I see diamond in the database, but not graphite. The optical properties of graphite from 0.12-40eV (in plane) and 2-40eV (normal) can be found here: http://link.aip.org/link/doi/10.1063/1.369370. Given the intense interest in graphene and other forms of highly ordered graphite, I think this would be a good addition to the database.
By the way, this is an excellent database and highly appreciated!