OWENSITE, (BA,PB)(6)(CU,FE,NI)(25)S-27, A NEW MINERAL SPECIES FROM THE WELLGREEN CU-NI-PT-PD DEPOSIT, YUKON

Owensite is a new mineral species found in samples from the Wellgreen Cu-Ni-Pt-Pd deposit, Kluane District, Yukon Territory. The mineral, wh ich is very rare, occurs as small anhedral grains ranging from 6 x 12 to 43 x 110 mu m, and is closely associated with pyrrhotite, magnetite , chalcopyrite and pentlandite. Owensite is opaque, with a metallic lu ster and a black streak. The mineral is pale brownish grey in plane-po larized reflected light, and isotropic. Reflectance spectra and color values are given. Owensite displays cubic symmetry and has a refined u nit-cell parameter a of 10.373(2) Angstrom and a V of 1116.0(3) Angstr om(3), with the following strongest X-ray powder lines [d in Angstrom( I)(hkl)]: 3.460(40)(300), 3.281(40)(310), 2.996(90)(222), 2.378(90)(33 1), 1.835(100)(440) and 1.779(40)(433). Its crystal structure has been determined as cubic, space group Pm3m (Szymanski 1995). Based on the least-squares-refined unit-cell parameter, a = 10.349(1) Angstrom, wit h Z = 1, D-calc is 4.78 g/cm(3). The average result of electron-microp robe analyses gave: Ba 23.04, Pb 3.58, Cu 25.33, Fe 20.24, Ni 0.25, S 27.11, total 99.55 wt.%, which yields the empirical formula a=5.98)(Cu 12.87Fe11.70Ni0.14)(Sigma=24.71)S-27.31, or simply (Ba,Pb)(6)(Cu,Fe,Ni )(25)S-27. Structurally, owensite is closely related to djerfisherite K6Na(Fe,Ni,Cu)(24)S26Cl, but it is totally devoid of the Cl and monova lent metals found in the latter mineral. Owensite honors DeAlton R. Ow ens (1934-) of the Canada Centre for Mineral and Energy Technology, Ot tawa, for his contributions to mineralogy, particularly in the field o f electron-microbeam analyses.