talco

Talco, or talc, is a mineral composed of hydrous magnesium silicate with the chemical formula Mg3Si4O10(OH)2. It is a phyllosilicate with a layered structure and a hardness of 1 on the Mohs scale, making it one of the softest minerals. Talc is usually white or gray and has a pearly to chalky luster; impurities can yield other colors. It cleaves easily along the {001} plane, enabling sheet-like fragmentation.

Talc forms by metamorphism of ultramafic rocks and by hydrothermal alteration of magnesium-rich rocks. It commonly occurs in soapstone and is often found with minerals such as serpentine and magnesite. Major deposits have been mined in China, India, Italy, the United States, and Finland. Some talc deposits have been associated with asbestos minerals, requiring careful separation to produce safe commercial products.

Industrial uses are diverse. The powder is widely used as a filler and a lubricant in plastics, paints, paper, and ceramics, and as a buffering, stabilizing agent in rubber. The cosmetic form, talcum powder, is used for skin care and fragrance carriers. Talc also serves as a high-temperature, chemical-resistant filler in various products.

Safety and regulation emphasize purity. Because talc deposits may contain asbestos minerals, consumer cosmetic talc must be asbestos-free in many jurisdictions. Inhalation of talc dust can irritate airways, so workers’ exposure is controlled, and purity standards require testing for contaminants. Environmental considerations in talc mining include dust control and land rehabilitation.