Mineral, CoAsS; sp. gr. 6.0–6.5; hardness 5–6; cubic; from white to dark grey or greyish-black, all with a reddish tinge; grey-black streak; metallic lustre; crystals octahedra, cubes, and pentagonal-dodecahedra, also occurs massive, and in irregular grains; cleavage perfect cubic; occurs mainly in hydrothermal veins and contact metamorphic zones, and is associated with chalcopyrite, sphalerite, chlorite, tourmaline, and apatite. It is one of the principal ore minerals for cobalt.
Subjects: Earth Sciences and Geography.