Mineral Information and Data:

Cubanite
CuFe2S3 [CNMNC approved formula]

Named after its locality: Barracanao, Cuba.

IMA status : Valid species (Pre-IMA 1843) Grandfathered
CLASSIFICATION 
Dana
(8th edition) :
02.09.13.01  
  (02) Sulfides - Including Selenides and Tellurides
  (02.09) where Am Bn Xp, with (m+n):p=1:1
  (02.09.13)
  
Nickel-Strunz
(10th edition) :
02.CB.55a
  (02) Sulfides
  (02.C) Metal Sulfides, M:S = 1:1 (and similar)
  (02.CB) With Zn, Fe, Cu, Ag, etc.
  
Crystal system: Orthorhombic System
Point group (H-M): mmm (or 2/m 2/m 2/m) — dipyramidal
Unit cell: a = 6.467(1) Å, b = 11.117(1) Å, c = 6.231(2) Å
Crystal Habit: Crystals elongated || [001]; thick tabular {001} and {110}; {001} striated || [010], to 3 cm; also massive.
Twinning: Common with twin plane {110}, in pairs, also as fourlings and sixlings; then pseudohexagonal.
  
Color: Brass-yellow to bronze-yellow
Diaphaneity: Opaque
Hardness (Mohs): 3.5
Measured Density: 4.03 – 4.18 g/cm3
Cleavage: Parting on {110} and {130}
Fracture: Conchoidal
  
Polymorphism and Series: Dimorphous with isocubanite.
Geologic Setting: In hydrothermal deposits formed at relatively high temperature, in pyrrhotite–pentlandite ores in which it commonly occurs as intimate oriented intergrowths with chalcopyrite. Cubanite may exsolve from chalcopyrite below about 200 °C–210 °C. A rare constituent of some carbonaceous chondrite meteorites.
Mineral Association: Chalcopyrite, pyrite, pyrrhotite, pentlandite, sphalerite.
  
Other Properties: Ferromagnetic (strongly attracted to magnetic fields).

 

Cubanite
Cubanite twin on dolomite.
Origin: Morro Velho mine, Nova Lima, Minas Gerais, Brazil
Sample size: Microscopic image
Photo and Owner: Lou Perloff

 

Cubanite
Prismatic golden or brassy crystals of cubanite to 1mm with abundant pyrrhotite crystals to 4 mm. There are at least two crystals of cubanite, possibly more. Matrix is clear bladed rhombs of dolomite.
Origin: Morro Velho mine, Nova Lima, Minas Gerais, Brazil
Sample size: 10 x 5 x 6 cm
Photo: Tom Loomis

 

Cubanite
(zoom-in of above)

 

Cubanite
(zoom-in of above)

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