Aurostibite

Formula:  AuSb₂

Origin of name:  From composition (Latin aurum = gold and stibium = antimony)

Crystal system:  Cubic

Crystal class:  2/m -3

Twinning:

Unit cell: a = 6.646 Å

Colour:  Lead-grey with a slight pinkish tinge

Diaphaneity: Opaque

Luster:  Metallic

Habit:  Microscopic rounded, elongated anhedral grains

Hardness:  3

Specific gravity:  9.98 (synthetic)

Cleavage:  None

Tenacity:

Streak: Bronze

Synonyms/varieties:

Comments:  Seen only in polished section, colour is for reflected light. Found in hydrothermal gold-quartz veins, in portions deficient in sulphur and containing other antimony minerals