Clinoclase is a hydrous copper mineral, Cu3AsO4(OH)3. Clinoclase is a rare secondary copper mineral and forms acicular crystals in the fractured weathered zone above copper sulfide deposits. It occurs in vitreous, translucent dark blue to dark greenish blue colored crystals and botryoidal masses. The crystal system is monoclinic 2/m. It has a hardness of 2.5 - 3 and a relative density , olivenite , adamite among others.
Clinoclase was discovered in 1830 in the county of Cornwall New South Wales and associated with copper ore , Montana , and Utah. Also found in France, Austria.
Abichite is another name for clinoclase.
The type locality for clinoclase is the Wheal Gorland in the United Kingdom.