French, from di- + Greek opsis appearance — more at optic
First Known Use: circa 1808
Common silicate mineral in the pyroxene family. Diopside is a calcium and magnesium silicate (CaMgSiO) that occurs in metamorphosed siliceous limestones and dolomites, in skarns, and in igneous rocks. It is also found in small amounts in many chondritic meteorites. Clear specimens of good green colour are sometimes cut as gems.