Cave-in-Rock Sub District, Illinois-Kentucky Fluorspar District, Hardin Co., Illinois, USA.
Two crystals in one, a dark fluorite crystal inside the corner part of a large cubic crystal. This is great example of secondary growth. The fluorite is bright light purple-bluish sprinkled all over the surface with tiny sparkling chalcopyrite crystals, no matrix and a good specimen, from Ian Strachan collection
