Mica is crystallized in the monoclinic system often as flat pseudo-hexagonal crystals and is dispersed in igneous rocks as thick sheets. It is also found as strips in schist and gneiss and as clay in sedimentary rocks. Mica with a perfect cleavage in one direction is separated as sheets with irregular edges, but is strong and elastic. Mica is observed in colorless, gray, pale green, brown, yellow, pinkness or purple colors. It remains a white footprint and shows glassy or pearly luster. It varies from opaque to translucent. Thin mica sheets are transparent. It has a hardness of 2-3 Mohs with a specific gravity of 2.7-3.1.
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