Predicted planet mass fractions of core-forming elements Fe and Ni, mantle molar Mg/Si ratio, and mantle minor element (all elements aside from Fe, Mg, Si, and O) molar fraction, as a function of host stellar C/O. Compositions are calculated based on stellar abundances from the GALAH catalogue by applying disk composition-dependent depletion factors to each element. Earth composition is shown (yellow diamond) from Wang et al. (2018), and solar C/O = 0.54 (Asplund et al. 2009); further, the two systems shown in Fig. 7 are indicated (black squares).