Autunite
Type of phosphate mineral
- 2 min read
- 3 chapters
Related on Lably
Through Mineral, Crystal and Radioactive decay
Autunite was discovered in 1852 near Autun, France, which is also autunite's namesake. It occurs as an oxidation product of uranium minerals in granite pegmatites and hydrothermal deposits. Associate minerals include metaautunite, torbernite, phosphuranylite, saleeite, uranophane and sabugalite.
Etymology
Autunite was named after the town of Autun, France, where the mineral was initially found. The mineral was named by Henry J. Brooke and William H. Miller in 1854. The archaic name "calco-uranite" pairs with the similarly composed mineral, torbernite, which was named "cupro-uranite". Both minerals are named due to their uranium content, with autunite's name referring to its calcium (calco), and torbernite's copper (cupro) quantity.
Sign in to keep reading
2 more chapters are free with a Lably account.
Locations and mining
Mount Kit Carson, Washington
Researchers found autunite inside the Daybreak Mine on Mount Kit Carson, Spokane, Washington (or sometimes referred to as "near Mount Spokane"), in "vugs, fractures, and shear zones in granitic rock". These areas showed signs of another phosphate, apatite, which may have helped lead to the formation of autunite, by providing a source of phosphate and lime. The formation may have occurred with the interaction of uranium leached from a separate deposit.
90,000 lbs of U3O8 were produced from nine properties, although most of the ore came from the Daybreak Mine.
Other locations
One of the other locations of autunite includes Autun, France, the type locality and namesake of the mineral. The mineral was formed there as an alteration of uraninite and other uranium bearing minerals. Autunite is also found in Cornwall, Saxony, and North and South Dakota.
Meta-autunite
If the mineral dries out, it can lose its water content and convert to meta-autunite-I, which can turn into meta-autunite-II after heating. These two subsequent minerals are very rare in nature. For scientific studies it is recommended to store the mineral in a sealed container to minimize the water loss. Museums are known to have covered the mineral with lacquer to avoid drying of the mineral.