Is mica a rock-forming mineral?

Mica is a rock-forming mineral, which is a general term for layered structure aluminosilicates composed of potassium, aluminum, magnesium, iron, lithium, etc.
Mica generally has polymorphisms, among which the monoclinic crystal system is the most common, followed by the trigonal crystal system. Mica usually takes the form of pseudo-hexagonal or rhombus-shaped plate, flake, or columnar crystals. The color of mica varies with its chemical composition, mainly becoming darker as the iron content increases. The characteristics of mica are insulation and high temperature resistance.
The most common mineral species among the mica group minerals include biotite, muscovite, phlogopite, lepidolite, sericite, etc. The most widely used in industry are muscovite and phlogopite. Because of its unique crystal structure and physical and chemical properties, mica is widely used in electrical and electronics, insulation materials, cosmetics, coatings, new energy and other fields.

Mica has very high insulation and thermal insulation properties, good chemical stability, and resistance to strong acids, strong alkali and pressure. Therefore, it is an important raw material for manufacturing electrical equipment and can also be used as an insulating material in hair dryers. Mica also has birefringence ability, so it is also an optical instrument material for manufacturing polarizers.