The present article presents data on the content of uranium, thorium, potassium in the geological formations of southwestern Priargunya and attempts to classify rocks according to their radioactive properties (based on the results of 670 luminescent, 290 radiochemical, 160 chemical analyses performed in the laboratories of VSEGEI and other organizations, and many thousands of field gamma measurements). The relative error in determining the content of radioactive elements by repeated analyses does not exceed 25%.