Trace amounts of uraninite occur in the lower levels of two silver-base-metal producers in the Coeur d'Alene district, Idaho. For the most part, the uranium-bearing veinlets follow small structures in the quartzite wall rock of the major ore bodies. The radioactive veinlets are bordered by a zone of red stained quartzite.The ores are characterized by tetrahedrite, pyrite, arsenopyrite, and chalcopyrite in a siderite-quartz gangue. Uraninite forms small spherulites that replace vein quartz, quartzite wall rock, and (to a lesser extent) tetrahedrite. Observations to date suggest that uraninite was deposited in the late stages of ore deposition.Ore deposits of the Coeur d'Alene district have certain features in common with the great pitchblende producing veins of the world.