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Iowaite, a re-investigation

Published online by Cambridge University Press:  05 July 2018

R. S. W. Braithwaite
Affiliation:
Chemistry Department, University of Manchester Institute of Science and Technology, Manchester M60 1QD, U.K.
P. J. Dunn
Affiliation:
Department of Mineral Sciences, Smithsonian Institution, Washington, D.C., 20560, U.S.A.
R. G. Pritchard
Affiliation:
Chemistry Department, University of Manchester Institute of Science and Technology, Manchester M60 1QD, U.K.
W. H. Paar
Affiliation:
Institüt für Mineralogie der Universitat Salzburg, Hellbrunnerstrasse 34/III, A-5020 Salzburg, Austria

Abstract

Iowaite has been re-examined using new, well crystallized material from the Palabora open pit mine, Transvaal. Microprobe, carbon analyser and thermal analyses, powder and single-crystal X-ray diffraction, infrared, UV-visible and mass spectroscopic and optical studies were made. The ideal formula is (OH)16Cl2·4H2O. It is trigonal, Rm, a = 3.1183(9), c = 24.113(8) Å, V = 203.1(2) Å3, Z = 3/8; Dobs 2.09 g/cm3.; Dcalc 2.04 g/cm3; hardness (Mohs)=2 1/2. The interlayer Cl ions are displaced from the threefold axis. It is uniaxial negative, with ω = 1.561 ± 0.002, ε = 1.543 ± 0.002; coloured crystals are intensely pleochroic, due to intervalence charge transfer between the Fe3+ and Fe2+ substituting for Mg2+, with O pale yellow, E deep blue-green.

Type
Crystal Structure
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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References

Allmann, R. (1968) Ada Crystallogr., B24, 972–7.CrossRefGoogle Scholar
Allmann, R. and Donnay, J. D. H. (1969) Amer. Mineral., 54, 296–9.Google Scholar
Bish, D. L. (1980) Bull. Mineral. 103, 170–5. [Mineral. Abs. 84M/2698].Google Scholar
Drits, V. A., Sokolova, T. N., Sokolova, G. V., and Cherkashin, V. I. (1987) Clays Clay Minerals, 35, 401–17.CrossRefGoogle Scholar
Fleischer, M. and Mandarino, J. A. (1991) Glossary of Mineral Species, The Mineralogical Record Inc., Tucson, Arizona.Google Scholar
Forster, I. F. (1958) Trans. Geol. Soc. S. Africa, 61, 359–65.Google Scholar
Hanekom, H. J., Van Stade, C. M. H., Smit, P. J., and Pike, D. R. (1965) Mem. Geol. Survey R. S. Africa, 54.Google Scholar
Heinrich, E. W. (1970) Canad. Mineral., 10, 585–98.Google Scholar
Ingram, L. and Taylor, H. F. W. (1967) Mineral. Mag., 36, 465–79.Google Scholar
Kashaev, A. A., Feoktisov, G. D., and Petrova, S. V. (1982) Zap. Vses. Mineral. Obshch., Ill, 121-7 [Mineral. Abs. 83M/1943].Google Scholar
Kohls, D. W. and Rodda, J. L. (1967) Amer. Mineral. 52, 1261–71.Google Scholar
Lombaard, A. F., Ward-Able, N. M., and Bruce, R. W. (1964) in Haughton, S. H. (Ed. The Geology of some Ore Deposits of Southern Africa, 2, 315–37. Geol. Soc. S. Africa, Johannesburg.Google Scholar
Mumpton, F. A., Jaffe, H. W., and Thompson, C. S. (1965) Amer. Mineral., 50, 1893–913.Google Scholar
Palabora Mining Co. Ltd. Mine geological and mineralogical staft (1976) Econ. Geol., 71, 177–92.CrossRefGoogle Scholar
Russell, H. D., Hiemstra, S. A., and Groeneveld, D. (1955) Trans. Geol. Soc. S. Africa, 58, 197–208.Google Scholar
Taylor, H. F. W. (1969) Mineral. Mag., 37, 338-2.Google Scholar
Taylor, H. F. W. (1973. Mineral Mag., 39, 377–89.CrossRefGoogle Scholar