Asbestos is a naturally occurring mineral, which is often divided into two mineralogical groups, but not all varieties of asbestos have commercial use.
The first type is known as amphibole. The amphibole family includes amosite (“brown asbestos”), crocidilite (“blue asbestos”), tremolite, anthophyllite and actinolite. Among the various types of amphibole fibers, only crocidilite and amosite were incorporated into commercial products. However, “noncommercial” amphibole fibers (tremolite, anthophyllite and actinolite) may also have been present as contaminants in commercially used products that may include chrysotile asbestos, vermiculite and talc.
The other mineralogical group of asbestos is known as the serpentine group. It includes only the chrysotile variety of asbestos. Despite its hazardous nature, chrysotile was hugely popular with industry. Chrysotile accounts for over 90% of the asbestos that was used commercially in the United States.
Source: Pathology of Asbestos-Related Diseases (Victor L. Roggli et al. eds., 2004).