THE true phase relations of Mg-rich pyroxenes 1–3 are obscure partly because most measurements were made on cooled specimens which underwent a crystallographic transformation on cooling.

Figure 2: Comparison of the average compositions of Shergotty pigeonite and augite cores with experimental pyroxenes. To produce a melt saturated with two pyroxenes on its liquidus at lower water ...

Pyroxenes are a major group of rock-forming minerals. Scientists investigated the iron ion status of a calcium-rich pyroxene, using Mössbauer spectroscopy on thin sections of single crystals.