The common characteristics of mica group minerals are: layered silicate minerals, monoclinic crystal system, a few trigonal crystal system, the crystals are pseudo-hexagonal columnar, plate and sheet; The aggregate is scaly and foliaceous. It has a set of extremely complete cleavage, along which it is easy to peel into sheets. Therefore, the shape of mica is usually regarded as sheet.

Mica is a very common rock-forming mineral, widely distributed in crystalline rocks. Its general chemical formula can be expressed as:

Later, with the development of science and technology, people gradually realized that mica minerals have high insulation, high temperature resistance, strong acid and alkali resistance, and mica also began to enter building materials, fire, plastics, paper, rubber, pearlite pigments and other industries. These are mainly Muscovite and phlogopite.