Elongated crystals of copper, to 2 cm in length, have formed a shapely fan-like or dendritic specimen. The copper crystals have been imbued by dark red patina of cuprite. Very appealing! This is a classic and very old locale: http://www.Mindat.org/loc-3845.html states that "An underground copper mine consisting of 14 shafts located south of Houghton. The Ohio and Isle Royal Company was organized in 1852 to explore the island of Isle Royale in Lake Superior. The same year, the company transferred all operations to south of Houghton where three rich veins of copper were discovered. Five shafts were sank in the area of prehistoric pits that also followed the veins. Much copper was found as several masses were discovered very close to the surface. In 1855, the company was reorganized into the Isle Royal Copper Company but closed just two years later in 1857. After this time, the mine was leased on tribute to the Mabbs Brothers. In 1862 the company bought the Webster Mining Company after which time the company worked the mine between 1863 and 1870, but closed it again. Again, the Mabbs Brothers worked the mine on tribute for several years. Between 1853 and 1885, the mine produced 8.8 million pounds of copper. In 1899, the reorganized once again into the Isle Royal Copper Company, Inc. This new company was a merger of the old Isle Royal, Huron, Grand Portage, Fure, and Dodge Mines. With the additional mines, the