This is a significant, and surprisingly attractive, specimen of clinochlore 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. Usually, you get chondrodite, and a few other species like clinochlore as mere associations. However, here it is definitely the dominant species, in a really nice, 3.2 x 2.5 x 0.6 cm, freestanding, crystal. It is easy to see the metallic green color. In fact, I cannot recall a clinochlore of this size, as showy, from any other locale? very OLD classic, Ex. Dennis Mullane Collection