Tellurobismuthite
Tellurobismuthite is a telluride mineral: bismuth telluride. It crystallizes in the trigonal system. There are natural cleavage planes in the direction as the crystal is effectively lamellar in that plane. The Mohs hardness is 1.5 - 2 and the specific gravity is 7.815. It is a dull grey color, which exhibits a splendent luster on fresh cleavage planes.It was first described in 1815 and type localities include the Mosnap mine in Toke, Telemark, Norway; the Little Mildred mine, Sylvanite District, Hidalgo County, New Mexico and the Boly Field Mine, Dahlonega, Lumpkin County, Georgia.
It occurs in low sulfur hydrothermal gold-quartz veins and occurs with native gold, native bismuth, gold tellurides, tetradymite, altaite, chalcopyrite and pyrrhotite.