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A mineral composed of Cuprous sulfide. Chalcocite occurs in conjunction with other copper ores. It is a dark gray color with a bluish-green tarnish. Chalcocite is an important source for copper and is mined in Chile, Mexico, Nambia, England (Cornwall), Romania, the Ural Mountains and the U.S. (Montana, Arizona, Utah, Nevada, Alaska, Connecticut, New Mexico).


Synonyms and Related Terms

copper glance; cuprous sulfide; calcosita (Esp.); calcocite (Port.); Kupferglanz, Chalcocit (Deut.); chalcosiet (Ned.)

Physical and Chemical Properties

  • Orthorhombic crystal system.
  • Fracture = conchoidal; brittle.
  • Cleavage = poor in one direction.
  • Luster = metallic
  • Streak = gray to black
Composition Cu2S
Mohs Hardness 2.5 - 3.0
Density 5.5-5.8 g/ml

Resources and Citations

  • Henry Hodges, Artifacts: An Introduction to Early Materials and Technology, Ronald P. Frye, Kingston, Canada, 1988
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 232
  • Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976