 | | Journal (article/letter/editorial) | | sapphire-zircon-magnetite xenolith from the Chanthaburi Gem Province, Thailand ROBERTR. COENRAADS The Gemmological Association...Mineral Resources, Rama 6 Road, Bangkok 10400, Thailand AND F. [.IN SUTHERLAND Division of Earth and...magnetite-bearing xenolith from Khao Wua, near Chanthaburi in Thailand, conclusively demonstrates a common origin for...magnetite found in alluvial deposits in the Chanthaburi gem fields. The original aluminium- and titanium-rich...zircons (2.57 ___0.20 Ma) from the Chanthaburi-Trat gem fields and within the potassium-argon ages of 0.44 |  | | Journal (issue) | | Blanche of Lancaster Black Spinel from Thailand Camera-Drone Gem Exploration Volume 37 / No. 1 / 2020...Report 2019 | Gold Demand Trends 2019 | ID of Green Gems with Portable Instruments | The Journal’s Cumulative...| Maine (USA) Mineral & Gem Museum Gem Notes Hessonite from Kunar Province, Afghanistan | Olshanskyite...of Light Brown Melee | Multicoloured Synthetic Corundum and Multicoloured Glass Doublets | Imitations...26–64 of this issue describes its history and the gems it contains, which consist of blue and pink sapphires |  | | Journal (issue) | | Franks, B.Sc., Ph.D., F.G.A. South Yorkshire & District Branch: J. L Platts, F.G.A. Examiners: E. A. Jobbins...Dt.Gemmol.Ges., 23, 3, 178-9. Webster, R. (1975): Gems—Their Sources, Descriptions and Identification,...INTENSIVE YELLOW TSILAISITE (MANGANESE TOURMALINE) OF GEM QUALITY FROM ZAMBIA By Dr KARL SCHMETZER* and Prof...†Idar-Oberstein, West Germany ABSTRACT Transparent gem tourmalines with an intensive yellow coloration from...members of the series dravite-uvite. In both groups of gem tourmalines small amounts of iron, i.e., small percentages |  | | Journal (article/letter/editorial) | | Road, Khlong Toey Nua, Watthana, Bangkok 10110, Thailand *Corresponding author, e-mail: seriwat@hotmail...inclusions and coexisting minerals of gem corundum from the Thailand area analysed by SEM-EDS in this study...mineral, inclusion, chemistry, SEM-EDS, corundum, ruby, sapphire, Thailand, origin. 1. Introduction Sutherland...stage. However, corundum is known as inclusions in diamond (Hutchison et al., 2004). Corundum from basaltic...eastern Thailand. Garland et al. (2001) in a study of Montana sapphires discussed two corundum groups |  | Peucat, J.J., Ruffault, P., Fritsch, E., Bouhnik-Le Coz, M., Simonet, C., Lasnier, B. (2007) Ga/Mg ratio as a new geochemical tool to differentiate magmatic from metamorphic blue sapphires. Lithos, 98 (1) 261-274 doi:10.1016/j.lithos.2007.05.001 | Journal (article/letter/editorial) | | reserved. Keywords: Trace elements; ICP-MS–LA; Corundum; Magmatic sapphires; Metamorphic sapphires 1...trace elements can act as the signature of a single gem-deposit as did oxygen isotope composition (Yui et...Spectroscopy (LIBS). Therefore, the measurement of Mg in corundum, which is generally not obtained, may help to...investigations. 2. General setting and previous works Corundum, which consists of more than 98% of Al2O3, contains...elements such as V, Ga and Mg are also present in corundum, but in lesser amounts. Knowing the precise concentration |  | Yui, Tzen-Fu, Wu, Chao-Ming, Limtrakun, Phisit, Sricharn, Weerapan, Boonsoong, Apichet (2006) Oxygen isotope studies on placer sapphire and ruby in the Chanthaburi-Trat alkali basaltic gemfield, Thailand. Lithos, 86 (3) 197-211 doi:10.1016/j.lithos.2005.06.002 | Journal (article/letter/editorial) | | the Chanthaburi-Trat alkali basaltic gemfield, Thailand Tzen-Fu Yui a,*, Chao-Ming Wu b, Phisit Limtrakun...Science, Chiang Mai University, Chiang Mai 50200, Thailand Received 6 April 2005; accepted 8 June 2005 Available...(C-T) alkali basaltic gemfield in southeastern Thailand. Sapphires have O-isotope composition in the range...4.8x to +5.0x, demonstrating that the C-T placer gem corundums cannot be phenocrysts of these basalts...sub-continental mantle as the primary source for these placer gem corundums is tentatively proposed. The surface distribution |  | | Journal (issue) | | 7 July 2003 The Gemmological Association and Gem Testing Laboratory of Great Britain ~ ~~ . •~..., ~ '.~ ,:~ , Gemmological Association and Gem Testing Laboratory of Great Britain 27 Greville Street...(Figure 1) were purchased by a German gem merchant in northern Thailand and were said to originate from Myanmar...Myanmar by local dealers. During further trips to Thailand, our supplier was able to obtain some similar...photo by M. Glas. © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355-4565 |  | Graham, Ian, Sutherland, Lin, Zaw, Khin, Nechaev, Victor, Khanchuk, Alexander (2008) Advances in our understanding of the gem corundum deposits of the West Pacific continental margins intraplate basaltic fields. Ore Geology Reviews, 34 (1) 200-215 doi:10.1016/j.oregeorev.2008.04.006 | Journal (article/letter/editorial) | | o r ev Advances in our understanding of the gem corundum deposits of the West Pacific continental margins...greatly increased our knowledge of the basalt-derived gem sapphire–ruby–zircon deposits. In this paper we focus...also critically review existing data on the gem corundum deposits, in order to further refine a model...origin. In some of the intraplate basaltic fields, corundum-bearing xenoliths have been found showing a range...some fields produced a simple eruptive and zircon/corundum crystallization event while others had multiple |  | Piilonen, Paula, Sutherland, F., Danišík, Martin, Poirier, Glenn, Valley, John, Rowe, Ralph (2018) Zircon Xenocrysts from Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Southeast Asia—Trace Element Geochemistry, O-Hf Isotopic Composition, U-Pb and (U-Th)/He Geochronology—Revelations into the Underlying Lithospheric Mantle. Minerals, 8 (12) 556 doi:10.3390/min8120556 | Journal (article/letter/editorial) | | Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Article Southeastfrom Asia—Trace ElementBasalts...(U-Th)/He the Ratanakiri Volcanic Composition, Province (Cambodia), Geochronology—Revelations intoO-Hf...Zircon xenocrysts from alkali basalts in Ratanakiri Province, Cambodia represent a unique low-Hf zircon from...Abstract: Zircon xenocrysts alkali basalts Ratanakiri Province, Cambodia represent a unique low-Hf zircon ({100}...xenocryst; alkali basalt; Ratanakiri Volcanic Province; trace elements; O-isotopes and Hf-isotopes; U-Pb; |  | | Journal (article/letter/editorial) | | 92008, SC *aaron.palke@gia.edu Montana Bureau of Mines and Geology, Montana Tech, 1300 West Park Street...their melt inclusions 59701 MA ABSTRACT Gem corundum (sapphire) has been mined from an ultramafic...troctolite precursor. These calculations suggest that corundum can form through peritectic melting of kyanite... 1 ACCEPTED MANUSCRIPT Keywords: sapphire; corundum; melt inclusions; lamprophyre; liquid immiscibility;...central Montana has produced exceptional gem- SC quality corundum (sapphire) for more than 100 years. Discovered |  | | Journal (issue) | | diffraction analyses were carried out. The inclusions Corundum appears in Kenya as patches in metarecognized...inclusions responsible 1947). The same applies to the corundum of the for the asterism are separated into micro-striae...sometimes fractured. In the North-Western region, corundum is Introduction found in Tertiary volcanic olivine...been known to produce district of the Northern Rift Valley Province, and corundum in all possible colours...northwards through the Sudan appeared on the Kenyan gem market of which and Ethiopia (Bridges, 1982). some |  | | Journal (issue) | | Association and Gem Testing Laboratory of Great Britain The Gemmological Association and Gem Testing Laboratory...3334 l Fax: +44 (0)20 7404 8843 e-mail: information@gem-a.info l Website: www.gem-a.info President: E A Jobbins...very likely also be © Gemmological Association and Gem Testing Laboratory of Great Britain ISSN: 1355-4565...for alexandrite effect. Alexandrite effect (AE) Gem minerals changing colour between daylight and incandescent...first observed in a mineral found in the emerald mines at Tokowaia in the Urals (Wörth, 1842; Kokscharow |  | | Journal (article/letter/editorial) | | Guo ? Suzanne Y. O’Reilly William L. Griffin Corundum from basaltic terrains: a mineral inclusion approach...Abstract This paper investigates the origin of corundum megacrysts that occur in many basaltic terrains...for over 80 primary mineral inclusions within corundum megacrysts are used to gain a new insight into...of the corundum megacrysts. A wide spectrum of minerals is present as inclusions in the corundum; the most...minerals from corundum occurring in widely separated areas suggests that the corundum megacrysts in basalts |  | | Conference Proceedings | | term cultured pearl. Experts from various European gem testing laboratories were invited to attend a series...per country; this member being the Director of a Gem Testing Laboratory, or a gemmologist of the calibre...Stellenboch (1991), Paris, France (1993); Bangkok, Thailand (1995); Idar Oberstein, Germany (1997); Goa, India...Spain, Sri Lanka, Switzerland, Sweden, Tanzania, Thailand, U.S.A., Vietnam and Zimbabwe. During the 20th...14:40 Alessandra Costanzo , Martin Feely: Review gem-materials from Connemara, Western Ireland. 14:40 |  | | Journal (issue) | | JOURNAL OF THE GEMOLOGICAL INSTITUTE OF AMERICA Gem Art of the Taj Mahal and the Mughal Era Characteristics...Inclusions in Corundum from Bo Welu, Thailand Fall 2019 VOLUME 55, No. 3 EDITORIAL 293 Gem Art of the...Black Diamonds, and Unique Inclusions in Thai Corundum Duncan Pay FEATURE ARTICLES p. 309 294 Gemstones...Chris L. Rogers, and Robert Weldon A look at the gem ornamentation of this landmark, as well as the jewels...in Ruby and Sapphire from the Bo Welu Gem Deposit in Chanthaburi, Thailand Supparat Promwongnan and Chakkaphan |  | | Journal (article/letter/editorial) | | AND GEOCHEMISTRY OF THE DENCHAI BASALT, NORTHERN THAILAND SANDRA M. BARR Department of Geology, Acadia University...northern Thailand is part of a large continental alkalic basaltic province extending through Thailand into...basanite. The basanite is the probable source of gem-quality zircon and sapphire mined from placer deposits...f about 70 km 2 south o f Denchai in northern Thailand (Fig. 1). These basalts are part o f a large Late...Late Cenozoic continental basaltic province extending through Thailand, Kampuchea, Laos, and Vietnam. Petrologic |  | Baldwin, L. C., Tomaschek, F., Ballhaus, C., Gerdes, A., Fonseca, R. O. C., Wirth, R., Geisler, T., Nagel, T. (2017) Petrogenesis of alkaline basalt-hosted sapphire megacrysts. Petrological and geochemical investigations of in situ sapphire occurrences from the Siebengebirge Volcanic Field, Germany. Contributions to Mineralogy and Petrology, 172 (6) doi:10.1007/s00410-017-1362-0 | Journal (article/letter/editorial) | | although basalt is not generally normative in corundum. Most of these sapphire occurrences are located...Carbonatite Introduction Sapphire and ruby are gem varieties of corundum (α-Al2O3) and belong to the most prominent...along with diamond and emerald. Deposits of gem-quality corundum are well distributed around the world (e...1997). A review of the literature on gem corundum shows that corundum occurs in various geological settings...broad variability in the depositional type of corundum, Simonet et al. (2008) established a classification |  | | Book | | r· Butterworths Gem Books Edited by Peter G. Read Amber Helen Fraquet Beryl John Sinkankas and Peter...Peter G. Read Corundum Richard W. Hughes Garnet John D. Rouse Jet Helen Muller Pearls: natural, cultured...Huddlestone Topaz D. B. Hoover Butterworths Gem Books Corundum Richard W. Hughes Executive Vice President...Asian Institute of Gemological Sciences, Bangkok, Thailand Butterworth-Heinemann London Boston Singapore...in Publication Data Hughes, Richard, W. Corundum. 1. Corundum I. Title 553.8'4 ISBN 0-7506-1006-9 Library |  | | Journal (article/letter/editorial) | | range of environments and conditions involved in corundum (Al2O3) formation. We compiled a global data base...2017 Introduction Sapphire and ruby are gem varieties of corundum (αAl2O3): rubies are red, and sapphires...plate tectonic processes (Stern et al. 2013). These gems are concentrated in SE Asia (Yui et al. 2006; Khamloet...Rakotosamizanany et al. 2014). Geochemical investigations of corundum are somewhat restricted in scope because only...zone; continental collision crystal structure of corundum (e.g. Wong et al., 2017), but oxygen isotope ratios |  | | Journal (article/letter/editorial) | | of basalt-hosted corundum, particularly the role that the mantle plays in corundum generation. Some previous...Ga/Mg) are useful for distinguishing two types of corundum: ‘magmatic’ and ‘metamorphic’, designations that...regarding previous classifications that ascribe corundum from basalt-hosted gemfields to either ‘magmatic’...long-lived convergent margin suggests a link between corundum formation and Al-enrichment of the mantle wedge...R D S : trace-element geochemistry, LA–ICP–MS, corundum, sapphire, ruby, eastern Australian gemstone belt |  | 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) | | Abstract: Corundum is not uncommon on Earth but the gem varieties of ruby and sapphire...sapphire are relatively rare. Gem corundum deposits are classified as primary and secondary deposits. Primary...Primary deposits contain corundum either in the rocks where it crystallized or as xenocrysts and xenoliths...the Earth’s surface. Classification systems for corundum deposits are based on different mineralogical...specifically Type IA where xenocrysts or xenoliths of gem ruby of metamorphic (sometimes magmatic) origin are |  | Palke, Aaron C., Wong, Jacqueline, Verdel, Charles, Ávila, Janaína N. (2018) A common origin for Thai/Cambodian rubies and blue and violet sapphires from Yogo Gulch, Montana, U.S.A.?. American Mineralogist, 103 (3) 469-479 doi:10.2138/am-2018-6164 | Journal (article/letter/editorial) | | with rubies from the Chantaburi-Trat region of Thailand and the Pailin region of Cambodia. The similarities...and Yogo sapphires suggest a common origin for gem corundum from both deposits. Specifically, we advance...lamprophyre or basalts that transported the gem corundum to the surface partially melted Al-rich lower...them to the surface. The similarities in these gem corundum deposits suggests that the partial melting,...previously realized. Importantly, in both cases the gem corundum has an ostensibly “metamorphic” trace element |  | | Journal (issue) | | Phillips and Anatoly S. Talantsev Opal from Shewa Province, Ethiopia Mary L. Johnson, Robert C. Kammerling...and John I. Koivula REGULAR FEATURES Gem Trade Lab Notes Gem News Thank you, Donors Book Reviews Gemological...Guidelines for Authors ABOUT THE COVER: Perhaps no gem material in modern times carries the mystique of...Communist Russia, however, demantoids-like other gems-fell out of favor. With virtually no mining for...Pelt-Photographers, Los Angeles, CA. Color separations for Gems & Gemology are by Effective Graphics, Compton, CA |  | | Journal (issue) | | and G u o Jingfeng REGULAR FEATURES Gem Trade Lab Notes Gem News Book Reviews Gemological Abstracts...Pelt-Photographers, Los Angeles, CA. Typesetting for Gems & Gemology is by Scientific Composition, Los Angeles...Japanese translation of Gems o) Gemologx contact the Association of Japan Gem Trust, Okachimachi Cy Bldg...Taito-ku, Tokyo 110, Japan. MANUSCRIPT SUBMISSIONS Gems eJ Gemology welcomes the submission of articles...editor for a copy. Letters on articles published in Gems d Geniology and other relevant matters are also |  | | Journal (issue) | | EDITORIAL The 1980s in Review: New Realities of the Gem and Jewelry Industry Richard T Liddicoat and W i...Boyajian Thank You! Alice S. Keller FEATURE ARTICLES Gem Localities of the 1980s J a m e s E. Shigley, Dona... K o i v ~ ~ l a n, d Robert E. Kane Synthetic Gem Materials in the 1980s Kurt Nassau New Technologies...Misiorowski REGULAR FEATURES Gem Trade Lab Notes Gem News Most Valuable Article Award Gems & Gemology Challenge...PeltÑPhotographers Los Angeles, C A . Typesetting for Gems &. Gernology i s b y Scientific Composition, Los |
|
