Planets and the stars they orbit are born from the same primordial cloud of gas and dust, and the primordial compositions of rocky exoplanets should have iron and refractory abundance ratios consistent with their host star. While we observe that Venus, Earth, Mars, and smaller bodies such as carbonaceous chondrites have solar abundance ratios of iron to magnesium (Fe/Mg), Mercury is enriched in Fe/Mg while the Moon is depleted, indicating that planet formation processes such as giant impacts and magnetic interaction have the ability to alter primordial rocky compositions. To test the extent to which rocky exoplanets have primordial compositions, we measure the masses of 19 super-Earth sized (1-1.7R?) planets around stars with known metallic abundances. For 5 stars in our catalog we use new precision RVs from Gemini/MAROON-X and Keck/HIRES, and homogeneously re-analyze literature RVs for the full sample using updated stellar properties. We model their interior compositions to measure Fe/Mg in the planet using bulk density and assuming a rocky composition. We observe a correlation between planetary and stellar Fe/Mg, but not with a 1-1 correspondence. Instead, the planets have a significantly wider range of Fe/Mg values than their host stars with a slope of 4.5, which indicates the prevalence of formation mechanisms that diversify planetary compositions and in particular suggests that planets more often become enriched in iron rather than depleted.