Fluorite from the Illinois-Kentucky Fluorspar District, Cave-In-Rock, Illinois
Cluster of large, light purple, stepped, fluorite cubes, from the historic Illinois-Kentucky Fluorspar District, Cave-In-Rock, Hardin County, Illinois. The fluorite contains numerous small hydrocarbon inclusions which are fluorescent under UV. Under short wave the fluorite fluoresces light blue and the hydrocarbon inclusions white. The fluorite responds with deeper purple/blue fluorescence under long wave, again with the hydrocarbon inclusions showing a white response. The size of this specimen is 67 x 61 x 56 mm, and it weighs 182 grams.