Wollastonite with pen for scale. From the mineral collection of Brigham Young University Department of Geology, Provo, Utah, Mineral Specimens 1196. Courtesy of the U.S. Geological Survey Denver Library Photographic Collection. (Photo by Andrew Silver.)

Formula: CaSiO3 Triclinic


Wollastonite forms in highly metamorphosed marbles or calc-silicate rocks.

IRON COUNTY: Wollastonite occurs as a fine-grained mix of intergrown fibers in an algal limestone deposited between basaltic lava flows. in outcrops northwest of Upson Lake. The metamorphism is likely due to the effects of the nearby Potato River Gabbro. (Cannon, 1996).

MARATHON COUNTY: Wollastonite forms tiny prisms in the agrellite-bearing pegmatite associated with the Stettin pluton. (Falster, et. al., 2000).