Formula: Cu₂(AsO₄)(OH)

Species: Arsenates

Colour: Olive green to yellow or brown, gray-green, grayish white; light green in transmitted light.

Lustre: Sub-Adamantine, Sub-Vitreous, Resinous, Silky, Pearly

Hardness: 3

Specific Gravity: 4.46

Crystal System: Monoclinic. Olivenite crystals are shortto long prismatic, acicular or tabular. Other habits are globular, fibrous, reniform. Massive, granular and earthy.

Member of: Olivenite Group, Adamite-Olivenite Series. Libethenite-Olivenite Series.

Name: Originally named arseniksaures kupfererz by Martin Klaproth in 1786 in reference to the chemical composition. Named olivenerz by Abraham G. Werner in 1789 in allusion to its olive-green color. Robert Jameson changed the ending “erz” to “ite” in 1920.

Type Locality: Carharrack Mine, Gwennap, Cornwall, England, UK

Olivenite is copper arsenate hydroxide that is thought to form a solid-solution series with Libethenite,  a copper Phosphate hydroxide. The copper analogue of Adamite. May be confused with Zincolivenite which is a chemically and structurally distinct species with a defined ratio of Zn:Cu. A relatively common, thermodynamically very stable secondary copper mineral found in the oxidized zones of copper deposits containing arsenic-bearing phases, especially Tennantite, Enargite and others.