Talc is a layered silicate mineral containing Mg3[Si4O 10](OH) 2. Crystals belong to the triclinic system, and pseudo-hexagonal sheet-like single crystals are rare, often in dense blocks, leaves, fibers or radial aggregates. It is white and gray, and is often dyed in various colors because it contains impurities such as iron, manganese and nickel. Mohs hardness is 1. The cleavage of the bottom surface is completed. Cleavage surface is pearly luster with satiny feeling, and its specific gravity is 2.58 ~ 2.83. It is resistant to fire and acid. Soft, smooth and glossy talc is used as a raw material for carving handicrafts, as a filler in paper and rubber industries, and as a refractory in metallurgical industry. Talc porcelain is made of talc, which has good dielectric properties and mechanical strength. It is a high-frequency and ultra-high-frequency electric porcelain insulating material. Talc is a hydrothermal alteration mineral, which is usually formed by hydrothermal alteration of magnesium-rich rocks. Serpentine peridotite can also form talc under the action of hot water solution invaded by late acid and CO2, so talc often presents the illusion of olivine, enstatite, amphibole, tremolite and other minerals.

Most of them are massive aggregates. They are irregular blocks. They are white, yellowish white or light blue gray with waxy luster. They are soft and delicate, smooth to the touch, have no hygroscopicity, and will not collapse when exposed to water. They are odorless and tasteless.

Sexual taste and meridian tropism are sweet, light and cold, and belong to bladder, lung and stomach meridians.

Functions and indications: diuresis for stranguria, clearing heat and relieving summer heat, eliminating dampness and healing sores. Used for heat stranguria, stranguria, astringent pain due to urine heat, polydipsia due to summer dampness, and damp-heat watery diarrhea; External treatment of eczema, wet sore and miliaria.

Store in a dry place.