Uranium Minerals
Three uranium-containing minerals, [tyuyamunite] (pronounced tyew-yuh-moon-ite), possibly [carnotite], and [metatorbernite], have been found in Missouri but none has been mined commercially. Tyuyamunite and carnotite are canary yellow powdery minerals so similar in appearance they can be differentiated only by chemical and x-ray properties. Both minerals contain uranium, vanadium, oxygen, water, and one other element, which, if it is calcium, the mineral is tyuyamunite, but if it is potassium the mineral is carnotite. The canary yellow color referred to is distinctly different from the brownish or reddish yellow color of iron oxide minerals. These yellow uranium minerals have been found near Ste. Genevieve along cracks in limestone and in the black shale above the limestone, and in dark, sandy shales near Shelbina, and elsewhere north of the Missouri River.
Black shales (high in organic matter) of marine origin are the most highly radioactive, whereas black shales deposited on land (as with coal), and all shales of other colors are usually lower in radioactivity.
Metatorbernite is a soft, pale apple-green scaly mineral that has been found in paper-thin cracks in flint fire clay deposits. It contains uranium, copper, phosphorus, oxygen, and water. All of these uranium minerals activate a Geiger counter.