Rosiclare and the Illinois fluorspar

Fluorite is the Illinois state mineral, and Hardin County was the fluorspar capital of the United States for a century. The Rosiclare and Cave-in-Rock veins produced cubes of purple, blue and yellow fluorite that sit in museums worldwide. Commercial mining ended in the 1990s. The old dumps and the surviving pay-to-dig operations still yield display-grade crystals, which makes this one of the genuinely great rockhounding destinations east of the Mississippi.