Cubanite

Formula:  CuFe₂S₃

Origin of name:  Locality; Cuba

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:  Common on {110}, pairs, fourlings, or sixlings

Unit cell: a = 6.46 Å, b = 11.12 Å, c = 6.233 Å

Colour:  Bronze to brass-yellow

Diaphaneity: Opaque

Luster:  Metallic

Habit:  Crystals thick tabular, elongated, striated; massive

Hardness:  3.5

Specific gravity:  4.03 to 4.18

Cleavage:  2; {110}  and {1-30} parting

Tenacity:  Conchoidal

Streak:

Synonyms/varieties:

Comments:  Dimorphous with isocubanite; magnetic. Found in hydrothermal deposits formed at relative high temperatures in pyrrhotite-pentlandite ores in which it commonly occurs as intimate oriented intergrowths with chalcopyrite.