Cyclotron resonance and Faraday rotation in graphite

The optical conductivity of graphite in quantizing magnetic fields is analytically evaluated for frequencies in the range of 10--300 meV, where the electron relaxation processes can be neglected and the low-energy excitations at the ``Dirac lines'' are more essential. The conductivity peaks are explained in terms of the electron transitions in graphite. Conductivity calculated per one graphite layer tends, on average, to the universal conductivity of graphene. The (semi)metal-insulator transformation is possible under doping in high magnetic fields.