Multi-analytical characterization of minerals of the bowieite-kashinite series from Niznhy-Tagil complex, Urals (Russia) and comparison with worldwide occurrences.

Grains of the bowieite–kashinite solid-solution series were characterized by electron microprobe analysis, single-crystal Xray diffraction, and Raman spectroscopy. The grains were recovered from dunitic rocks located in the Svetly Bor Ural-Alaskan type massif, Urals, Russia. Bowieite and kashinite occur as small inclusions (up to 100 lm in size) in isoferroplatinum grains up to 1 mm in diameter. Single-crystal X-ray diffraction data for two selected grains, with compositions (Rh1.16Ir0.82Cu0.02)P2.00S3.00 and (Ir1.06Rh0.87Cu0.04)P1.97S3.03, confirm that the minerals are orthorhombic with similar cell dimensions: a 8.46(1), b 6.00(1), c 6.14(1) ˚A for bowieite, and a 8.46(1), b 5.99(1), c 6.14(1) ˚A for kashinite. The Raman spectra of the same two single grains show similar characteristic bands. One grain with composition (Ir0.26Rh0.13Pt0.12Ni0.18 Cu0.18Fe0.11)P0.98S was found associated with the kashinite. It shows a distinctive Raman spectrum and may represent a new platinum-group mineral, although the small size (less than 20 lm) prevented us from obtaining X-ray diffraction data. Our data for the bowieite–kashinite series are compared with selected worldwide occurrences