This amazingly sculptural Keweenaw Peninsula copper specimen has a HUGE, 7.0 cm, elongated tetrahexahedral copper crystal and overall, a very nice, rich patina. Undoubtedly old material. Ex Seaman Museum Collection. The label on the specimen bottom is DM 1864. The DM prefix on the catalog number does not stand for Dean Martalock collection, but instead was created by Jean Kemp in the 1970s, and stand for "display mineral."