Determination of Minerals in Platinum Concentrates from the Transvaal by X-Ray Methods

F. A. Bannister and M. H. Hey
Assistant-Keepers in the Mineral Department of the British Museum of Natural History.

Summary: X-ray rotation photographs have been used to distinguish and select for chemical analysis the various platinum- and palladium-bearing minerals present in concentrates of Bushveld platinum ore. The name cooperite is retained for PtS, tetragonal spacegroup D4h9. The face-centred unit cell with edges a = 4·91, c = 6·10 Å., contains 4PtS. The structure is a simple type of fourfold co-ordination built up from planar PtS4 groups and tetrahedral Spt4 groups, the Pt-S distance being 2·32 Å. Laurite (RuS2) occurs as small pyritohedral-cubic crystals and has the pyrite structure with unit-cell edge a = 5·59 Å, and parameter u between 0·39 and 0·395. The third mineral (Pt,Pd,Ni)S containing about 20 % Pd and 5 % Ni, is also tetragonal with unit-cell edges a = 6·37, c = 6·58 Å. The unit cell contains 8(Pt,Pd,Ni)S, and the space-group is D4h2. The name braggite is proposed for this mineral as being the first new mineral to be discovered by X-ray methods.

Mineralogical Magazine; September 1932 v. 23; no. 138; p. 188-206; DOI: 10.1180/minmag.1932.023.138.05
© 1932, The Mineralogical Society
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