mineral
Wollastonite
Calcium Inosilicate Mineral, CaSiO3
Hardness of 4.5 to 5 on the Mohs scale, typically white, gray, or pale cream in color with a vitreous to pearly luster. It crystallizes in the triclinic system, features two perfect directions of cleavage, and has a specific gravity of 2.86 to 3.09.
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Physical properties
Hardness of 4.5 to 5 on the Mohs scale, typically white, gray, or pale cream in color with a vitreous to pearly luster. It crystallizes in the triclinic system, features two perfect directions of cleavage, and has a specific gravity of 2.86 to 3.09.
Formation & geological history
Formed through thermal metamorphism of siliceous limestones and dolostones, or through contact metamorphic processes where impure limestone interacts with hot magmatic fluids.
Uses & applications
Used widely in ceramics, paint formulation, plastics as a reinforcing filler, metallurgy as a flux, and in the manufacture of friction products like brake pads.
Geological facts
Wollastonite is named in honor of the English chemist and physicist William Hyde Wollaston. Its acicular (needle-like) crystal habit makes it an excellent industrial replacement for asbestos in certain applications.
Field identification & locations
Can be identified in the field by its characteristic bladed or acicular crystal aggregates, white color, and association with skarn deposits in contact metamorphic zones.
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