Talc

Talc, [Mg₃Si₄O₁₀(OH)₂], hydrous magnesium silicate mineral occurring in metamorphic rocks, chiefly in the United States, USSR, France, and Japan. It has a layer structure resembling that of mica, and is extremely soft. Talc is translucent but not transparent. It is used in ceramics, roof insulation, cosmetics, as an insecticide carrier, and as a filler in paints, paper, and rubber. Impure, massive talc is called soapstone.