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Published December 2003 | public
Journal Article

Pezzottaite from Ambatovita, Madagascar: A New Gem Mineral

Abstract

Pezzottaite, ideally Cs(Be_2Li)Al_2Si_6O_(18), is a new gem mineral that is the Cs,Li–rich member of the beryl group. It was discovered in November 2002 in a granitic pegmatite near Ambatovita in central Madagascar. Only a few dozen kilograms of gem rough were mined, and the deposit appears nearly exhausted. The limited number of transparent faceted stones and cat's-eye cabochons that have been cut usually show a deep purplish pink color. Pezzottaite is distinguished from beryl by its higher refractive indices (typically n_o=1.615–1.619 and n_e=1.607–1.610) and specific gravity values (typically 3.09–3.11). In addition, the new mineral's infrared and Raman spectra, as well as its X-ray diffraction pattern, are distinctive, while the visible spectrum recorded with the spectrophotometer is similar to that of morganite. The color is probably caused by radiation-induced color centers involving Mn^(3+).

Additional Information

© 2003 Gemological Institute of America. The authors are grateful to Dr. Federico Pezzotta (Natural History Museum, Milan, Italy) for supplying detailed information on the geology, mineralogy, and morphology of pezzottaite. The senior author is indebted to Dr. Pezzotta for guiding his visit to the mine in July 2003. We thank the following gem dealers for loaning and/or donating research samples: Mark Kaufman of Kaufman Enterprises, San Diego, California; Dudley Blauwet of Dudley Blauwet Gems, Louisville, Colorado; Laurent Thomas of Polychrome France Co., Chambray-lès-Tours, France; Denis Gravier and Fabrice Danєt of Le Mineral Brut, Saint-Jean-le-Vieux, France; Tom Cushman of Allerton Cushman & Co., Sun Valley, Idaho; Marc Jobin and Steve Jaquith of MJ3 Inc., New York; Herb Obodda of H. Obodda, Short Hills, New Jersey; Stuart Wilensky of Stuart and Donna Wilensky Fine Minerals, Wurtsboro, New York; Irv Brown of Irv Brown Fine Minerals, Fallbrook, California; Edward Boehm of Joeb Enterprises, Solana Beach, California; K & K International, Falls Church, Virginia; William Pinch of Pittsford, New York; Rob Lavinsky of The Arkenstone, San Diego; Brian Cook of Nature's Geometry, Graton, California; G.E.0. International Co. Ltd of Bangkok; and Papas Gem Co. Ltd., Bangkok. We thank John I. Koivula of GIA, Carlsbad, for supplying samples and photomicrographs. Dr. Petr Černý of the University of Manitoba, Winnipeg, provided useful comments on the manuscript. Assistance with document scanning and computer-automated translations was provided by Denise Breceda of the GIA Gem Laboratory, Stuart Overlin of Gems & Gemology, and Sheryl Ben of the Richard T. Liddicoat Library and Information Center in Carlsbad. Neil Barron and Ruth Patchick of the Liddicoat library obtained numerous publications via interlibrary loan. Portions of Zagorsky et at. (1999) were translated by Inna Saphonova, Novosibirsk, Russia.

Additional details

Created:
August 22, 2023
Modified:
October 24, 2023