Fluorite on Calcite

Unknown Owner

A lovely light purple color zoned and gemmy semi lustrous cubic fluorite crystal measuring 1.0 cm on edge perched on a grouping of scalenohedral calcite crystals. From the early to mid 1970s or earlier, in good condition.The Gaskin Mine, situated in the Illinois-Kentucky Fluorspar District in Pope County, Illinois, was a notable producer of fluorite, lead, and zinc. Geologically, it exploited a series of vein-type deposits hosted within Mississippian-aged sedimentary rocks, specifically the St. Genevieve and St. Louis limestones. The mineralization occurred along steeply dipping normal faults where hydrothermal fluids deposited fluorite, galena, and sphalerite, often accompanied by calcite and barite. Historically, mining activity in this part of the district began in the early 20th century, with the Gaskin Mine itself seeing significant development and production primarily during the 1940s and 1950s. It was operated by various entities, including the Minerva Oil Company, until the decline of the domestic fluorspar industry led to its closure. Today, the site remains a significant historical reference point for the structural geology and mineral paragenesis of the southern Illinois mining region.