A perfect gem crystal of calcite, water clear, almost totally clean inside, from the famous mid-1800s to late-1800s era of discovery of fine calcites in England's midcountry iron district. This is a precision crystal, so sharp and clean on the edges, it looks machined. Few thumbnails of this material were ever recovered, sold, and then surviving till today. In fact, this is almost certainly a trim off a larger specimen in the Harvard Museum, as it came from Phil Scalisi (who handled so many of the Harvard deaccessions over the years). One likes to think he went to great lengths to find the perfect gem calcite thumbnail for his good friend, Ernie, searching the historic large pieces in the museum to pop one off cleanly! Scalisi to Schlichter, to Flynn.