Mineral description : Chalcocite

Mineral class Sulphides : Chalcocite group
Chemical formula Cu2S
Crystal system Monoclinic (pseudo-orthorombic).
Habitus Flat pseudohexagonal crystals. Usually massive grainy aggregates.
Cleavage Imperfect in two prismatic directions.
Hardness 2.5 - 3
Density 5.5 - 5.8
Color Grayish black, opaque.
Streak Shiny black to dark gray.
Luster Metallic.
Description Chalcosite is an important copper ore.
Occurance Forms in hydrothermal veins and below the oxidation zone of copper deposits. Also found in sedimentary rocks.
Associates  
Notes Often found with a dull tarnish.
Easily soluble in nitric acid.
Green color in a flame.
Localities Found only in a few of the copper ores in Sweden
  • Grindsbol, Dalsland. In quartz veins.
  • Glava, Dalsland. In quartz veins.
  • Sjangeli, Lappland.
  • Nautanen, Lappland.
  • Fridhem, Lappland.
  • Solstads copper mine, Småland.
  • Norberg, Västmanland.
  • Fröå, Jämtland.

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Last changed : 2001-02-07