These phyllosilicates are also called isinglass.  Members exhibit monocline crystals and have excellent basal cleavage.  
These phyllosilicates are also called isinglass.  Members exhibit monocline crystals and have excellent basal cleavage.  Types include iron-rich biotite, lepidolite, and muscovite and class members are used as electrical insulation and Christmas tree snow. For ten points, identify the hydrous silicates of aluminum and potassium that are composed of many thin sheets.
These phyllosilicates are also called isinglass.  Members exhibit monocline crystals and have excellent basal cleavage.  
mica