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Malanite—A New Cupric Platinum (Pt 3+ ) and Iridium (Ir 3+ ) Sulphide
Author(s) -
Zuxiang Yu
Publication year - 1997
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.1997.tb00355.x
Subject(s) - pleochroism , pentlandite , platinum , iridium , chromite , pyrrhotite , electron microprobe , crystallography , chemistry , rhodium , nickel , delafossite , osmium , analytical chemistry (journal) , mineralogy , materials science , metallurgy , crystal structure , pyrite , oxide , ruthenium , catalysis , biochemistry , chromatography
Malanite was first found in veinlets of disseminated copper–nickel ores in Zunhua County, Hebei Province, and then in platinum–bearing chromite ores in Shuangfeng Village, Yanshan. In the former case, malanite appears as octahedrons or dodecahedrons associated with pyrrhotite, pentlandite, sperrylite and cooperite; while in the latter case, it is massive or present in anhedral glomerocrysts, filling in cracks of iridisite and associated with osmiride, ferrian platinum and iridisite. Malanite is steel–grey in colour, opaque with metallic lustre and black streaks and brittle with no magnetism. H M = 5.0, VHN 20 = 417kg/mm 2 , cleavage {111} sometimes observed. The calculated density is 7.57 g/cm 3 . The reflective colour is white with a light green tint. Internal reflections are not observed. This mineral is isotropic, showing no birefiection or reflection pleochroism in air. By means of electron microprobe analysis, the empirical formula (based on 7 atoms) is expressed as (Cu 0.93 Fe 0.06 ) Σ0.99 (Pt 1.03 Ir 0.66 Rh 0.04 pd 0.03 Co 0.20 Ni 0.03 ) 1.99 S 4.03 ) or (Cu 0.95 Fe 0.07 ) Σ1.02 (Pt 1.37 Ir 0.45 Co 0.11 Rh 0.08 )Σ 2.01 S 3.97 . Five strongest lines ( hkl, d, I ) of X–ray powder diffraction data of malanite are 311,2.98 (6);400,2.48(5); 333,1.90(7); 440, 1.75 (10); 731, 1.29 (5). It was known on the basis of X–ray powder diffraction data that malanite is cubic, and the space group is Fd3m with a = 0.9940nm, V = 0.9821 (3) nm 3 and Z = 4. The type material of malanite is deposited at the Geological Museum of China (GMC)