Antlerite from Chuquicamata, Chile.
Antlerite is a green mineral consisting of basic copper sulfate (Cu3[OH]4SO4). A minor copper ore of widespread occurrence, it is formed by oxidation of primary copper minerals. It is named for the Antler mine, Arizona, where the first specimens were collected.
Anterlite crystallizes in the orthorhombic system in crystals up to 2 centimeters long. They commonly appear fibrous and in cross-fiber veinlets, feltlike, granular or powdery lumps and aggregates.
It is found in association wit brochantite, atacamite, chalcanthite, kröhnkite, natrochalcite, linarite, and gypsum. Deposits occur in Arizon, New Mexico, California, Nevada, and Alaska, USA; Chihuahua, Mexico; various locations in Chile; near Zwickau, Saxony, Germany; Caldbeck Fells, Cumbria, and at several mines in Cornwall, England; and Lerida, Spain.