Mica

Mica, group of minerals that split into thin, flat sheets of aluminum, silicon, and oxygen. Varieties of mica include muscovite, biotite, phlogopite, and lepidolite. Mica can be found in glistening rocks such as igneous and metamorphic. In its sheet, scrap, or ground form, it has a wide variety of industrial uses. Most scrap mica is produced in the United States.