Exoplanet Mineralogy

This chapter begins with some basic concepts regarding the structure and mineralogy of rocky planets, how to read and construct ternary diagrams, and why partial melting occurs when plate tectonics is operative. Partial melting is a key concept in that it governs crust and core formation, which in turn control mineralogy. These sections are for astronomers, or geologists new to the study of igneous petrology. From there, computational approaches for estimating planetary mineral assemblages will be introduced. These quantitative methods are simple, consonant with the level of information currently available on exoplanet compositions, and while largely intended for mineralogists, should be accessible to non-specialists as well. Such methods are followed by a study of error when plotting mineral abundances in ternary diagrams, for mineralogists and petrologists who construct such diagrams. The chapter concludes with caveats, and the ways in which exoplanets might surprise us.