This copper included calcite crystal is from the Quincy Mine in Hancock, Houghton County, Michigan, USA. Mining at this locale began in the 1840’s and operated off and on until 1968. Calcite was one of the gangue minerals in the mine and many calcite crystals with copper crystal inclusions were recovered. This crystal has a modified rhombic habit. It is translucent and the copper inclusions are visible under bright light. It measures 14 x 13 x 10 mm.