Wollastonite

Calcium metasilicate mineral (CaSiO₃) often containing trace amounts of iron, magnesium, or manganese (H=4.5-5), white with elongated, fibrous or needle-like crystal structure, formed when impure limestone or dolomite is subject to high temperature and pressure, typically near igneous intrusions (skarns). Typically fluoresces yellow, orange-yellow, or deep orange under shortwave UV light.

Main Photo Credit:  "Wollastonite" by NRCan, 2026. Used with permission.