TalcTalc is a mineral composed of hydrated magnesium silicate
with the chemical formula H2Mg3(SiO3)4 or Mg3Si4O10(OH)2. It
occurs as foliated to fibrous masses, its monoclinic crystals
being so rare as to be almost unknown. It has a perfect basal
cleavage, the folia non-elastic although slightly flexible. It
is sectile and very soft, with a hardness of 1. It has a
specific gravity of 2.5-2.8, a waxlike or pearly lustre, and is
translucent to opaque. Its color ranges from white to gray or
green and it has a distinctly greasy feel. Talc is a metamorphic
mineral resulting from the alteration of silicates of magnesium
such as pyroxenes, amphiboles, olivine and other similar
minerals. It is usually found in metamorphic rocks, often of a
basic type due to the alteration of the minerals mentioned
above. A coarse grayish-green talc has been called soapstone or
steatite and has been used for stoves, sinks, electrical
switchboards, etc. Talc finds use as a cosmetic (talcum powder),
as a lubricant, and as a filler in pa