Mg/Si ratios of JWST-observed hot Jupiter host stars vs. separation (semimajor axis). Mg/Si ratios compiled from J. M. Brewer et al. (2016) with an error of 3.3% as quoted in J. M. Brewer & D. A. Fischer (2016) as well as N. Hejazi et al. (2023). Diamond markers indicate systems in which the hot Jupiter companion is reported to have spectral signatures of SiO₂(s) clouds. Square markers indicate no current robust detection for a particular silicate species. The purple dashed line indicates the Mg/Si ratio point that distinguishes the onset of either forsterite (>0.9) or quartz (<0.9) condensates (E. Calamari et al. 2024). The navy dashed line indicates the theoretical gas-phase Mg/Si ratio in a solar-type disk from A. Thiabaud et al. (2015).