Steatite

A rock composed almost exclusively of the mineral talc (Mg3Si410(OH)2). It is similar in composition to serpentine, but contains less water. It is quite soft with a soapy feel (giving it its other name of soapstone). Steatite is a common material for scarabs and seals; these are generally glazed, and in the firing steatite turns to the far harder material enstatite