A cluster of deep purple semi lustrous cubic fluorite crystals hosting small crystals of calcite. In good condition.The Southern Illinois Fluorspar District, located primarily in Hardin and Pope counties along the Illinois-Kentucky fluorspar district border, is a historic mining region that became the premier domestic source of fluorite, barite, and lead in the United States. Geologically, the deposits formed along fault zones and fracture systems within Mississippian-aged limestone and sandstone strata, where warm hydrothermal fluids deposited concentrated veins and replacement bodies. Mining activity began in the early 19th century, around the 1830s and 1840s, and expanded dramatically during the 20th century to supply crucial flux for the domestic steel and chemical industries. Although large-scale commercial production eventually ceased in the late 20th century due to foreign competition and environmental regulations, the district remains world-famous among mineral collectors for producing magnificent fluorite specimens, often accompanied by well-crystallized calcite, barite, and sphalerite.
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