Fluorite on sphalerite – WL Davis-Deardorff mine, Cave-in-Rock, Illinois, USA
 The W.L. Davis-Deardorff Mine was one of, if not the, most important producers of fluorite specimens in the famous fluorite district of southern Illinois during the first half of the 20th century. According to economic mineralogist Allen V. Heyl, the Deardorff Mine was the model mine from the 1930s to the 1950s. It closed in the early 1960s.
 Fine fluorite specimens from this mine are often associated with crystallized sphalerite and are highly sought after today. At first glance, this highly aesthetic display specimen is reminiscent of finds from the Elmwood Mine, Tennessee.
 The deep violet fluorites have a slightly yellowish core, which becomes more or less intense depending on the incidence of light.
 The fluorites, with edge lengths of up to 2.9 cm, sit aesthetically on a crystalline, shiny sphalerite matrix.