A soft mineral of a soapy feel and a greenish, whitish, or grayish color, usually occurring in foliated masses. It is hydrous silicate of magnesia. Steatite, or soapstone, is a compact granular variety.
- A fine-grained white, greenish, or gray mineral, Mg3Si4O10(OH)2, having a soft soapy feel and used in talcum and face powder, as a paper coating, and as a filler for paint and plastics.
- To apply this substance to (a photographic plate, for example).