Comparison between the turnover pressure-grain size relations used by Bürger et al. (2024) (dashed and dash-dotted lines) and the main result of this work (Eq. (20), solid line). In addition to the data obtained for SiO₂, the turnover pressure inferred from the Al₂O₃ samples are illustrated as well but were not used for fitting. It should be noted that we only used transition widths in the range ∆ = 0.4...0.6 for all data points analysed using Method A.