 | Giuliani, Gaston, Fallick, Anthony, Rakotondrazafy, Michel, Ohnenstetter, Daniel, Andriamamonjy, Alfred, Ralantoarison, Théogène, Rakotosamizanany, Saholy, Razanatseheno, Marie, Offant, Yohann, Garnier, Virginie, Dunaigre, Christian, Schwarz, Dietmar, Mercier, Alain, Ratrimo, Voahangy, Ralison, Bruno (2007) Oxygen isotope systematics of gem corundum deposits in Madagascar: relevance for their geological origin. Mineralium Deposita, 42 (3) 251-270 doi:10.1007/s00126-006-0105-3 | Journal (article/letter/editorial) | | Oxygen isotope systematics of gem corundum deposits in Madagascar: relevance for their geological origin...Abstract The oxygen isotopic composition of gem corundum was measured from 22 deposits and occurrenEditorial...d’Antananarivo, Ambohitsaina, BP 906, Antananarivo 101, Madagascar Y. Offant Cerege, Europole Méditerranéen de l’Arbois...Ambaranjana Antanimora, Antananarivo 101, Madagascar ces in Madagascar to provide a gemstone geological identification...identification and characterization. Primary corundum deposits in Madagascar are hosted in magmatic (syenite and |  | Giuliani, Gaston, Fallick, Anthony E., Feneyrol, Julien, Ohnenstetter, Daniel, Pardieu, Vincent, Saul, Mark (2011) 18O/16O and V/Cr ratios in gem tsavorites from the Neoproterozoic Mozambique metamorphic belt: a clue towards their origins?. Mineralium Deposita, 46 (7) 671-676 doi:10.1007/s00126-011-0355-6 | Journal (article/letter/editorial) | | from northern and southern Tanzania, Kenya, and Madagascar. Three consistent sets of δ18O values between...tsavorite deposits are found in Kenya, Tanzania, and Madagascar. The geology of the deposits has been studied...tsavorite of 4.58 carats from the Merelani mining district. Photograph from Swala gem traders (on the left...tsavorite from the Nadan I mine in the Voi mining district (Kenya). The width of the photograph is 8 cm....geological and/or geographical origins of emerald and corundum (e.g., Giuliani et al. 2005). The aim of this |  | | Journal (issue) | | occurrence of vanadian grossular garnet from Madagascar A. Mercier1,2, B. Moine2, J. Delorme3 and M.A...Antananarivo, Madagascar 4 Service de Géologie, Université de Tananarive, B.P 906, Antananarivo, Madagascar ABSTRACT:...occurrence of vanadian grossular garnet from Madagascar is described. Its composition is similar to grossulars...Figure 1: The Gogogogo tsavorite occurrence Vanadian grossular garnet of gemin Madagascar. quality (tsavorite)...of 1991 in the Gogogogo area of south-western Madagascar, about 40 km north of Ampanihy (Figure 1) and |  | 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) | | Published: 30 June 2020 Abstract: Corundum is not uncommon on Earth but the gem varieties...of ruby and sapphire are relatively rare. Gem corundum deposits are classified as primary and secondary...secondary deposits. Primary deposits contain corundum either in the rocks where it crystallized or as xenocrysts...the Earth’s surface. Classification systems for corundum deposits are based on different mineralogical...magmatic) origin are hosted by alkali basalts (Madagascar and others), and Type IB corresponding to xenocrysts |  | Boger, S.D., Hirdes, W., Ferreira, C.A.M., Jenett, T., Dallwig, R., Fanning, C.M. (2015) The 580–520Ma Gondwana suture of Madagascar and its continuation into Antarctica and Africa. Gondwana Research, 28 (3) 1048-1060 doi:10.1016/j.gr.2014.08.017 | Journal (article/letter/editorial) | | The 580–520 Ma Gondwana suture of Madagascar and its continuation into Antarctica and Africa...Fanning, C.M., The 580–520 Ma Gondwana suture of Madagascar and its continuation into Antarctica and Africa...MANUSCRIPT The 580–520 Ma Gondwana suture of Madagascar and its PT continuation into Antarctica and...ABSTRACT SC RI U–Pb age data from southwest Madagascar provides a compelling case that the pre-Gondwana...continuity across the suture. In southwest CE Madagascar the distribution of metamorphic ages places the |  | | Journal (article/letter/editorial) | | reserved. 1. Introduction Ruby is a red variety of corundum, Al2O3. The color is due to isomorphous replacement...as amphibolite, serpentinite (e.g., Gogogogo and Ejeda, Madagascar); (3) rubies in desilicated pegmatites...(2005). calcite and spinel and between calcite and corundum (ruby) all give unreasonable temperatures, exceeding...relations employed for calcite–spinel and calcite–corundum pairs were those calculated by the incremental...that O-isotope fractionation between calcite and corundum is 3.80 ± 0.15‰ at 607 ° ± 15 °C. Following the |  | | Book | | studies, namely ruby, the red-colored gem variety of corundum. The color results from a sufficiency of the trace...Wang, K.; Tarantola, A.; Zaw, K.; Meffre, S. Gem corundum deposits of Greece: Geology, Mineralogy and Genesis...Griffin, W.L.; Saunders, M.; Toledo, V. Chromium in Corundum: Ultra-high Contents under Reducing Conditions...new research territory [8–13]. Research into gem corundum, however, is a continuing process, and new aspects...that determine the spectrum of colors seen in gem corundum shows that their combined individual effects can |  | | Journal (issue) | | courtesy of Rio Tinto; (4) an 11.16 ct sapphire from Madagascar, GIA Collection no. 31618; (5) a 1.01 ct yellow...competitive rough diamond market. Political problems in Madagascar and a ban on gem exports from Myanmar disrupted...were combined under the jurisdiction of the U.S. District Court of New Jersey 168 PRODUCTION AND MARKETS...for gemstones. New Deposits and New Operations. Madagascar. Much of the global gem business for well over...in the middle of the decade was dominated by Madagascar. This was due in part to the Malagasy PRODUCTION |  | | Thesis/Dissertation | | ............. 22 2.5.3.1.2.5. Antetezambato, Madagascar ........................................................................... 27 2.5.4.1.1.3. Madagascar ................................................................... 40 2.5.9.1.1.2. Bekily, Madagascar ........................................................................... 42 2.5.9.2.2.2. Madagascar ................................................................. 42 2.5.9.2.2.3. Tranoroa, Madagascar............................................. |  | | Journal (issue) | | Kenya, Zimbabwe, Nigeria, and Namibia, as well as Madagascar), South America (Brazil and Colombia), central...Myanmar (Burma); blue and pink sapphires from Madagascar; a wide variety of colored stones from southern...small stones (0.05 to 1 ct) of high quality. Madagascar and Zambia tend to produce cleaner but slightly...were Nigeria, Mozambique (figure 3), Zambia, and Madagascar. In particular, the availability from Zambia...from the Ilakaka alluvial deposit in southern Madagascar. Toward the end of the decade, sources in India |  | | Journal (issue) | | the blue sapphire are one a n d the same mineral—corundum, a n d that a n impure form of the same mineral...have been Sanskrit. PROPERTIES T h e mineral corundum, of which ruby and sapphire are the most highly...ruby, and the oxides of titanium and iron give to corundum the rich blue which alone can be seen in the lovely...variety, ruby crystals usually showing Group of corundum crystals. 103 a different habit from that of...usually opaque, crystals from Tanganyika and Madagascar. I n m a n y crystals the prisms are very m u |  | | Journal (issue) | | resembles greenish-blue aquamarine from Tongafeno (Madagascar) but also contains three-phase inclusions like...two papers reflect the growing importance of Madagascar and describe features of sapphires from a new...looked very similar to aquamarine from Tongafeno, Madagascar (Figure l), 1 but which had different physical... 6 Apart from the aquamarine from Tongafeno, Madagascar, which it resembles in appearance, there are...Medium-dark blue aquamarines from Tongafeno, Madagascar, with high physical and optical properties, and |  | | Journal (issue) | | 32 NO. 2 T A B L C O N T E N T S EDITORIAL Madagascar: Making Its Mark Richard T. Liddicoat FEATURE...ARTICLES Sapphires from the Andranondambo Region, Madagascar Dietmar Schwarz, Eclzehard I. Petsch, and Tan...new find of gem blue sapphires on the island of Madagascar. Over the years, we have come to think of Sri...Sri Lanlza as the gem island, but Madagascar certainly vies with it in the variety of fine-quality gem...this volume refers to Sri Lanlza 28 times and to Madagascar, 24 times. Both islands are underlain by ancient |  | | Journal (issue) | | Iran|Purple apatite from Namibia|Cordierite from Madagascar|Emerald and pyrite mixture from Colombia|Garnet...Colombia|Garnet from Mahenge, Tanzania|Grandidierite from Madagascar|Lalique quartz pendant in polarized light|Faceted...Malecka Gemmological Brief 64 A Lead-Glass-Filled Corundum Doublet By Supparat Promwongnan, Thanong Leelawatanasuk...low-temperature treatment) and Madagascar (Andilamena); sapphires from Madagascar (Andranondambo), Nigeria...Orange-Red to Yellowish Brown Cordierite from Madagascar Gem-quality cordierite is typically seen as blue |  | | Journal (issue) | | emmoi emmoi emmoi Volume 27 No. 7 July 2001 Madagascar gems • Type II diamonds • Describing gems he... New gemstone occurrences in the south-west of Madagascar Dr Claudio C. Milisenda1, Dr Ulrich Henn2 and...were discovered in the south-western part of Madagascar. The secondary deposits extend from the south...yellow, orange, green, pale brown and colourless corundum varieties, spinels, chrysoberyls, garnets, aquamarines...Lanka. In addition a number of pinkish-orange corundum varieties show colours and absorption spectra |  | | Journal (issue) | | beryl (SP) ? HyS 128 129 131 129 141 144 130 Corundum: ruby, blue sapphire and other colours Verneuil...Verneuil/Baikovsky/France 1942 Ruby L Merker/Linde/USA 1947 Star corundum Linde/USA Linde/USA 1960 Ruby discs (SP) FR Charvat/Linde/USA...chalcedony and agate), thermally treated gems (such as corundum and zircon) and radioactively irradiated gems...rough and cut materials from different stages of corundum production were obtained through Pinky Trading...hydrothermal process for the production of synthetic corundum was patented by Bell Telephone Laboratories, US |  | | Journal (issue) | | However, the application of of uniaxial gem minerals corundum, beryl and quartz, as an immersion microscope...of the value and demand of the gem varieties of corundum (ruby, sapphire) as well as beryl (emerald, aquamarine)...Table 1: Selected crystal faces and angles of corundum, n: - Ah03, a—A1 D3d ~ —33~^ 203, trigonal, crystal...in the three important important gem minerals corundum, beryl and quartz, which are used as examples...addition to these crystal faces, the minerals corundum corundum and beryl normally reveal the basal pinacoid |  | | Journal (issue) | | the Ndola Rural Protected Area of the Lufwanyama district in the Copperbelt Province of Zambia. The Ndola...2002. The Santa Terezinha-Campos Verdes emerald district, central Brazil: structural and Sm-Nd data to...spinels are known from Tanzania, Sri Lanka and Madagascar (e.g. see Modern Jeweler). The gem-quality spinels...Myanmar (Mogok and Namya), Vietnam (Luc Yen area), Madagascar (Ilakaka region), Tajikistan (Pamir Mountains:...Palaeozoic metasedimentary schists and marbles corundum and spinel deposits faults Palaeo-Mesoproterozoic |  | | Journal (issue) | | result of a several weeks stay at Matara, which gem district he visited in response to an urgent request for...alluvial gemstone than the ruby or sapphire. The corundum crystals of these gravels commonly display small...second order prisms and the bipyramid but not of a corundum Gemm., 1991,22,8 J. Gemm, 1991,22,8 467 crystal...are utilized here (Klaproth, 1801). Thus, on on corundum, or "oriental sapphire", sapphire'~ Klaproth disputes...identical to currently accepted analyses for for corundum. From and other comparisons with the the analyses |  | | Book | | Neuerdings sollen größere Rubinfunde in der Gegend von Gogogogo im Süden Madagaskars gemacht worden sein (Behier...832-836. Altherr, R., Okrusch, M. & Bank, H. (1982): Corundum- and kyanite-bearing anatexites from the Precambrian...Observations of Dislocations and Surface Features in Corundum by Electron Transmission Microscopy. - J. Research...Contribution a la Mineralogie de Madagascar. - Ann. Geol. de Madagascar 29: 1-78. Belt, R. F. (1967): Hydrothermal...-216. Brown, G.· (1984): Inclusions in Synthetic Corundum by Chatharn. - Austral. Gemm. IS: 149-154. Burch |  | | Journal (issue) | | FEATURE ARTICLES 166 Benitoite from the New Idria District, San Benito County, California Brendan M. Laurs...Benitoite Gem mine, the geology of the New Idria district and current mining there, and the gemological...Fall 1997 165 BENITOITE FROM THE NEW IDRIA DISTRICT, SAN BENITO COUNTY, CALIFORNIA By Brendan M. Laurs...world, the Benitoite Gem mine in the New Idria district of San Benito County, California. A barium titanium...from only one region in the world, the New Idria district of San Benito County, California. Benitoite was |  | | Book (edition) | | extensive fields in the prophetically named Kimberley district of Western Australia promise to be of world importance...minerals), and temperatures were high enough, corundum and spinel may form, and this may be how ruby...applied in countries such as Brazil (Figure 1.29), Madagascar and Sri Lanka, almandine garnet, aquamarine,...Mining Kimberlite at the Majhgawan deposit, Panna District, Madhya Pradesh, India one of a variety of underground...characteristics may come from East Africa (ruby), Madagascar 37 The Geological Sources of Gems (sapphire) |  | | Journal (issue) | | commonly mixed with imported rough from Ilakaka, Madagascar. However, at the time of writing (March 2007)...the laboratory of the Institut de Gemmologie de Madagascar in Antananarivo (T. Ramerison, pers. comm., 2006)...possibility that a few stones could come from Madagascar. We are sure that none of the stones comes from...some gem minerals in Sri Lanka: evidence from corundum-spinel-scheelitetaaffeite-bearing rocks. In: Rammlmair...New gemstone occurrences in the south-west of Madagascar. Journal of Gemmology, 27(7), 385-94 Nuber, B |  | | Journal (issue) | | p.BCr1 GIA G&G Spring ʻ11 Journal #20183-0 Madagascar Demantoid Andesine and Zircon from China Vietnamese...Demantoid and Topazolite from Antetezambato, Northern Madagascar: Review and New Data Federico Pezzotta, Ilaria...northeastern China. 42 Aquamarine from the Thuong Xuan District, Thanh Hoa Province, Vietnam Le Thi-Thu Huong...near the village of Antetezambato, in northern Madagascar, emerged as an important source of demantoid... The Bulgari necklace in white gold features Madagascar demantoid (107.47 carats total weight), round |  | | Book (edition) | | 16"-century Germany, fire setting is still used in Madagascar mined and transformed into jewellery within...Sapphire Peridot Ruby Tsavorite Fancy Sapphire MADAGASCAR Alexandrite Amethyst MOZAMBIQUE Apatite Aquamarine...oxides and hydroxides) and mineral families (e.g. Corundum, Beryl and Feldspar). Howlite Sinhalite se ...Chrysoberyl - Chrysoberyl Vanadium Chrysoberyl Corundum Ruby Tanzanian Ruby - Star Ruby Sapphire...Tanzania’s Umba Valley (1987), Bekily in southern Madagascar (late 90s) and most recently (January 2009) |
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Gogogogo, Gogogogo, Ampanihy District, Atsimo-Andrefana, Madagascar