Cuprospinel: Properties and Occurrences

Cuprospinel is an inverse spinel with the formula CuFe2O4, where copper substitutes some of the iron cations in the structure. It is an isometric-hexoctahedral black mineral containing aluminum, copper, iron, magnesium, and oxygen. Its structure is similar to that of magnetite, Fe3O4, yet with slightly different chemical and physical properties due to the presence of copper.

The mineral was first characterized by Ernest Henry Nickel, a mineralogist with the Department of Energy, Mines, and Resources in Australia, in 1973.

General Information

  • Category: Oxide mineral (Spinel group)
  • Formula: CuFe2O4 or (Cu, Mg)Fe2O4
  • Crystal system: Isometric
  • Crystal class: Hexoctahedral (m3m)
  • Space group: Cubic

Properties

  • Formula mass: 239.23 g/mol
  • Color: Black, gray in reflected light
  • Crystal habit: Irregular grains, laminae intergrown with hematite
  • Mohs scale hardness: 6.5
  • Luster: Metallic
  • Streak: Black
  • Diaphaneity: Opaque
  • Specific gravity: 5 – 5.2

It adopts both cubic and tetragonal phases at room temperature, yet as the temperature is elevated the cubic form is most stable.

Occurrence: In highly oxidized material, once spontaneously ignited, in an ore dump.

Cuprospinel is a mineral that occurs naturally in Baie Verte, Newfoundland, Canada. The mineral was found in an exposed ore dump, on the property of Consolidated Rambler Mines Limited near Baie Verte, Newfoundland.

Association: Pyrite, chalcopyrite, sphalerite, pyrrhotite, hematite.

 

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