Fluorite

Unknown Owner

Glassy deep purple mostly gemmy cubic crystals of fluorite to 1.5 cm in size covering both sides of matrix. Micro-chipping is present but very minimal, overall in good condition. The Southern Illinois Fluorspar District, primarily encompassing Hardin and Pope counties, was historically the most productive fluorspar-mining region in the United States. Geologically, the district is situated within the Illinois-Kentucky Fluorspar District, where mineralization occurs as vein deposits along faults and as bedded replacement deposits within Mississippian-aged limestone, particularly the Ste. Genevieve and St. Louis formations. These Mississippi Valley-Type (MVT) deposits are world-renowned for producing spectacular, multi-colored cubic fluorite crystals, often associated with galena, sphalerite, and calcite. Historically, mining and quarrying began in the early 1800s for lead, but shifted to fluorspar in the 1870s to meet the demands of the steel and chemical industries. Production reached its zenith during the mid-20th century, with the district providing a critical strategic supply for the World Wars. Economic pressures and foreign competition led to a steady decline in activity, culminating in the closure of the last major operation, the Hastie Quarry and the associated Ozark-Mahoning mines, in the mid-1990s.