Wollastonite(redirected from Calcium metasilicate)
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(named after the English scientist W. H. Wollaston, 1766-1828), also tabular spar, a silicate mineral with a chain structure and a circular radical. Its chemical formula is Ca3(Si3O9), and it sometimes contains traces of iron. Wollastonite crystallizes in a triclinic system, forming flat tabular crystals as well as radiated and conchoidal aggregates; its color is white and sometimes pink. It has a hardness of 5-5.5 on the mineralogical scale and a density of 2,780-2,920 kg/m3. Wollastonite is formed by contact and plutonic regional metamorphism of limestones.