WOLLASTONITE

white, glassy silicate mineral that commonly occurs as masses or tabular crystals with other calcium-containing silicates (e.g., diopside, tremolite, garnet, and epidote) in metamorphosed limestones. Deposits are found in Ciclova Romna, Rom.; Monte Somma, Italy; and Pargas, Fin. Occurrences in the United States include Utah; Isle Royale, Mich.; Riverside, Calif.; and Essex county, N.Y., where it is mined. For detailed physical properties, see silicate mineral (table). Wollastonite, the most common of the three forms of calcium silicate, CaSiO3, is used in many ceramic products, including floor and wall tiles, electrical insulators, and porcelain fixtures. It is also used in welding rod coatings and in paints.