Wollastonite is chemically a Calcium Meta Silicate (CaSiO3), it is a naturally occurring white & acicular (needle shaped) mineral, with mohs hardness of 4.5. In addition to Wollastoniteâ??s unique morphology, it is alkaline, inert, has low loss on ignition, low water solubility, low co-efficient of linear thermal expansion and a melting point of 15400c. It also improves tear strength, dielectric properties and retains mechanical properties at elevated temperatures.