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CategoryOxide mineral
Chemical formulaMgO
ColorColorless, grayish white, yellow, brownish yellow, green, black
Crystal habitGranular, generally occurs as anhedral to subhedral crystals in matrix
Crystal systemIsometric - Hexoctahedral
Cleavage{001} perfect; {111} imperfect, may exhibit parting on {011}
FractureBrittle to conchoidal
Mohs Scale hardness6
Optical PropertiesIsotropic
Specific gravity3.67 - 3.9
DiaphaneityTransparent to translucent
Other CharacteristicsFluorescent, Long UV=light yellow.

Periclase occurs naturally in contact metamorphic rocks and is a major component of most basic refractory bricks. It is a cubic form of magnesium oxide (MgO).

The old term for the mineral is magnesia. Stones from the Magnesia region in ancient Anatolia contained both magnesium oxide and hydrated magnesium carbonate as well as iron oxides (such as magnetite). Thus these stones, called Stones from Magnesia in antiquity, with their unusual magnetic properties were the reason the terms magnet and magnetism were coined. Periclase is usually found in marble and pure periclase is colorless.


  1. ^ Handbook of Mineralogy
  2. ^ Webmineral data
  3. ^ Mindat
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Periclase". A list of authors is available in Wikipedia.
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