More common varieties include biotite and muscovite.  
This type of mineral is found in sedimentary, igneous, and metamorphic rock.  A group of hydrous potassium, aluminum silicate minerals, there are 28 varieties, including glauconite, which, unlike the other varieties, usually appears as pelletlike grains.  More common varieties include biotite and muscovite.  FTP, identify these minerals most widely known for exhibiting perfect cleavage into flexible sheets and shares its name with a book of the Old Testament.
This type of mineral is found in sedimentary, igneous, and metamorphic rock.  
mica