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Oxygen isotope systematics of emerald: relevance for its origin and geological significance |
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| Authors: | G Giuliani C France-Lanord P Coget D Schwarz A Cheilletz Y Branquet D Giard A Martin-Izard P Alexandrov D H Piat |
| Institution: | ORSTOM, Institut Fran?ais de Recherche Scientifique pour le Développement en Coopération and CRPG-CNRS, UPR 9046, BP 20, 54501 Vandoeuvre-lès-Nancy Cedex, France e-mail giuliani@ crpg.cnrs-nancy.fr, FR CRPG-CNRS, UPR 9046, BP 20, 54501 Vandoeuvre les Nancy Cedex, France, FR Gübelin gemmological laboratory, Maihofstrasse 102, CH-6000 Lucerne 9, Switzerland, CH ENSG-INPL and CRPG-CNRS, UPR 9046, BP 20, 54501 Vandoeuvre les Nancy Cedex, France, FR 58 rue Charlot, 75003 Paris, France, FR Departamento de Geologia, Universidad de Oviedo, Arias de Velasco, 33005 Oviedo, Spain, ES 54 rue La Fayette, 75009 Paris, France, FR |
| Abstract: | Oxygen isotopic composition of emerald from 62 occurrences and deposits in the world reveals a wide range in δ18O (SMOW) between +6.2 and +24.7‰. The δ18O-values for each deposit are restricted and can be used to determine the origin of emerald from the world's most important producers. The δ18O-value of emerald appears to be a fingerprint of its origin, especially for gems of exceptional quality from Colombia (eastern emerald zone, δ18O = +16.8 ± 0.1‰; western emerald zone, δ18O = +21.2 ± 0.5‰), Afghanistan (δ18O = +13.5 ± 0.1‰), Pakistan (Swat-Mingora districts, δ18O = +15.7 ± 0.1‰), Brazil (Santa Terezinha de Goiás, δ18O = +12.2 ± 0.1‰; Quadrilatero Ferrifero, δ18O = +6.9 ± 0.4‰) and Zimbabwe (Sandawana, δ18O = +7.5 ± 0.5‰). Furthermore, the 18O-composition of emerald appears to be a good marker of its geological environment because the data suggest that host-rock-buffering of fluid δ18O is considerable during fluid-rock interaction. Received: 29 January 1998 / Accepted: 25 March 1998 |
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