Cubanite

chalcopyrite

pentlandite

Formula: CuFe₂S₃ Sulphide
Specific gravity: 4.0 to 4.2
Hardness: 3½
Streak: Grey-black
Colour: Brass to bronze-yellow
Magnetic
Environments:

Hydrothermal environments

Cubanite is a secondary mineral that occurs in high temperature hydrothermal veins, in pyrrhotite – pentlandite ores in which it commonly occurs as intimate oriented intergrowths with chalcopyrite (Webmin, HOM). It is a rare constituent of some carbonaceous chondrite meteorites (HOM).
Associated minerals include chalcopyrite, pyrite, pyrrhotite, pentlandite and sphalerite (HOM, Mindat).

Cubanite is very sensitive to temperature, pressure and compositional variations. When heated between 200 and 210°C, cubanite transforms irreversibly to isocubanite (Mindat, HOM).

The type locality is Barracanao, Mayarí-Baracoa Belt, Holguín Province, Cuba.

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