Occurrence and Compostion
 Wollastonite is found in some high-grade marbles, typically associated with diopside and garnet. It is a pyroxenoid with composition generally quite close to CaSiO3.

 Wollastonite is colorless with moderate to high relief and may show one good cleavage. It is usually elongate and/or bladed.

Important properties
 ·Appearance and habit - Wollastonite forms blades, columns and, less commonly, fibers
 ·Color - clear
 ·Interference colors - Birefringence is low; maximum interference colors are first order yellow.

Similar minerals
 ·Can be easily confused with a number of other clear Ca- and Ca-Mg silicates found in marbles.
 ·Diopside has greater relief, larger 2V, and typically shows well-developed pyroxene cleavage.
 ·Zoisite and light colored epidote have higher relief and 2V.

Wollastonite, Diopside and Garnet in a Skarn

This photograph shows a large grain of wollastonite (clear, diamond shaped, center of photo), a smaller grain of diopside (higher relief, upper left part of photo) and garnet (isotropic; brownish PP; extinct XP). This rock comes from a classic wollastonite deposit near Willsboro, New York. The field of view is about 2 mm.