To verify possibilities of the thermic sinking technology the experiments with magmatic rocks (muscovite-biotite granite, amphibole-pyroxene andesite, pyroxene basalt) were made in the preliminary research phase. The contribution presents the microscopic study results of petrographic and structural observations of the rocks after their thermic reworking. Mainly distribution of melted rocks in the form of glass, forming of brittle deformations (fractures) on the level of mineral and rock, and penetration of melt into fissures were observed., Roman Farkašovský and Michal Zacharov., and Obsahuje bibliografii