Asbestos is a naturally occurring mineral once used in the manufacture of building materials because of its fireproof qualities. The strength and resilience of asbestos made it a good choice for industrial purposes but the fibers can penetrate bodily tissues such as the lungs and cause tumors. More than 100 mineral fibers have asbestos-like qualities but only six have been identified as asbestos and regulated by the U.S. government.
The asbestos mineral is made up of long chains of silicon and oxygen which gives it a fibrous nature. Each type is different in physical and chemical properties depending upon the individual components of calcium, magnesium or iron. There are two main groups of asbestos. The serpentine group, which includes chrysotile asbestos, is made up of minerals that have a layered form and curly fibers. The amphibole group, which consists of the other five types of asbestos, is made up of minerals that have a chain-like structure.
Six Types of Asbestos
• Chrysotile asbestos, also known as “white asbestos,” is the most common type. It consists of very fine and flexible white fibers. Its crystals are formed in sheets and form a serpentine pattern. Because of its wide use, it accounts for the majority of health related problems around the world.
• Actinolite asbestos is usually green, gray or white. It is a common mineral in metamorphic rocks. It is closely related to tremolite asbestos but has more iron than tremolite. It has not been heavily used in commercial or industrial production but may be a contaminant in asbestos products. Non-fibrous forms of actinolite do not pose the same health issues as other types of commercially used asbestos.
• Amosite asbestos has straight brittle fibers and is often called “brown asbestos” because the colors of its fibers range from light gray to brown. Once used for insulating materials, it was the second most common type of asbestos. Its use has since been banned in most countries.
• Anthophyllite asbestos has brittle white fibers made of crystals with a chain-like appearance. It is formed by the breakdown of talc in ultramafic rock and is not usually used for commercial purposes. However, the fibers can be found among natural minerals that expand with heat such as vermiculite, a common ingredient in gardening soil and insulation.
• Crocidolite asbestos is known as “blue asbestos” and is easily identifiable by its straight blue fibers. Believed to be the most dangerous form of asbestos, it is found naturally in Australia, Bolivia, Canada, South Africa and the former Soviet Union.
• Tremolite asbestos is commonly found in metamorphic rocks and ranges in color from creamy white to dark green. Though not used as extensively as chrysotile, it has been used for industrial purposes and has been found in some household products such as talcum powder.