Pigeonite

Pyroxene mineral

Pigeonite

Pigeonite is a mineral in the clinopyroxene subgroup of the pyroxene group. It has a general formula of (Ca,Mg,Fe)(Mg,Fe)Si2O6. The calcium cation fraction can vary from 5% to 25%, with iron and magnesium making up the rest of the cations.

From Wikipedia, under CC BY-SA. More on occurri.