Black Diamond (1977)

Iván Berend is a nobleman from the countryside, owner of considerable wealth. If necessary, he duels and plays cards like his fellow gentry, if necessary, he dances and compliments like most cavaliers. But far from him is this high life. He prefers to lecture on natural history, and does not hesitate to prove his claims by burning a diamond. He runs the Bondavar mine and experiments on a fire extinguishing agent. Evila, the beautiful starlet, and her impetuous fiancé, Peter Szaffrán, work in the mine. They are hired by the Viennese banker Félix Kaulmann to help him with his grand plan for the coal basin, which will ruin Ivan Berend.