The strength of asbestos comes from the way it is fabricated. It is made into very thin sheets that are then woven together to create a very strong material. This makes it ideal for use in products like brake pads and insulation where strength and heat resistance are important qualities.
Asbestos is a strong material because it is made of metal fibres. Metal fabrication produces very fine and strong metal fibres, and asbestos is made of these metal fibres. The strength of the metal fibres makes asbestos a very strong material.