Pyroxene group

thumb|Pyroxene (diopside) crystals from [[Afghanistan]]

Rhodonite is a manganese inosilicate, with the formula (Mn, Fe, Mg, Ca)SiO3, and member of the pyroxenoid group of minerals, crystallizing in the triclinic system. The term rhodonite was first introduced by Germar. . It commonly occurs as cleavable to compact masses with a rose-red color often tending to brown due to surface oxidation. The rose-red hue is caused by the manganese cation (Mn). thumb|left|Pink rhodonite contrasting with black manganese oxides is sometimes used as gemstone material as seen in this specimen from Humboldt County, [[Nevada.]] Rhodonite crystals often have a thick tab

Pyroxmangite has the general chemical formula of MnSiO3. It is the high-pressure, low-temperature dimorph of rhodonite.

Pyroxferroite (Fe2+,Ca)SiO3 is a single chain inosilicate. It is mostly composed of iron, silicon and oxygen, with smaller fractions of calcium and several other metals. Together with armalcolite and tranquillityite, it is one of the three minerals which were discovered on the Moon during the 1969 Apollo 11 mission. It was then found in Lunar and Martian meteorites as well as a mineral in the Earth's crust. Pyroxferroite can also be produced by annealing synthetic clinopyroxene at high pressures and temperatures. The mineral is metastable and gradually decomposes at ambient conditions, but thi