F_NIR and F30/F13 for this sample of Herbig disks, highlighting the three classes as in Fig. 1. Following Meeus et al. (2001), we mark disks where the 10 μm silicate emission has been detected (“IIa” and “Ia”) or not (“Ib”); we keep the color-coding for the Ia/Ib labels from Maaskant et al. (2013) to facilitate comparison to that work. Maaskant et al. (2013) showed that silicate emission is tightly related to the F30∕F13 ratio; instead, F_NIR is unrelated (Sect. 4.2).