Dynamic microwave conductivity of graphene-based shungite

The conductivity of thin graphene-based shungite sheets has been experimentally investigated. Direct-current measurements have been performed upon reflection of microwaves. It is shown that, at a low carbon content, the dynamic conductivity of shungite is similar to its static conductivity and, at a high carbon content, exceeds the latter by more than an order of magnitude. The data obtained are interpreted using shungite structural components.