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A sakhaite-like mineral from the Kombat Mine in Namibia

Published online by Cambridge University Press:  05 July 2018

Pete J. Dunn
Affiliation:
Department of Mineral Sciences, Smithsonian Institution, Washington, DC 20560, USA
Donald R. Peacor
Affiliation:
Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
Joseph A. Nelen
Affiliation:
Department of Mineral Sciences, Smithsonian Institution, Washington, DC 20560, USA
Robert A. Ramik
Affiliation:
Department of Mineralogy, Royal Ontario Museum, Toronto, Ontario, Canada M5S 2C6
John Innes
Affiliation:
CSIRO Institute of Minerals, Energy, and Construction Division of Exploration Geoscience, Private Bag P.O., Wembley, W.A. 6014, Australia

Abstract

Sakhaite from the Kombat Mine in Namibia is cubic, with a = 14.749(1)Å; the space group is a subgroup of Fd3m, the density is 2.88 g/cm3, and the index of refraction is n = 1.642(2). It is apparently more highly hydrated than previously described sakhaite, and has more aluminosilicate substitution. The idealized composition is Ca24Mg8(BO3)8[(BO3)y{AlSi4(O,OH)<16}x](CO3)8.< 8H2O with x = 0.73 and y = 5.0.

Type
Silicate Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1990

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References

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