The two minerals are often found together and are essentially indistiguishable by ordinary methods. Meteoric oxygenated waters dissolve the uranium from primary uranium minerals and the uranium is later deposited in reducing enviroments more favorable to the formation of carnotite. Since many deposits in sandstones are associated with petrified trees and other fossils, it is reasonable to assume that the decaying material helped produce the required reducing enviroment. Carnotite is an uncommon and interesting uranium mineral that can coat host rocks with an attractive yellow powder. Remember, this is also a radioactive mineral and should be stored away from other minerals that are affected by radioactivity and human exposure should always be limited.
Color is bright yellow.
Luster is pearly to dull or earthy. Crystals are translucent to opaque. Cleavage is perfect in one direction. Fracture is uneven. Hardness is 2.