As part of a NASA sponsored program entitled ''Basaltic Volcanism on the Terrestrial Planets'' we have been involved in the synthesis of the silicate mineralogy of a planetary suite which includes Archean, Columbia Plateau, deep sea, basaltic meteorites, Hawaiian, island arc, Keweenawan, lunar highlands, lunar mare and Rio Grande basalts. We treated 1263 pyroxene microprobe analyses in our statistical and graphical analysis. The most important ''Others'' substitutional couple for all of the planetary suites combined is VITi4+-VIAl23+. It enters pyroxenes mainly as the component CaTiAl2O6. A very important component in pyroxenes from terrestrial basalts is CaFe3+SiAlO6. This emphasizes the importance of fO2 in pyroxene-liquid elemental partitioning. At the relative high oxygen fugacities of terrestrial petrogenesis, iron enters the pyroxene structure both as Fe3+ and Fe2+ whereas in lunar and most basaltic meteorite pyroxenes, iron is Fe2+ only. Inspection of this large number of high quality pyroxene analyses demonstrates that these phases carry a signature of the planetary body in which they evolved.