These mimetite crystals are from the San Antonio Mine, East Camp, Santa Eulalia Mining District, Mun.de Aquiles Serdan, Chihuahua, Mexico. This district encompasses a large area that contains over a dozen mines. Mining activities are primarily for the extraction of silver and other metals. There a over 120 different types of minerals found at this mine including mimetite. It is an arsenate that contains the elements Pb, As, O and Cl. This specimen is a 360 % mound-like formation of cauliflower shaped clusters of mimetite crystals. There are some druse calcite crystals near the base of the formation. This piece measures 1 3/4 x 1 5/16 x 1 1/4 inches or 45 x 33 x 32 mm.