Mineralpedia Details for Olivenite

Named after its common appearance as a mineral that is olive-green in color. Most typically olive green, but also brownish green to yellow green. Short prismatic to acicular crystals, also fibrous (variety leucochalcite), to tabular. It is “the most common secondary copper arsenate in the oxidized zone of hydothermal copper deposits.” Most notable localitiies include Majuba Hill, Nevada; Tsumeb; Tintic district, Utah; Cornwall, England. Other localities include France, Germany, Greece, Morocco, Namibia, and Chile among many others. 

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/olivenite.pdf

Formula

Cu₂AsO₄(OH) 

Crystal System

Monoclinic 

Crystal Habit

Acicular to Prismatic, Radial, Fibrous 

Cleavage

Indistinct, Indistinct, Indistinct 

Luster

Vitreous - Greasy 

Color

olive green, yellowish brown, dirty white, blackish green, liver brown 

Streak

yellowish green 

Geological Setting

In oxidized zone of copper and arsenate rich deposits.  

Class

Monoclinic - Prismatic 

Fracture

Brittle - Conchoidal 

Hardness

3 

WebMineral

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Mindat

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Olive green prismatic crystals to 0.5mm in radial sprays throughout matrix.

Dark green blocky Olivenite crystals to about 0.5mm with light green edges.

Olive green acicular crystals to 2mm associated with pastel to darker green somewhat glassy, botryoidal Cornwallite.

Deep green prismatic crystals of Olivenite to 3mm with bright pastel green cuprian Adamite.

Stout emerald green Olivenite crystals, the longest to 8mm but averaging 3mm or so. Associated with bright yellowish green botryoidal Gartrellite.

Deep olive green divergent crystal groups to 8mm. The actual color approaches a deepr, darker green than the photos.

Quartz vugs under 1cm lined with grass green acicular Olivenite.

Dark green aciular crystals of Olivenite.