This is a significant, and surprisingly large, crystal of Chondrodite from the old Tilly Foster Mine. According to Mindat.org: Large iron ore (magnetite) deposit discovered in 1810. The mine was 600 feet deep in 1879. Mining ceased in 1897, after 13 miners were killed in a rockslide. Specimens today are obviously hard to come by, and I know people who are dedicated to collecting Tilly material. This crystal is 2.7 cm long, and has excellent deep color and luster for its size. The left termination is complete, though there is some contacting and a small break at the right edge, where it may once have been doubly-terminated. Still, large and significant for the locality. very OLD classic, Ex. Dan Ehrling Collection (Milwaukee, WI), acquired in a trade with the University of Chicago in the late 1960s and early 1970s in exchange for his African material.