When do you ever see a TRULY fine thumbnail, complete, with such quality from the old Illinois fluorite mines? Seldom - because, few miners collected thumbnails, and the fluorite was sold by the pound for most of its mining history there while the mines were active, and even into the 2000s after they shut down. Why would people save thumbnails? It was very rare. However, this was self collected by a thumbnail collector who went underground in this mine, in 1993. For overall balance, color, and symmetry, I think it is really quite exceptional for this material in a thumbnail size, and even competitive for a fluorite in any thumbnail case. Glassy and gemmy, this color zoned fluorite crystal has an amber core with a light purple rim.