Si K-edge of dust samples 1–14 (see Table 1). The x-axis shows the energy in Å and the y-axis shows the amount of absorption indicated by the cross section (in Mb per Si atom). The samples are shown in different panels for easier comparison. Top left panel: difference between amorphous and crystalline pyroxenes (samples 2, 3, 5, and 6). Top right panel: difference between amorphous and crystalline enstatite (samples 4 and 10), including an amorphous pyroxene. Bottom left panel: olivine dust samples. Bottom right panel: our three quartz samples.