Mineral Specimen #1581 Fluorite
Cave-In-Rock, Hardin County, Illinois
This Fluorite is a light purple with small blotches of much darker Purple. Closer examination reveals these areas of darker coloration are centered around small Chalcopyrite crystals. Most of these Chalcopyrite crystals are on the surface of the specimen with a few deeper within the Fluorite. Many of the Chalcopyrite crystals are decomposed and some are now missing. Exactly why the Fluorite took on a deeper color around the Chalcopyrite is unclear. The specimen is in fairly good condition with only very small cleavages on some of the corners. However, the pictures are a bit misleading in that there is a very thin coating of a white material on parts of the specimen which does not show up in the photos. This is either Quartz or possibly Barite (definitely not Calcite - it did not react to HCl when I tried to etch it off). If for display purposes, one were to apply either mineral oil or WD40, this white material would virtually disappear.
From the Reed Meyers collection
9.3 x 7.7 x 4 cm
This mineral is also found in the following galleries: Minerals From the United States | Fluorite | Minerals Priced Between 25 and 49 Dollars