Mica
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/69455149@N00">Pascal Terjan</a> from London, United Kingdom (CC BY-SA 2.0)
Mineral NameMica
Chemical FormulaKAl2(AlSi3O10)(OH)2 (Muscovite, a common mica)
Mohs Hardness2.5
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite
CleavagePerfect basal cleavage in one direction, forming thin elastic sheets.
Fractureuneven
Specific Gravity2.8
Colorssilvery-white, brown, black, green, pink
Transparencytransparent
Type LocalityWorldwide, common in granites, pegmatites, and metamorphic rocks.
Mineral GroupSilicates
Useselectrical insulation, thermal insulation, filler in paints and plastics, cosmetics
Associated Mineralsquartz, feldspar, tourmaline, garnet
Raritycommon
Description
The image displays a large aggregate of mica crystals, characterized by their distinct layered, platy structure and a silvery-brown hue with a pearly to vitreous luster.
Geological Context
Mica minerals are common in igneous rocks like granites and pegmatites, and are particularly abundant in metamorphic rocks such as schists and gneisses, forming under various pressure and temperature conditions.
