Breithauptite

Formula:  NiSb

Origin of name:  For Johann Friedrich August Briethaupt, German mineralogist (1791-1873)

Crystal system:  Hexagonal

Crystal class:  6/m 2/m 2/m

Twinning:  On {1-101}

Unit cell: a = 3.946 Ǻ, c = 5.148 Ǻ

Colour:  Copper red

Diaphaneity:

Luster:  Metallic

Habit:  Crystals thin tabular; massive; disseminated or arborescent

Hardness:  5.5

Specific gravity:  7.591 to 8.230

Cleavage:  None

Tenacity:  Subconchoidal to uneven; brittle

Streak:  Reddish brown

Synonyms/varieties:

Comments: found in hydrothermal calcite veins associated with Co-Ni-Ag ores