Colusite

Formula:  Cu₂₆V₂(As,Sn,Sb)₆S₃₂

Origin of name:  From locality; near Colusa claim, Butte, Montana

Crystal system:  Cubic

Crystal class:  -43m

Twinning: Rare on {111}

Unit cell: a = 10.538 Å

Colour:  Bronze

Diaphaneity:  Opaque

Luster:  Metallic

Habit:  Crystals tetrahedral; usually massive

Hardness:  3 to 4

Specific gravity:  4.50

Cleavage:  None

Tenacity: Brittle

Streak:  Black

Synonyms/varieties:

Comments: Found in hydrothermal copper ore veins with other sulphides