  Graphite, a model (semi)metal with trigonally warped bands, is investigated
with magneto-absorption experiment and viewed as an electronic system in the
vicinity of the Lifshitz transition. A characteristic pattern of up to twenty
cyclotron resonance harmonics has been observed. This large number of
resonances, their relative strengths and characteristic shapes trace the
universal properties of the electronic states near a separatrix in the momentum
space. Quantum-mechanical perturbative methods with respect to the trigonal
warping term hardly describe the data which are, on the other hand, fairly well
reproduced within a quasi-classical approach and conventional band structure
model. Trigonal symmetry is preserved in graphite in contrast to a similar
system, bilayer graphene.
