OWENSITE, (Ba,Pb)6(Cu,Fe,Ni)25S27, A NEW MINERAL SPECIES FROM THE WELLGREEN Cu-Ni-Pt-Pd DEPOSIT, YUKON*

J.H. GILLES LAFLAMME
Canada Centre for Mineral and Energy Technology, 555 Booth Street, Ottawa, Ontario K1A 0G1

ANDREW C. ROBERTS
Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8

ALAN J. CRIDDLE
The Natural History Museum, Cromwell Road, London SW7 5BD, U.K.

LOUIS J. CABRI
Canada Centre for Mineral and Energy Technology, 555 Booth Street, Ottawa, Ontario K1A 0G1

* Geological Survey of Canada contribution number 28194.

Abstract

Owensite is a new mineral species found in samples from the Wellgreen Cu-Ni-Pt-Pd deposit, Kluane District, Yukon Territory. The mineral, which is very rare, occurs as small anhedral grains ranging from 6 × 12 to 43 × 110 µm, and is closely associated with pyrrhotite, magnetite, chalcopyrite and pentlandite. Owensite is opaque, with a metallic luster and a black streak. The mineral is pale brownish grey in plane-polarized reflected light, and isotropic. Reflectance spectra and color values are given. Owensite displays cubic symmetry and has a refined unit-cell parameter a of 10.373(2) Å and a V of 1116.0(3) Å3, with the following strongest X-ray powder lines [d in Å(I)(hkl)]: 3.460(40)(300), 3.281(40)(310), 2.996(90)(222), 2.378(90)(331), 1.835(100)(440) and 1.779(40)(433). Its crystal structure has been determined as cubic, space group Pm3m (Szyma ski 1995). Based on the least-squares- refined unit-cell parameter, a = 10.349(1) Å, with Z = 1, Dcalc is 4.78 g/cm3. The average result of electron-microprobe 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 (Ba5.42Pb0.56) =5.98(Cu12.87Fe11.70Ni0.14) =24.71S27.31, or simply (Ba,Pb)6(Cu,Fe,Ni)25S27. Structurally, owensite is closely related to djerfisherite K6Na(Fe,Ni,Cu)24S26Cl, but it is totally devoid of the Cl and monovalent metals found in the latter mineral. Owensite honors DeAlton R. Owens (1934- ) of the Canada Centre for Mineral and Energy Technology, Ottawa, for his contributions to mineralogy, particularly in the field of electron-microbeam analyses.

Keywords: new mineral species, owensite, (Ba,Pb)6(Cu,Fe,Ni)25S27, X- ray diffraction data, electron-microprobe data, reflectance data, Wellgreen deposit, Yukon Territory.