The generic name "asbestos" belongs to a group of minerals called "asbestiform" minerals. Asbestos is a fibrous material which is mined from serpentine rock. Basically, rock was mined and crushed. When the rock was crushed, fibrous stands of asbestos were extracted from the rock. The strands were put in bags and shipped to manufacturing facilities were the asbestos was used as an ingredient in insulation and other materials. The three most commonly used forms of asbestos that were used in product manufacturing were:
Chrysotile - (White Asbestos) This was the form of asbestos used predominantly in products manufactured in the United States. Although small amounts of chrysotile were mined in the United States, the overwhelming majority of the asbestos was mined in Canada and then shipped into the United States.
Amosite - (Gray Asbestos) Amosite asbestos was used to a lesser extent than Chrysotile. Most of the amosite asbestos used int he United States was mined in South Africa.
Crocidolite - (Blue Asbestos) This form of asbestos was the least used in commercial products. Approximately 10% of the asbestos used in the United States was crocidolite.
Chrysotile asbestos is known as serpentine because it is found in serpentine rock. Amosite asbestos is an amphibole. Although asbestos products have not been used in construction since approximately 1975, the products in place present a clear danger to men involved in repair work in the demolition of structures containing asbestos products.