KAl2(AlSi3O10)(OH)2Monoclinic
Mica
KAl2(AlSi3O10)(OH)2
SilicatesChemical FormulaKAl2(AlSi3O10)(OH)2
Crystal SystemMonoclinic
Mohs Hardness2.5
Specific Gravity2.8
ColorColorless, silver, brown, green
LusterVitreous to pearly
StreakWhite
CleavagePerfect basal
FractureFlexible
Occurrence
Found in igneous and metamorphic rocks. Muscovite and biotite are common varieties.