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Asbestos is the name given to a group of naturally occurring fibrous mineral that can be found in sedimentary deposits throughout the world. The word asbestos is derived from greek meaning "not extinguishable," referring to its fire retardant properties. These fibers have been used throughout history for a number of different uses. Asbestos can be classified into two groups, amphiboles and serpentine, based the crystal structure of the fibers. The class of minerals know as asbestos contains six different minerals. These minerals are:  - Chrysotile- or "white asbestos" is by far the most commonly encountered form of asbestos. Studies suggest that Chrysotile could account for over 90% of all of the asbestos that is currently in place in the United States. Chrysotile is a soft fibrous silicate of the serpentine asbestos family with tremendous tensile strength and insulative properties. Chrysotile is an extremely versitile mineral and has in the past been spun into thread or woven into clothing.
 - Amosite- or "brown asbestos" is considered to be one of the most hazardous forms of asbestos, ranking just behind Crocidolite or "blue asbetsos." At one point in time Amosite was the second most common form of asbestos, accounting for almost five percent of all asbestos used in commercial buildings and factories. Amosite was mostly used for its insulative and fire-proofing properties in ceiling and wall tiles.
 - Crocidolite- or "blue asbestos" was the least frequently used form asbestos, accounting for about four percent of all asbestos used in the U.S. Crocidolite is a member of the amphibole family and naturally occurs in long straight bundles. These straight stiff fibers can easily become lodged in the lungs if inhaled. Crocidolite was found to be far less fire resistant than other forms of asbestos which caused it to be used less frequently. Crocidolite is was mostly used in the production of asbestos containing cement products.
Only Chrysotile, amosite, and crocidolite were used in industrial applications. The other three forms anthrophyllite, tremolite, and actinolite are very rare and were never used on an industrial level.
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