Natural pseudowollastonite: Crystal structure, associated minerals, and geological context

► Pseudowollastonite has been found as a rock-forming mineral in paralava veins. ► Pseudowollastonite-bearing paralavas resulted from natural combustion of methane. ► Crystallization was in shallow crust at T = 1265-1500 °C and was followed by quenching. ► The parent melts were larnite-normative, rich in Ca and depleted in both Mg and Fe. ► The mineral is very scarce in nature as it forms by joint action of the rare factors.