Geography of Illinois before the dinosaurs. Galena, a lead ore, has been mined in the northwest corner of the state. The ore was processed around Peru, Illinois, where river transport was available to bring the ore to a source of coal. About six tons of coal are needed for each ton of ore. Fluorite, calcium fluoride, is the state mineral. It is mined in the southeastern portion of the state, around Metropolis. Fluorine gas is produced from fluorite. This is used in the production of uranium hexafluoride in Metropolis, Illinois for use at the gaseous diffusion plant in Paducah, Kentucky. Geodes can be
Galena, Illinois top-ten "Charming Small Towns". Galena is located at (42.418171, −90.431472) along the Galena River, which is one of many tributaries of the Mississippi River. According to the 2010 census, Galena has a total area of , of which (or 99.83%) is land and (or 0.17%) is water. Galena is located in the Driftless Zone, an area that was not covered by glaciers during the recent ice ages. This area, which includes the far northwestern corner of Illinois, escaped glaciation, while almost the entire state was glaciated, nearly to its southern tip. Because it escaped glaciation, this area is known for