Wollastonite

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Wollastonite (CaSiO3) is a mineral which can develop as skarn deposits (in contact metamorphic situations) and as a primary magmatic mineral (associated with carbonatites). The mineral cleaves into particles with needle-like shapes, having great strength. Wollastonite is a high-performance mineral filler in paint, plastics, and thermal board; it also is a substitute for asbestos and an additive to ceramics, where it imparts strength and rapid firing, and inhibits shrinkage and warping. The mineral has several unique properties which create continued growth in its demand. Wollastonite reduces energy costs when used to replace sand and limestone in glass and glass fiber by lowering the fusion temperature. Surface-modified wollastonite powders in fine and ultrafine grades are used increasingly as plastic filler.

In Arkansas, wollastonite formed along the contact zone of the Potash Sulphur Springs igneous intrusion and the Arkansas Novaculite, where carbonate-rich fluids from the intrusion reacted with silica-rich novaculite. There has been no mining of wollastonite from Arkansas and the known deposits have not been commercially evaluated. Resources are limited, to one location, but wollastonite could be a by-product if the host rock was processed for other mineral value.

References

Milton, Charles, 1984, Miserite, a review of world occurrences with a note on intergrown wollastonite, in McFarland, J. D., III, and Bush, W. V., eds., Contributions to the geology of Arkansas, v. II,: Arkansas Geological Commission Miscellaneous Publication 18-B, p.97-114.

Williams, J. F., 1891, The igneous rocks of Arkansas: Arkansas Geological Survey Annual Report for 1890, v. II, 457 p.

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