Certain minerals that have a fibrous structure, are heat resistant and chemically inert, possess high electrical insulating qualities, and are of sufficient flexibility to be woven. The two main groups are serpentine and amphiboles. Asbestos proper is actinolite. Chrysotile is fibrous serpentine; amosite is fibrous anthophyllite; crocidolite is fibrous soda-amphibole. Used in fireproof buildings, insulating, paint materials, brake linings, and clutches, and as insulation against heat, electricity, and acid.