talc

Talc is a hydrated magnesium silicate mineral with the chemical formula Mg3Si4O10(OH)2. It has a soft, soapy feel and a pearly luster, typically white to gray-green. It ranks 1 on the Mohs scale for hardness and exhibits perfect basal cleavage, allowing it to fracture into thin sheets.

Talc forms by metamorphism of magnesium-rich rocks and by hydrothermal alteration of ultramafic rocks, and it occurs in talc-rich rocks such as talc schist and soapstone. It is distributed worldwide, with major sources in China, India, Brazil, the United States, and Finland.

Uses: Talc is widely used as a filler and coating in paper, plastics, paints, and ceramics, and as a lubricating agent and anti-caking agent. In cosmetics, processed talc is used to make talcum powder for personal care products; pharmaceutical-grade talc serves as an inert filler in pills and topical formulations.

Safety and regulation: Some natural talc deposits can contain asbestos, which has been associated with health concerns in the past. Modern cosmetic-grade talc is tested to be asbestos-free in many jurisdictions. Inhalation of talc dust can irritate the respiratory tract, and occupational exposure limits apply in manufacturing settings.