This chapter provides an overview of the historical context of asbestos use, the geological and mineralogical features of asbestos, and the identification and characterization of asbestos. Asbestos is a commercial term that refers to a group of silicate minerals that occur as very fine fibers that have been exploited for their unique physical characteristics. The use of asbestos in industry led to these minerals being incorporated into a wide variety of products. A significant amount of work has been done to characterize the geological formations that asbestos can be found in as well as to understand the mineralogical differences between the various asbestos types.