Breithauptite

Breithauptite
Breithauptite on calcite from the Samson Mine, St Andreasberg, Harz Mountains, Lower Saxony, Germany (Field of view 17 mm)
General
Category	Antimonide mineral
Formula (repeating unit)	nickel antimonide (NiSb)
Strunz classification	2.CC.05
Crystal system	Hexagonal
Crystal class	Dihexagonal dipyramidal (6/mmm) H-M symbol: (6/m 2/m 2/m)
Space group	P63/mmc
Unit cell	a = 3.946 Å, c = 5.148 Å, Z = 2
Identification
Color	Pale copper-red, may be with violet tint
Crystal habit	Crystals rare, thin tabular or needlelike, to 1 mm; arborescent, disseminated, massive
Twinning	Twin plane {1011}
Cleavage	None
Fracture	Subconchoidal to uneven
Tenacity	Brittle
Mohs scale hardness	5.5
Luster	Metallic
Streak	Reddish brown
Diaphaneity	Opaque
Specific gravity	7.591–8.23 measured; 8.629 calculated
Pleochroism	Very distinct
References

Breithauptite is a nickel antimonide mineral with the simple formula NiSb. Breithauptite is a metallic opaque copper-red mineral crystallizing in the hexagonal - dihexagonal dipyramidal crystal system. It is typically massive to reniform in habit, but is observed as tabular crystals. It has a Mohs hardness of 3.5 to 4 and a specific gravity of 8.23.

It occurs in hydrothermal calcite veins associated with cobalt–nickel–silver ores.

It was first described in 1840 from the Harz Mountains, Lower Saxony, Germany and in 1845 for occurrences in the Cobalt and Thunder Bay districts of Ontario, Canada. It was named to honor Saxon mineralogist Johann Friedrich August Breithaupt (1791–1873).