Chrysotile
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Chrysotile is an asbestiform sub-group within the serpentine group of minerals. There are three known species of chrysotile: clinochrysotile (which is monoclinic), orthochrysotile (which is orthorhombic) and parachrysotile (which is also an orthorhombic polymorph). These varieties are all phyllosilicates. The chemical formulae for the three are the same: Mg3(Si2O5)(OH)4 with variable iron as Fe2+ substituting for magnesium. Chrysotile varies in color from gray-white to golden yellow to green. It has a hardness of 2.5 - 3. The three varieties form the fibrous members of the serpentine group and have been extensively mined as asbestos.
Clinochrysotile is the monoclinic form of chrysotile and likely the most common variety. Like the other two species of chrysotile (orthochrysotile and parachrysotile) it is very difficult to distinguish from the other species. Its type location is unknown although the chrysotile from Asbestos, Quebec, Canada is largely clinochrysotile.
Orthochrysotile is the orthorhombic form of chrysotile and is more common than the other orthorhombic form parachrysotile. Like the other two species of chrysotile (clinochrysotile and parachrysotile) it is very difficult to distinguish from the other species. Its type location is found in Silesia.
Parachrysotile is a second orthorhombic form of chrysotile. Like the other two species of chrysotile (orthochrysotile and clinochrysotile) it is very difficult to distinguish from the other species. Its type location is Québec, Canada.
References
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