Cubanite

cubanite

chalcopyrite

pyrrhotite

pentlandite

Images

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

Hydrothermal environments
Meteorites rare

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).

Localities

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

At the Mponeng Mine, West Wits, Far West Rand, West Rand District Municipality, Gauteng, South Africa, small sprays of brassy cubanite, less than 1 cm, have been found together with chalcopyrite and quartz. In another cavity in the same mine, secondary minerals included quartz, pyrrhotite, sphalerite and cubanite. Slender golden acicular crystals of cubanite to 15 mm were found perched on pyrrhotite (R&M 96.4.322-323).

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