Anisotropy of graphite optical conductivity

The graphite conductivity is evaluated for frequencies between $0.1$ eV, the energy of the order of the electron-hole overlap, and $1.5$ eV, the electron nearest hopping energy. The in-plane conductivity per single atomic sheet is close to the universal graphene conductivity $e^2/4\hbar$ and, however, contains a singularity conditioned by peculiarities of the electron dispersion. The conductivity is less in the $c-$direction by the factor of the order of $0.01$ governed by electron hopping in this direction.