Jet, a mineral of a perfectly black color, capable of being easily cut and carved and taking a very beautiful polish. It was first found in Asia Minor. In Great Britain it is obtained chiefly at Whitby in Yorkshire. Very large quantities are found in France, where it gives employment to many of the people of Aude. It is made into rosary beads, crosses and other ornaments. As a material for mourning jewelry it is especially valuable, and for that purpose is largely used. Imitations of jet are made from hardened india-rubber, called vulcanite or ebonite, and from glass.