Mineral Species: Clinoclase

Chemical Formula: Cu3AsO4(OH)3

Chemical Name: Copper Arsenate Hydroxide

Mineral Class: Arsenate

Mineral Notes: Clinoclase is a rare secondary copper mineral. It was first discovered at Wheal Gorland Mine (Cornwall), a producer of many rare secondary minerals. Clinoclase has a striking dark blue to dark green-blue colour. Although usually small, its acicular crystals make for very attractive specimens.

Description: A rich specimen consisting of two forms of Clinoclase. The pale-blue form is mostly amorphous and has an earthy luster. Scattered around the top of the specimen are clusters of the other, highly crystalline form. These crystals have a glassy apperance and the characteristic deep blue-green colour.

Location: Majuba Mine, Pershing Co., Nevada, USA.