Asbestos is a unique mineral that can be spun into thread and woven into cloth. Its fibres are fireproof. There are two common sources of asbestos: chrysotile (commonly known as a fibrous variety of serpentine) and amphibole. Chrysotile, from which most commercial asbestos is obtained, has fibres that run across the veins in which it occurs.

There is now a consensus that chrysotile is less injurious health wise than amphibole asbestos. Chrysotile is generally referred to as 'white asbestos'