Diaboleite is a rare lead, copper chloride, and is one of the great treasures from the renowned Mammoth-St. Anthony Mine at Tiger. The Diaboleite is an intense azure blue and the better-developed crystals have a tabular habit. However, that is not the valuable part of this historic mineral specimen: Rather, the plentiful, small red microcrystals make this one of the world's best of species. This piece is legendary micro collector, Neal Yedlin's, Yedlinite! This is a very fine thumbnail containing very good microcrystals on a relatively large specimen. It is in his original box, which says, in his own hand " Diaboleite + Red Unknown (new) " on the front. On the bottom, he noted that he got this at Schortmans's in August of 1968. The specimen was later given in exchange to Wil Henderson, and I bought his micro collection recently. This was the major piece in the collection, as far as I am concerned. This specimen is notable for its richness for the species, and its historical association as well.