Hostname: page-component-848d4c4894-4rdrl Total loading time: 0 Render date: 2024-06-26T06:24:24.254Z Has data issue: false hasContentIssue false

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barbieri, M., Cozzupoli, D., Federico, M., Fornaseri, M., Merlino, S., Orlandi, P. and Tolomeo, L. (1977) Harkerite from the Alban Hills, Italy. Lithos, 10, 133-41.CrossRefGoogle Scholar
Chichagov, A. V., Simonov, M. A. and Belov, N V. (1974) The crystal structure of sakhaite, Ca3Mg (BO3)2(CO3)xH2O. Doklady Acad. Nauk SSSR, 218, 576-9.Google Scholar
Dunn, P. J., Rouse, R. C. and Innes, J. (1986) Kombatite, the vanadium analogue of sahlinite, from the Kombat Mine, Southwest Africa. Neues Jahrb. Mineral. Mh., 519-22.Google Scholar
Giuseppetti, G., Mazzi, F. and Tadini, C. (1977) The crystal structure of harkerite. Am. Mineral. 62, 263-72.Google Scholar
Mandarinoi, J. (1981) The Gladstone-Dale relationship: Part IV. The compatibility concept and its application. Can. Mineral. 19, 441-50.Google Scholar
Weger, S. J. Jr, Hossner, L. R. and Ferrara, L. W. (1969) Determination of boron in fertilizers by atomic absorption spectrophotometry. J. Agric. Food Chem. 17, 276-8.CrossRefGoogle Scholar