Three previously unknown minerals have been discovered encrusted in the walls of abandoned uranium mines in south Utah.
The three minerals are formed by the interaction of uranium ore with oxygen. They are named and described in a paper published in Mineralogical Magazine. The minerals were discovered by a mineralogy student at Michigan Technological University, Travis Olds, who has since moved to Notre Dame University.
The mines in Utah where the minerals were found have been abandoned for years, but were heavily mined during the Cold War.
The mineral leesite is bright yellow with blade-like crystals up to 1mm long arranged in stacks. It was found in the Jomac Mine. It is a member of the schoepite mineral family; miners called the general mess of these minerals growing on the tunnel floors "gummites."
Leószilárdite was named after the Hungarian physicist Leo Szilard, who first came up with the idea of the nuclear chain reaction in 1933. After the discovery of nuclear fission in 1938, Szilard proposed that uranium would be the best element for a chain reaction process.
It was discovered in the Markey Mine in Utah's Red Canyon. It is a carbonate mineral with bladed crystals of a slightly paler yellow colour, and can partly dissolve in water.
"If you look at leószilárdite in a picture, you can kind of pick out that [the crystals] have an unusual shape," Olds said in a statement. "But put them under the scanning electron microscope and it's obvious."
The mineral redcanyonite, found in the Blue Lizard Mine, also in the Red Canyon, is also a striking yellow colour. It is structurally similar to the uranium mineral zippeite, also found in old uranium mines. Redcanyonite is the rarest of the finds, and can only form where there is manganese as well as rock rich in organic material.
"The only way to better understand the chemistry of uranium is to go out and find new minerals, and describe their topology and structures," Olds said. "They teach us a lot about how uranium can then be moved in the environment."