n.
A group of important rock-forming silicate minerals of variable composition, among which calcium-, magnesium-, and iron-rich varieties predominate.
Common pyroxenes belong to either the low-calcium enstatite-(ortho)ferrosilite series, (Mg,Fe)SiO 3 , or the high-calcium diopside-hedenbergite series, Ca(Mg,Fe)Si 2 O 6 . Rare pyroxenes include jadeite , aegirine , and johannsenite. See also enstatite .