A sample of subbituminous uraniferous coal from the Red Desert, Sweetwater County, Wyo., has been studied mineralogically. The coal contains gypsum, kaolinite, quartz, calcite, and limonite. This suite of minerals and the absence of pyrite show that the uranium is associated with the organic constituents of the coal. The minerals that have been isolated contains 0.0006 percent uranium, a content that is to be expected for nonuraniferous sedimentary rocks. The organic components of the coal contain approximately 0.002 percent uranium. On the basis of material-balance calculations, the organic components carry 98 percent of the uranium in the coal.