Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-25T06:04:45.109Z Has data issue: false hasContentIssue false

Damaraite, a new lead oxychloride mineral from the Kombat mine, Namibia (South West Africa)

Published online by Cambridge University Press:  05 July 2018

A. J. Criddle
Affiliation:
Department of Mineralogy, The Natural History Museum, Cromwell Rd., London SW7 5BD, U.K.
P. Keller
Affiliation:
Institut für Mineralogie und Kristallchemie, Universität Stuttgart, D-700 Stuttgart, Germany
C. J. Stanley
Affiliation:
Department of Mineralogy, The Natural History Museum, Cromwell Rd., London SW7 5BD, U.K.
J. Innes
Affiliation:
CSIRO Division of Exploration Geoscience, Private Bag, Wembley, Western Australia 6014

Abstract

Damaraite, ideally 3PbO.PbCl2, is a new mineral which occurs with jacobsite, hausmannite, hematophanite, native copper, an unnamed Pb-Mo oxychloride, calcite, and baryte, in specimens from the Asis West section of the Kombat mine, Namibia (South West Africa). Damaraite is colourless and transparent with a white streak, and adamantine lustre. It is brittle with an irregular to subconchoidal fracture and a cleavage on (010). The mineral has a low reflectance, a weak bireflectance, barely discernible reflectance pleochroism, from grey to slightly bluish grey in some sections, and is weakly anisotropic. Reflectance data in air and in oil are tabulated. Colour values relative to the CIE illuminant C for the most strongly bireflectant grain are, for R1 and R2 respectively:

It has a VHN50 of 148 (range 145–154) with a calculated Mohs hardness of 3. X-ray powder diffraction studies give the following parameters refined from the powder data: orthorhombic; space group Pma2, Pmam or P21am; a 15.104(1), b 6.891(1), c 5.806 (1)Å; V is 604.3 (4)Å3 and Z = 3. Dcalc 7.84 g/cm3. The strongest six lines of the powder pattern are [d in Å (I) (hkl)]: 2.902 (10) (121,002); 2.766 (10) (510,221); 2.877 (9) (411); 3.164 (6) (401); 3.135 (6) (220); 1.747 (b) (313,721,531). The name is for the Damara sequence which hosts the Kombat deposit.

Type
Mineralogy and Petrology
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

Aurivillius, B. (1982) On the crystal structure of a number of non-stoichiometric mixed lead oxide halides composed of PbO-like blocks and single halogen layers. Chemica Scripta 19, 9-107.Google Scholar
Aurivillius, B. (1983) On the crystal structure of some non-stoichiometric mixed lead oxide halides and their relation to the minerals Iorettoite and sundiusite. Ibid. 22, 5-11.Google Scholar
Criddle, A. J., Stanley, C. J., Chisholm, J. E. and Fejer E. E. (1983) Henryite, a new copper-silver telluride from Bisbee, Arizona. Bull. Mineral. 106, 511-17.Google Scholar
Dunn, P. J., Peacor, D. R., Su, S.-C., Nelen, J., and von Knorring, O. (1986) Johninnesite, a new sodium manganese arsenosilicate from the Kombat Mine, Namibia. Mineral. Mag. 50, 667-70.CrossRefGoogle Scholar
Gabrielson, O., Partwel, A., and Wickman, F. E., (1958) Blixite, a new lead oxyhalide mineral from Langban. Arkiv Mineral. Geol. 2, 411-15.Google Scholar
Gmelins Handbuch (1969) Blei, Teil C, Lieferung 1, 335. Verlag Chemie, Weinheim.Google Scholar
Innes, J. and Chaplin, R. C. (1986) Ore bodies of the Kombat Mine, South West Africa/Namibia, pp. i789-1805. In Mineral Deposits of southern Africa. (Anhaeusser, C. R. and Maske, S., eds.) Vol.2, pp. 10212335. Geol. Soc. South Africa.Google Scholar
Peacor, D. R., Dunn, P. J., Su, S.-C. and Innes, J. (1987) Ribbeite, a polymorph of alleghanyite and member of the leucophoenicite group from the Kombat mine, Namibia. Am. Mineral. 72, 213-6.Google Scholar
Peacor, D. R., Essene, E. J., Rouse, R. C., Dunn, P. J., Nelen, J. A., Grice, J. D., Innes, J., and yon Knorring, O. (1988) Holdawayite, a new manganese bydroxylcarbonate from the Kombat mine, Namibia. Ibid. 73, 632-6.Google Scholar
Perrault, G., Vincent, H. and Renaud, M. (1971) Étude cristallographique de deux oxychlorures de plomb synthetiques Pb3O2Cl2 et Pb2OCl2 . Bull. Soc. fr. Mineral. Crist. 94, 108-12.Google Scholar
Rouse, R. C., Dunn, P. J., and Innes, J. (1986) Kombarite, the vanadium analogue of sahlinite, from the Kombat Mine, South West Africa. Neues Jahrb. Mineral., Mh., 519-22.Google Scholar
Rouse, R. C., Peacor, D. R., Dunn, P. J., Criddle, A. J., Stanley, C. J. and Innes, J. (1988) Asisite, a silicon-bearing lead oxychloride from the Kombat mine, South West Africa (Namibia). Am. Mineral. 73, 643-50.Google Scholar
Wells, A. F. (1984) Structural inorganic chemistry. Clarendon Press, Oxford.Google Scholar