Dust emission simulated using the modified blackbody law (see Eq. (6)) for 10 K interstellar grains. The solid lines are calculated using the experimental 10 K opacity of the amorphous E (MgSiO₃) sample (black line) and the amorphous F1 (Mg_2.3SiO₄) sample (grey line). The dust emission assuming a single spectral index of β = 2.0 (dotted line), β = 3.4 (dotted-dashed line) and β = 1.1 (dashed) are also represented. The curves have been normalized at 600 μm.