Fascinating specimen consisting of a huge roughly cubic sphalerite crystal almost completely covered in epitaxial chalcopyrite crystals. The chalcopyrite is partly iridescent and gives a "shimmering" effect when viewed from different angles. Has a small patch of buff colored dolomite crystals on cherty limestone matrix at the base. An old piece from the Joplin District in Missouri. Measures 7 x 8 x 6 inches (17.8 x 20.3 x 15.2 cm). Weighs 16 pounds. No damage.