What is asbestos?
Asbestos is the name given to a group of six different fibrous minerals (amosite, chrysotile, crocidolite, and the fibrous varieties of tremolite, actinolite, and anthophyllite) that occur naturally in the environment. One of these, namely chrysotile, belongs to the serpentine family of minerals, while all of the others belong to the amphibole family. All forms of asbestos are hazardous, and all can cause cancer, but amphibole forms of asbestos are considered to be somewhat more hazardous to health than chrysotile. Asbestos minerals consist of thin, separable fibers that have a parallel arrangement. Nonfibrous forms of tremolite, actinolite, and anthophyllite also are found naturally. However, because they are not fibrous, they are not classified as asbestos minerals. Amphibole asbestos fibers are generally brittle and often have a rod- or needle-like shape, whereas chrysotile asbestos fibers are flexible and curved. Chrysotile, also known as white asbestos, is the predominant commerci
Asbestos is the name for a group of fibrous minerals that are mined and mixed into building materials. Asbestos is very resistant to heat and chemicals. Asbestos has been used in a wide range of manufactured goods including floor and ceiling tiles, coatings, texturing materials and thermal insulation. Currently, asbestos is used only in products where another material has not been found to replace it. Generally, asbestos is not a health risk when bound together with a substance that prevents the fibres from entering the environment.
Asbestos is a mineral. It is mined in much the same way that other minerals, such as iron, lead, and copper, are. Asbestos is composed of silicon, oxygen, hydrogen, and various metal cations (positively charged metal ions). There are many varieties of asbestos: the three most common are chrysotile, amosite, and crocidolite. Chrysotile fibers are pliable and cylindrical, and often arranged in bundles. Amosite and crocidolite fibers are like tiny needles. The first commercial asbestos mine — a chrysotile mine — opened in Quebec, Canada, in the 1870’s. Crocidolite asbestos was first mined in South Africa during the 1980’s. Amosite asbestos also comes from Africa and was first mined in 1916. Unlike most minerals, which turn into dust particles when crushed, asbestos breaks up into fine fibers that are too small to be seen by the human eye. Often individual fibers are mixed with a material that binds them together, producing asbestos containing material (ACM).
Asbestos is a carcinogenic mineral that was commonly used industrially because of its insulating properties (resistant to heat or fire and certain chemicals). An estimated 100 million workers were exposed to asbestos throughout the 20th century in the United States alone. Asbestos was regulated under section 112 of the Clean Air Act in 1970 because of widespread concern over the health hazards associated with exposure, something that had been known by manufacturers since before World War II.
Asbestos is a commercial term for a number of minerals that have a fibrous or an acicular (needle – like habit). These include chrysotile – a serpentine mineral (a hydrous phyllosilicate) and the following amphiboles; amosite – a variety of gruenerite, crocidolite – a variety of riebeckite, fibrous anthophyllite, and fibrous tremolite and actinolite. Chrysotile was the most important mineral used in 95% of the asbestos. Tremolite and actinolite were not ever comercially important and anthophyllite is not now comercially important. The first use of anthophyllite from Finland was as a strengthener for pottery from 2500 B.C. The Romans used asbestos for oil lamp wicks and as cremation cloths. The principal uses in the US were for cement pipe, flooring products, friction materials, and roofing products. The major health problem with the material is that if the acicular needles of asbestos get into the atmosphere, they can cause tumors to form in the pleura of the lungs. The Mineralogical S
