These cuprite crystals are from the Milpillas Mine in Cuitaca, Mun de Santa Cruz, Sonora, Mexico. Mining at this locale began in 2006 with the extraction of copper minerals. Thirty-six mineral species have been identified at the mine including cuprite. It is a secondary mineral found in oxidized copper ore bodies and it contains the elements Cu, C and O. Mining started in several copper oxide zones where outstanding secondary copper mineral specimens were recovered. This specimen consists of an exposed cuprite vein filled whose center contains several intact crystals up to 4 mm wide. Their luster is mirror like. This piece measures 1 9/16 x 1 1/4 x 3/4 inches 39 x 32 x 19 mm.