Definition. - A native hydrous magnesium silicate, official under the same name in the German Pharmacopoeia.

Many of the commercial talcum powders contain talc and boracic acid.

Properties. - Talc occurs as a grayish-green solid with waxy luster, or a white or pale-gray powder. It feels greasy to the touch, hence it is popularly called soap-stone. It is used as a dusting-powder, and in some pill-masses.