These malachite 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 azurite and malachite. They are secondary copper carbonates containing the elements Cu, C, H and O. Mining started in several copper oxide zones within the mine where the carbonate minerals were found. This specimen consists of malachite replacements or pseudomorphs of azurite crystals with some minor matrix attached. This piece measures 2 1/8 x 1 3/4 x 1 inches or 53 x 45 x 25 mm.