The Davis Deardorff locality was once hailed as one of the largest specimen producing localities in Illinois. Why haven’t you heard of it? It closed in the 60s. 
A vast majority of the specimens from the locality were broken or mislabeled over the years, and the localities popularity diminished with the lack of serious fluorite collectors and the towering popularity of locales like Minerva and Denton mine. It also didn’t help that people were largely labeling specimens more simplistic things like “cave-in-rock” or “Mahoning Mine”, as they didn’t understand the values of locality specificity at the time.Now unfortunately it has become very challenging to discern a lot of the pockets from the locale. If you don’t have a rather extreme degree of knowledge of the finds, or a good provenance label, most of them float around with vague or inaccurate locality info. Although, notably still, most of them were damaged or discarded. 
12.6 x 8.2 x 3.9 cm.