Talc: A very soft, soapy-feeling mineral that is a silicate of magnesium, sometimes with small amounts of aluminum silicate.
Talc is used in making dusting powder (talcum powder), in cosmetic preparations, and as a filter aid in pharmacy.
The inhalation of talc can lead to a chronic lung disease called talcosis which is related to silicosis. It occurs in workers exposed to talc mixed with silicates.
Talcum powder often used to contain traces of asbestos (because talc and asbestos form under similar circumstances and are commonly found together in the earth). Since asbestos can cause cancer, it is now removed from talcum powder.