The following characteristic features of the mineralogy of uraniun are discussed in the article: 1) all known uranium and uranium-bearing minerals contain oxygen; 2) uranium in minerals is present only in the tetra- and hexavalent states; 3) the bulk of the uranium in the earth's crust is concentrated in nonuranium minerals in the form of isomorphous replacement of other elements (thorium, zirconium, rare-earth elements, etc.); 4) the conditions under which uranium and uranium-bearing minerals are formed differ; 5) radioactivity is one of the most characteristic properties of uranium minerals.