Breithauptite

Formula: NiSb Antimonide, nickeline group
Specific gravity: 7.591 to 8.23
Hardness: 5½
Streak: Reddish brown
Colour: Copper-red with a violet tint
Environments:

Hydrothermal environments

Breithauptite occurs in hydrothermal calcite veins associated with cobalt-nickel-silver ores, associated with silver, nickeline, maucherite, cobaltite, ullmannite, tetrahedrite, pyrrhotite, cubanite, chalcopyrite, sphalerite, galena and calcite.

Common impurities: Fe,Co,As,S