Rhodarsenide (Rh,Pd) (sub 2) As, a new mineral

Rhodarsenide has been found in concentrates from placers of the Srebrnica River, near Veluce, central Serbia; it is associated with PGE alloys, Rh-Ir sulpharsenides and sperrylite and occurs as inclusions (up to 80 X 100 mu m) in Pt-Fe and Ru-Os-Ir alloys. In reflected light it is brownish; pleochroism and anisotropy weak to distinct; at 589 nm reflectance values are 49.5-48.2 in air and 40.4-36.4 in oil; VHN 493-585 kg/mm (super 2) . EPMA results on individual grains gave Rh 38.53-60.81, Pd 12.10-34.67, Pt 0.00-2.38, Ir 0.09-0.48, Fe 0.00-0.10, Cu 0.08-0.46, As 23.42-27.96, Sb 0.09-1.60, Te 0.08-1.20, corresponding with (Rh (sub 1.67) Pd (sub 0.34) )As (sub 0.99) and (Rh (sub 1.07) Pd (sub 0.94) Pt (sub 0.03) )(As (sub 0.91) Sb (sub 0.04) Te (sub 0.01) ). Indexed XRD powder data are tabulated; strongest lines 2.237(10), 2.067(8), 2.426(7), 1.935(6), 1.860(5) Aa; a 5.866, b 3.893, c 7.302 Aa, V 166.7 Aa (super 3) ; Z = 4; D (sub calc) 11.32 g/cm (super 3) .