Soap-Earth, or Steatites, L. a species of fossil, which abounds in Devonshire, Cornwall, and the islands in the vicinity of the Lizard Point. It is generally of a white, or grey colour, intermixed with greenish or yellowish shades; is composed of very fine particles; of a firm, equal, and regular texture ; and is very heavy. Its surface is smooth and glossy ; it feels soft and greasy ; and neither melts in the mouth, nor adheres to the tongue, or stains the fingers.

This mineral may be formed into a paste with water, which is easily worked on the potter's wheel; and if, thus manufactured, it be exposed to an intense heat, it becomes so hard as to emit fire, when stricken against steel.

The soap-earth possesses similar properties with Fuller's-earth, and is employed for the purpose of cleansing woollen cloths from grease: it does not, however, work so easily as clays ; and, when digested with vitriolic acid, it forms a salt somewhat resembling that obtained by evaporating Epsom -water.