Mica is a metamorphic mineral that comes from volcanoes and hydrothermal vents. It is easily recognized by its thin crystal layers that peel off in sheets. Mica is very shiny and is responsible for the glittery effect in composite rocks such as granite, gneiss and slate.
Mica is composed of silicon and oxygen. Biotite, muscovite and boromuscovite are three common variations. Mica is an excellent insulator and has many electrical applications. Mica is white, yellowish, green or gray, and can be found on most continents. The largest deposits are found in India, South Dakota, Russia and Brazil. In addition to its use in electronics, mica has many artistic applications.