What is "potstone"

Steatite \Ste"a*tite\ (-t[imac]t), n. [Gr. ste`ar, ste`atos, fat, tallow: cf. F. st['e]atite.] (Min.) A massive variety of talc, of a grayish green or brown color. It forms extensive beds, and is quarried for fireplaces and for coarse utensils. Called also potstone, lard stone, and soapstone.

n. (context mineralogy English) A variety of steatite sometimes manufactured into culinary vessels.