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A green, calcium magnesium silicate mineral sometimes used as a Gemstone. Diopside is a Pyroxene type mineral with short, monoclinic crystals. The transparent to translucent crystals have either a square or octagonal cross section. The color of diopside crystals ranges from light to dark green. Diopside has been found at many locations throughout Europe (Russia, Finland, Sweden, Switzerland and Italy), Canada (Ontario, Quebec) and the United States (New York, California and Maine). Powdered diopside is used as a matting agent in ceramic glazes.

Synonyms and Related Terms

calcium magnesium silicate; diopside (Fr.); diópsido (Esp., Port.); Diposid (Deut.); diopsiet (Ned.)





Physical and Chemical Properties

  • Monoclinic system with slender square or octagonal prisms that are often twinned.
  • Cleavage occurs at intersecting angles of 87 and 93 degrees although fracture is usually uneven.
  • Luster = vitreous to dull.
  • Streak = white, gray or green
Composition CaMgSi2O6
Mohs Hardness 5.0 - 6.5
Density 3.2-3.6 g/ml
Refractive Index 1.66-1.76

Resources and Citations

  • Robert Fournier, Illustrated Dictionary of Practical Pottery, Chilton Book Company, Radnor, PA, 1992
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998