Asbestos is a generic term referring to six naturally-occurring fibrous silicate minerals found predominantly in metamorphic rock. Asbestos minerals crystallize in narrow veins as parallel bundles of tiny fibers. These fibers are very small, and may remain airborne for several hours when broken-up and dispersed into the air.
Asbestos is very resistant to acids and heat, and has high tensile strength.
Chrysotile fibers are hollow and pliable. Amphibole fibers are hard and straight. Asbestos' resistance to chemicals and heat, high tensile strength, and low cost made it a very attractive ingredient in thousands of building and thermal insulation products. Some typical uses of asbestos include cement pipes, vinyl floor tiles, boiler insulation, automotive brakes and clutches, electric wiring insulation, structural fireproofing and roof shingles. In the 1970's, the U.S. began banning the use of asbestos in most building products due to studies confirming the harmful health effects caused by exposure to airborne asbestos.