AskDefine | Define muscovite

Dictionary Definition

Muscovite adj : of or relating to the residents of Moscow; "Muscovite street dealers"


1 a colorless or pale brown mica with potassium
2 a resident of Moscow

User Contributed Dictionary

see Muscovite



In 1850 from Muscovy glass, from the province Muscovy in Russia. Named by James Dwight Dana.


  1. A pale brown mineral of the mica group, being a basic potassium aluminosilicate with the chemical formula KAl2(Si3Al)O10(OH,F)2; used as an electrical insulator etc.



Extensive Definition

Muscovite (also known as Common mica, Isinglass, or Potash mica) is a phyllosilicate mineral of aluminium and potassium with formula: KAl2(AlSi3O10)(F,OH)2. It has a highly perfect basal cleavage yielding remarkably thin laminae (sheets), which are often highly elastic. Sheets of muscovite 5 metres by 3 metres have been found in Nellore, India.
Muscovite melts at approximately 1320°C, has a Mohs hardness of 2 - 2.25 parallel to the [001] face, 4 perpendicular to the [001] and a specific gravity of 2.76 - 3. It can be colorless or tinted through grays, browns, greens, yellows, or (rarely) violet or red, and can be transparent or translucent. The green chromium rich variety is called fuchsite.
Muscovite is the most common mica, found in granites, pegmatites, gneisses and schists, and as a contact metamorphic rock or as a secondary mineral resulting from the alteration of topaz, feldspar, kyanite, etc. In pegmatites, it is often found in immense sheets that are commercially valuable. Muscovite is in demand for the manufacture of fireproofing and insulating materials and to some extent as a lubricant.
The name of muscovite comes from Muscovy-glass, a name formerly used for the mineral because of its use in Russia for windows. It is anisotropic, and has quite a high birefringence. Its crystal system is monoclinic.
muscovite in Catalan: Moscovita
muscovite in Czech: Muskovit
muscovite in German: Muskovit
muscovite in Esperanto: Muskovito
muscovite in Spanish: Moscovita
muscovite in French: Muscovite
muscovite in Galician: Moscovita
muscovite in Italian: Muscovite
muscovite in Hebrew: מוסקוביט
muscovite in Hungarian: Muszkovit
muscovite in Dutch: Muscoviet
muscovite in Japanese: 白雲母
muscovite in Low German: Muskovit
muscovite in Polish: Muskowit
muscovite in Portuguese: Moscovita
muscovite in Russian: Серицит
muscovite in Slovak: Muskovit
muscovite in Finnish: Muskoviitti
muscovite in Turkish: Muskovit
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