These brochantite 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. Over thirty-six mineral species have been identified at the mine including extremely large world class brochantite crystals like these. Brochantite is a copper sulfate that contains the elements Cu, S, O and H. This piece consists of a quartz matrix that is partially covered with sprays and clusters of brochantite crystals ranging from silken fibers to prismatic crystals. It measures 3 1/2 x 2 3/8 x 1 inches or 88 x 60 x 25 mm as displayed in photo 1.