Linnaeite: Properties and Occurrences

Linnaeite is a cobalt sulfide mineral with the composition Co2+Co3+2S4. It was discovered in 1845 in Västmanland, Sweden, and was named to honor Carl Linnaeus (1707–1778). It is a mineral of pale steel-gray color and metallic luster that occurs in isometric crystals and also massive and that is essentially a cobalt sulfide. It is a sulphide of cobalt-containing some nickel or copper.

Linnaeite forms a series with polydymite, Ni+2Ni+32S4. Linnaeite is found in hydrothermal veins with other cobalt and nickel sulfides in many localities around the world.

General Information

  • Category: Sulfide mineral, Thiospinel group, Spinel structural group
  • Formula: Co2+Co3+2S4
  • Crystal system: Cubic
  • Crystal class: Hexoctahedral (m3m)
  • Color: Steel gray to gray violet.

Properties

Linnaeite is commonly formed with other cobalt sulfides but usually as just a trace. It is a mineral of pale steel-gray color and metallic luster, occurring in isometric crystals, and also massive. It is not a well-known mineral but is still an important ore of the strategically valuable metal cobalt. It is found with cobalt and nickel sulfides in hydrothermal veins.

  • Crystal habit: As octahedral crystals; massive, granular
  • Twinning: On {111}
  • Cleavage: Imperfect on {001}
  • Fracture: Subconchoidal
  • Mohs scale hardness: 4.5-5.5
  • Luster: Metallic
  • Streak: Grayish-black
  • Diaphaneity: Opaque
  • Specific gravity: 4.8-5.8

Occurrence: In hydrothermal veins with other cobalt and nickel sulfides.

A typical occurrence is the Siegen district, Germany. The members of this series crystallize in the isometric system; they all have spine-like structures. In a few areas, it has formed in large quantities and has become a valuable ore in mines in Zaire and Zambia.

Association: Chalcopyrite, pyrrhotite, millerite, bismuthinite, gersdorffite, carrollite, cattierite, ullmannite, marcasite, pyrite, galena, sphalerite.

 

Information Source: