Soapstone

(sõp's tun,) or STEATITE. (Min.) A hydrated silicate of magnesia, with a smooth greasy feel like that Society of soap, and so soft as to yield to the nail. It is a ma ive variety of talc, which, when pure and compact, is much used as a refractory material for lining furnaces, being infusible in any ordinary furnace heat. It is easily turned in the lathe, or cut with knives and saws, and is made into culinary ve els. When very strongly heated, S. loses the small portion of combined water which it contains, and becomes harder and susceptible of polish. In this state it is made into jets for gas burners, which have the advantage of not being liable to rust or corrosion. When reduced to powder, it is used like plumbago as a lubricator and to diminish Society friction, as well as to give a surface to some kinds of paper-hangings. [s. 835]