Cubanite: Properties and Occurrences

Cubanite is a yellow mineral of copper, iron, and sulfur, CuFe2S3. It is an orthorhombic-dipyramidal mineral containing copper, iron, and sulfur. It is a rare copper mineral that does not contribute much to the supply of copper. It is also associated with gold in some gold mines. It is far more desired as a mineral specimen.

Cubanite was first described in 1843 for an occurrence in the Mayarí-Baracoa Belt, Oriente Province, Cuba.

General Information

  • Category: Sulfide mineral
  • Formula: CuFe2S3
  • Crystal system: Orthorhombic
  • Crystal class: Dipyramidal (mmm)

Properties

Cubanite has a bright metallic luster and a brassy golden color that is really striking. It commonly forms twins that are seen as either sharply pointed chevrons or as cyclic twins of six-rayed “stars” or “flowers”. Cubanite is named after Cuba, the country of its type locality.

  • Color: Bronze to brass-yellow
  • Crystal habit: Crystals elongated to thick tabular, striated also massive
  • Cleavage: Parting on {110} and {130}
  • Fracture: Conchoidal
  • Mohs scale hardness: 3.5-4
  • Luster: Metallic
  • Streak: Black
  • Diaphaneity: Opaque
  • Specific gravity: 4.0-4.2

Occurrence

Cubanite occurs in high-temperature hydrothermal deposits with pyrrhotite and pentlandite as intergrowths with chalcopyrite. It results from exsolution from chalcopyrite at temperatures below 200 to 210 °C. It has also been reported from carbonaceous chondrite meteorites. A rare constituent of some carbonaceous chondrite meteorites.

 

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