Muscovite Mica

Muscovite is a common rock forming mineral found in igneous rocks such as granites and granitic pegmatites as well as metamorphic rocks such as schists. Like most micas, muscovite will form "books" of mica crystals from which perfect, thin sheets can be peeled. Some other micas are biotite, lepidolite, phologopite and vermiculite.

Chemical Formula:

KAl2(AlSi3O10)(OH)2

Mineral Class:

Phyllosilicate

Crystal System:

Monoclinic

Symmetry:

2/m

Hardness:

2-2.5

Specific Gravity:

2.76-2.88

Cleavage:

{001} perfect

Fracture:

Sectile

Color:

Colorless, green, brown

Streak:

White

Luster:

Vitreous, silky, pearly

Transparency:

Transparent/translucent

Common Habits:

Micaceous

Other Properties:

Notable Localities:

Russia; India; Ontario, Canada; Minas Gerais, Brazil

Uses:

Insulation material, lubricants, fireproofing

Associated Minerals:

Quartz, topaz, kyanite, spodumene, andalusite

Specimens:


Muscovite
Minas Gerais, Brazil


Muscovite
Orange, NH


Muscovite
Minas Gerais, Brazil


Muscovite
Chester Co., PA


Muscovite
Bahia, Brazil