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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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