Lustrous black crystals of Sphalerite are inter grown with crystals of Quartz and Chlorite, from the Wheal Kitty group of mines, St. Agnes, Cornwall. Tetrahedral crystals of Sphalerite measure to 1cm, with white prismatic Quartz crystals, and a granular to massive green Chlorite. Minor amounts of Chalcopyrite and Pyrite are present on the specimen. Crystal specimens of Sphalerite are not commonly seen from the mines. The specimen comes with an old Dr. F. Krantz label dating to the later end of the 19th century.