Muscovite is a mineral from the micas group. The name comes from the word "Muscovy", because. Since ancient times, it has been used in Russia in windows instead of glass that was not yet used and was supplied by merchants abroad. It has very high electrical insulating properties. It is divided into several varieties.
You can see Muscovite stone for sale and buy it in the Minerals of Russia online store.
General | |
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Category | Phyllosilicate |
Formula (repeating unit) |
KAl2(AlSi3O10)(F,OH)2 |
IMA symbol | Ms |
Strunz classification | 9.EC.15 |
Dana classification | 71.02.02a.01 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | C2/c |
Unit cell | a = 5.199 Å, b = 9.027 Å, c = 20.106 Å, β = 95.78°; Z = 4 |
Identification | |
Color | White, grey, silvery |
Crystal habit | Massive to platy |
Twinning | Common on the [310], less common on the {001} |
Cleavage | Perfect on the {001} |
Fracture | Micaceous |
Tenacity | Elastic |
Mohs scale hardness | 2–2.5 parallel to {001} 4 right angle to {001} |
Luster | Vitreous, silky, pearly |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 2.76–3 |
Optical properties | Biaxial (-) |
Refractive index | nα = 1.552–1.576 nβ = 1.582–1.615 nγ = 1.587–1.618 |
Birefringence | δ = 0.035 – 0.042 |
Pleochroism | Weak when colored |
Dispersion | r > v weak |
Ultraviolet fluorescence | None |