Asbestos (pronounced , or ) is a set of six naturally occurring
silicate minerals, which all have in common their
eponymous asbestiform habit: long (roughly 1:20
aspect ratio), thin
fibrous crystals, with each visible fiber composed of millions of microscopic "fibrils" that can be released by
abrasion and other processes. They are commonly known by their colors, as
blue asbestos,
brown asbestos,
white asbestos, and
green asbestos.