Muscovite can also refer to a native or inhabitant of Muscovy or Moscow principality in Russia.
Muscovite, also known as 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. Muscovite melts at approximately 1320°C, has a Mohs hardness of 2 - 2.25 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. Muscovite is anisotropic, and has quite a high birefringence. Its crystal
system is monoclinic.
This article is licensed under the GNU Free Documentation License.
It uses material from the Wikipedia the free encyclopedia that anyone can edit.