerais, Brazil. Gus & Jane Eifler |
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| produced at Chuncheon, Korea, since 1976. As East Africa continues to yield more gems from different localities...Ch'unch'on). Annual production of the nephrite mine (the Daeil Mine) is reported to be approximately 80 000-90...map of nephrite mine area, Chuncheon, Korea. Occurrences The geology of the nephrite mine area consists...1995,24, 8 549 Fig. 3. Mine workers remove nephrite ore at the Daeil Mine, Chuncheon, Korea. The nephrite...iron present in the mineral exists in the ferrous state. This may not be so and the iron values reported |
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| Robert M. Shipley, Jr. The Chanthaburi-Trat Gem Field, Thailand Peter C. Keller 197 Gemstones with Alexandrite...Friedelite from the Kalahari Manganese Field near Kuruman, South Africa Herbert S . Pienaar Tourmaline as...the submission of articles on all aspects of the field. Please see the Suggestions for Authors for preparing...known to many of his friends in the gemological field, was a great asset to his father in the early days...father in 1933, and his expertise in the laboratory field and in the development of instrumentation for gemologists |
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| edu DIAMOND Dutoitspan Mine, Kimberley Northern Cape Province, South Africa Only in the . . . valley...Gardner F. Williams in The Diamond Mines of South Africa (1904, p. 115) T he valley referred to by...diamonds. As a child, this tale was a favorite of mine, especially as I imagined the birds to be pteranodons...prospectors then made a further offer to return to the field and bring back a few million dollars worth of diamonds...dispatched with Slack and Arnold to check out the field. A mining engineer with a reputation for exposing |
