Pyroxene is the name of a group of dark-colored rock-forming minerals found in igneous and metamorphic rocks throughout the world. They form under conditions of high temperature and/or high pressure.
Augite, diopside, jadeite and spodumene are four of the best-known members of the pyroxene group; however, the pyroxene group has many other members.
Pyroxene minerals are defined by their chemical composition and crystal structure. Their generalized chemical composition is described by the formula and comments below.
XYZ2O6
Where X can be one or more of the following: Ca, Na, Fe++, Mg, Zn, Mn, or Li
Where Y can be one or more of the following: Mg, Fe+++, Fe++, Cr, Al, Co, Mn, Sc, Ti, or Vn
Where Z can be Si, Al, or a combination of both
A wide range of cation substitutions can occur in the X and Y positions.
