• (n.) A variety of steatite sometimes manufactured into culinary vessels.
Pot'stone` noun (Min.) A variety of steatite sometimes manufactured into culinary vessels. 
Potstone (Lapis ollaris) is a species of talc containing an admixture of chlorite. It is green in colour and varies in shade, greasy and soft but hardens on exposure to the air. It's English name comes from its capability to be turned into vases and pots by turning.