Lower and upper limits (α^ll and α^ul = α^ll + Δα) of the linear absorption coefficient for forsterite (upper panels) and enstatite (lower panels) in the three polarization directions: a-polarization (left), b-polarization (middle), and c-polarization (right). The data resulting from sample F[100] and EB[xx0] are plotted as squares, F[010] and EK[010] as solid lines, F[001] and EB[001] as circles, EK[100] as plus symbols. Lower limits are plotted in color, upper limits with Δα according to Table 1 are plotted in gray. Spectra calculated for 100 K forsterite with reduced Δα = 0.1, 0.2, and 0.3 cm⁻¹ are shown as thin black lines, labeled with the Δα values. For clarity, the spectra are only shown for selected temperatures, as indicated in the legends. The dashed and dotted straight lines indicate power laws proportional to 1/λ and 1/λ², respectively. The wavelength scales in the upper and lower panels are not the same.