Rocky planet densities vs. host star [Mg/Fe] for planets hosted by both FGK (circles) and M dwarfs (triangles), colored by planet radii values. Rocky solar system bodies (Moon, Mercury, Venus, Earth, and Mars) are plotted for comparison as orange diamonds. Our best-fit linear model from our MCMC fitting routine is plotted as a blue line along with the associated 1σ confidence intervals. Pearson correlation statistics are provided in the bottom left corner, considering just the FGK-hosted rocky planets and the entire FGKM sample. We label the high-confidence and possible thick disk planets TOI-561 b and Kepler-10 b, respectively.