 | | Book | | GEMSTONES of East Africa Burundi, Kenya, Rwanda, Tanzania and Uganda Bruce Cairncross Published by Struik...77584 698 7 ( ePUB) Front cover: Multifaceted tanzanite crystal, 8 cm - Marcus Bud ii Collection, Malte...specimen, Bruce Cairncross photo; (bottom) large tanzanite crystals in parallel growth, 14 cm - Desmond Sacco...resources 12 Burundi 13 Kenya 14 Rwanda 16 Tanzania 17 Uganda 20 Gemological properties 21 A to...through Tanzania, Kenya, Ethiopia and into the Sudan - has blessed East Africa, Kenya and Tanzania, with |  | | Journal (article/letter/editorial) | | Green Gem Variety of Grossular Merelani Hills, Manyara District, Tanzania G rossular, Ca3Al2(SiO4)3,...Variably colored grossular specimens from the Jeffrey mine in Canada have previously been featured as a Connoisseur’s...for this column (fig. 1) are from the Merelani Hills, Tanzania. From the standpoint of this article,...formation. They concluded that the metamorphism in the region occurred from 620 to 580 ma, coincidental with... back center specimen 2.6 cm, Merelani Hills, Manyara region, Tanzania. Patrick Meyer specimens, Jeff |  | | Journal (article/letter/editorial) | | gemmy, intense purple apatites from this pegmatite mine have made Pulsifer the premier locality for fluorapatite...” 5.6 cm tall, Alchori, Shigar Valley, Skardu district, GilgitBaltistan, Pakistan. Private collection...syenite pegmatites in the Imilchil area, High Altas Mountains, Morocco (Jahn et al. 2003); the Alpine clefts...Swan Hill Rural City, Victoria Aberfoyle mine, Rossarden district, Tasmania Complex metamorphosed sedimentary...Norte and Paraíba: e.g., Sapo mine, Ferruginha; Golconda district, Governador Valadares; Linópolis |  | | Journal (article/letter/editorial) | | 15 ORIGIN OF TANZANITE AND ASSOCIATED GEMSTONE MINERALIZATION AT MERELANI, TANZANIA C. HARRIS Department...Geological Society of South Africa ABSTRACT Tanzanite is the blue vanadium-bearing variety of zoisite...source of gem-quality tanzanite, to date, is the Merelani area of northeastern Tanzania, a structurally complex...complex region consisting of granulite facies metacarbonate and metasilicate rocks overprinted by amphibolite...The δ18O values of tanzanite, tremolite, tsavorite and kyanite from the Merelani area are all high (average |  | | Journal (issue) | | GRQ:)/' President: H. Levy Vice-Presidents: D. J. Callaghan, A. T. Collins, N. W. Deeks, E. A. Jobbins...(Petershausen), Dr J. E. Shigley (Carlsbad), Prof. D. C. Smith (Paris), E. Stern (London), Dr M. Superchi...Gerais, Brazil, which has been the most productive mine since the 1980s. Growth of alexandrite by the HOC...purchased from the Tairus company in Bangkok by Dr D. Schwarz of Lucerne, Switzerland (Figure 7 a,b). ...as twinning are ruled out as a cause (Figure 12 c,d). At present, the formation mechanism of these inclusions |  | | Journal (issue) | | of prehnite have been found, the famous Jeffrey Mine in Asbestos, Quebec, Canada. I found well-crystalized...April 2021 2 Rare prehnite crystals, Jeffrey Mine, Asbestos, Quebec, Canada. Photo: Bob Cooke. The...have contributed to the unusual colors in the Merelani deposits. Whatever the geologic cause, the result...with color choices. Prehnite on epidote, Kayes Region, Mali. Photo: Bob Cooke. China is a large country...for prehnite with associated epidote is the Kayes Region of Mali. Spheres of translucent pea green prehnite |  | | Journal (issue) | | Cindy Edelstein RETAILING IN THE NEW MILLENNIUM E d i t o r ’ s n o t e : Because of contractual restrictions...Fancy Intense purplepink diamond; (12) a 10.07 ct tanzanite in a platinum and gold ring designed by Bernd...jewelry is courtesy of Neil Lane Jewelry, Beverly Hills, California. Photo © GIA and Tino Hammid. G EMS...made it possible to recover diamonds from the Ekati mine, in the bitter cold of Canada’s Northwest Territories...diamond reserves, and future potential. The new Ekati mine in Canada’s frigid Northwest Territories, Namdeb’s |  | | Journal (issue) | | James E. Shigley Andy Lucas Donna Beaton Stuart D. Overlin Nathan Renfro Elise A. Skalwold John I....etching, in quartz crystals from India’s Jalgaon District. NOTES AND NEW TECHNIQUES 82 Characteristics...Magnesio-axinite from Tanzania • Sustainable vertical integration in sapphires • Freeform tanzanite and sunstone...Robert Weldon survey Brazil’s diamond deposits. This region has produced a significant number of large rough...Omi regions of Niigata Prefecture and the Wakasa region of Tottori Prefecture and compares them with samples |  | | Journal (issue) | | jewelry indrrstry In fi~tingtribute, this 89.01-ct D-internally flawless modified shield cut- the Guinea...rcpublication permission, please contact the editor. Gems d Gemology is published quarterly by the Gemological... Postmaster: Return undeliverable copies of Gems d Gemology to 1660 Stewart St., Santa ~Monica,CA 90404...EDITORIAL STAFF Associate Editors William E. Boyajian D. Vincent Manson John Sinkanltas Technical Editor Carol...equal pride that we present in this issue of Gems d Gemology a very special pre-Symposium section including |  | | Book | | (field of view 8 cm). Figure 1.3 An opencast iron ore mine (Postmasburg, South Africa). 7 microscopes, or...which are essentially spherical (figure 2.3A), and p, d and f orbitals (figure 2.3B, C), which are shaped...three equivalent orbitals occupied by electrons, the d as a set of five and the f as a set of seven orbitals...orbitals (A) (B) y x x y z z z The five d orbitals (D) (C) y x x y z Figure 2.3 The shapes and...and arrangement of the (A) s, (B) p and (C) d orbitals. The seven f orbitals are extremely complex and |  | | Journal (issue) | | Science LLC, Tokyo, Japan Executive Editor Alan D. Hart Editorial Assistant Carol M. Stockton Editor...Harvard University, Cambridge, Massachusetts, USA Alan D. Hart Gem-A, London Karl Schmetzer Petershausen,...MEMBER Martin Rapaport CHIEF EXECUTIVE OFFICER Alan D. Hart COUNCIL Justine L. Carmody – Chair Nevin Bayoumi-Stefanovic...carbon footprint of each individual diamond’ from its mine origin to the polished gem. The data can 642 THE...locality (Figure 5) in central China: the Qinling Mountains in Zhen’an County, Shaanxi Province, where they |  | | Journal (issue) | | (British Omineca Columbia) Vitim East Sayan Mountains Lillooet (California) CHINA Nanjiang Luchuan...Nelson North Westland South Westland Livingstone Mountains NEW ZEALAND Wakatipu Figure 1: Nephrite jade...composition: some Pacific Rim examples a b c d Figure 2: Nephrite jades of similar appearance from...from the Pacific Rim: (a) East Sayan Mountains, Siberia, Russia, (b) Olderog Creek, North Westland, New...uniform textures; (c) South Westland, New Zealand; (d) Cassiar, British Columbia. These examples do contain |  | | Journal (article/letter/editorial) | | A. P06 2.1.MO .139 Structure of methyl 6-deoxy-a-D-idopyranoside Bryan R. F., Carey F. A., Hartley P...Mayoral J. A., Cativiela C, Diaz de Villegas M. D., Ajô D., De Zuane F. P08 2.1.MO .141 Bile salts: From...molecular structure of leucinostatin A Cerrini S., Lamba D., Ughetto G. P10 2.1.MO .143 Structure of a rigid..., Zbinden P., Dobler M., Benner S. A., Dunitz J. D. P16 2.1.MO .149 The crystal structure of [18]-crown-6...M., Rebrova O. N., Biyushkin V. N., Protsenko L. D. P25 2.1.MO .'..158 New data about polymorphism of |
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D-Block Mine, Merelani Hills, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania