The chemical composition of talc is Mg3[Si4O10](OH)2, and the crystal belongs to the layered silicate mineral of triclinic system.Pseudo-hexagonal single crystals are rare, and they are usually dense massive, bladelike, fibrous or radial aggregates.White or various light colors, streaks are often white, fatty luster (lumpy) or pearl luster (patchy aggregate), translucent.Mohs hardness 1, specific gravity 2.6-2.8.