Talcum powder is a fine powder obtained by mechanically crushing tourmaline ore after impurities have been removed. Processed and purified tourmaline powder has a high negative ion generation rate and a high far-infrared emission rate. Tourmaline is also known as tormaline. The chemical formula for tourmaline is NaR3Al6Si6O18BO33(OH,F)4, which is a general term for a group of cyclic silicate minerals in the trigonal crystal system. In this formula, R represents a metal cation; when R is Fe2+, it forms a black crystal tourmaline. Tourmaline crystals are nearly triangular prismatic, with different crystal shapes at both ends, a columnar surface with longitudinal streaks, and are often found in columnar, needle-like, radiating, and massive aggregates. They have a glassy luster, a resinous luster on the fracture, and are semi-transparent to transparent. They do not have cleavage. The Mohs hardness is 7-7.5, and the specific gravity is 2.98-3.20. They possess piezoelectric and thermoelectric properties.