Description | Clinoclase, Cu3AsO4(OH)3 (copper arsenate hydroxide), is a rare secondary copper mineral. Clinoclase has a beautiful dark blue to dark greenish blue color. Although usually small, its crusts of acicular crystals make for very attractive specimens as they coat all the nooks and crevices of a fractured host rock. A specimen of clinoclase is a pleasure to own by any serious collector of rare minerals. |