Mica is a mineral composed of silicates that together create thin, flat layers that are stacked together and come off as flakes or sheets. These flakes and sheets are heat resistant, light-reflective, resilient, lustrous, and range from transparent to opaque. Mica remains stable when it is exposed to electricity, moisture, light, and extreme temperatures. Mica minerals have a wide variety of types, including clear muscovite and purple lepidolite. Depending on which additional minerals are mixed with the silicate, mica is naturally available in an array of colors, including purple, black, brown, red, green, white, or clear.
With India and Russia being the largest producers, mica is used for thermal insulation, electronic equipment, decorative panels in lamps and windows, coil insulation, and windows used in stove heaters. The primary use is as a filler and extender in gypsum wallboard joint compounds when ground. Mica flakes can also be shaved very thin, adhered to the backing, and used as luxury wallcoverings.
Although they are the same minerals and composition, mica flakes are mined differently than mica sheets, with flakes being recovered from open pits where quartz, kaolin, and feldspar are mined. Sheets are recovered by sinking a shaft against pegmatite or via open-pit surface mining of pegmatite ore.