[Gk. asbestos, that cannot be quenched.] A mineral substance, unaffected by fire, occurring in long and delicate fibres, or in fibrous masses or seams, usually of a white, gray, or green-gray color. The finer varieties have been wrought into gloves and cloth which are incombustible. The cloth has been re commended for firemen's clothes. Asbestos is also employed in the manufac-ure of iron safes, fireproof roofing, and lamp-wicks, and is used, as a poor conductor of heat, for packing around steam pipes, valves, etc. The largest mines are in the province of Quebec, Canada.