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 Historic District Places. The Galena Historic District contains more than 1,000 buildings constructed before 1900 that are considered contributing properties. The center of downtown Galena is laid out in three parallel segmental tiers starting at Main Street closest to the river. Beyond Main Street, and at a higher elevation, are Bench and Prospect Streets. Main Street forms the primary commercial strip through Galena and is lined with buildings two, three, and four stories tall. Most of Main Street's structures are built of red brick and cast in Federal style of the simple commercial style of the 1840s. On Bench Street, most of