Silica aerogel belongs to the oxide-based engineering ceramics classification, while optical silicon belongs to the non-glass optical ceramics. There are 12 material properties with values for both materials. Properties with values for just one material (11, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is silica aerogel and the bottom bar is optical silicon.