Andradite

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Description

A type of garnet composed of a calcium iron silicate. The color of andradite may be yellow, red, green, brown or black. Bright green andradite, or demantoid, is also called the emerald of the Urals. Gemstone quality andradite is mined in the Ural Mountains, Italy, Switzerland, Norway, France, and in the United States (Arkansas and New Jersey).

Synonyms and Related Terms

garnet; demantoid (green, emerald of the Urals); topazolite (yellow); melanite (brown or black); andradita (Esp.); andradite (Port.); Andradit (Deut.); andradiet (Ned.)

Raman

Andraditeitaly1.jpg


Other Properties

Fracture = conchoidal Luster = vitreous to resinous. Streak = colorless. Birefringence = none. Dispersion = 0.057 Pleochroism = none. UV fluorescence = inert

Composition Ca3Fe2Si3O12
Mohs Hardness 6.5 - 7.0
Density 3.9
Refractive Index 1.887

Additional Information

Mineralogy Database: Andradite

Comparisons

Properties of Gemstones


Sources Checked for Data in Record

  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979

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