Anhydrous arsenate containing hydroxyl, olivenite group, forms a series with libethenite and with adamite.
Specific gravity: 3.9 to 4.5
Streak: Olive-green to brown
Colour: Olive green to yellow or brown, grey-green, greyish white; light green in transmitted light.
Solubility: Soluble in acids and in ammonia
Common impurities: Fe,P
Olivenite is a relatively common, thermodynamically very stable,
mineral found in the oxidised zones
of copper deposits containing arsenic-bearing phases, especially
tennantite and enargite
(Mindat). It is the most common secondary copper arsenate in
the oxdised zone of hydrothermal copper
Associated minerals include clinoclase, conichalcite, tyrolite, cornetite, cornwallite, metazeunerite, scorodite, pharmacosiderite, spangolite, chalcophyllite, brochantite, malachite, azurite and chrysocolla (HOM).
At the Block 14 open cut, Broken Hill, New South Wales, Australia, olivenite occurs with beudantite-segnitite, bayldonite, mawbyite and mimetite. Later sulphate minerals such as brochantite and linarite also occur on some specimens (AJM 3.1.54).
At the New Cobar deposit, New South Wales, Australia, olivenite occurs in vugs in quartz, associated with chenevixite and agardite, and almost always associated with partially oxidised arsenopyrite (AJM 11.2.80).
At the Desolation prospect, Mount Isa Block, Queensland, Australia, olivenite is found on chrysocolla, associated with clinoclase. Olivenite and libethenite also occur on earlier chrysocolla and As-rich pseudomalachite crusts (AJM 17.2.86).
At the Bali Lo prospect, Ashburton Downs, Western Australia, olivenite occurs intergrown with chenevixite (AJM 13.1.34-35).
At the Telfer gold mine, Western Australia, olivenite has been found radiating from cavity surfaces in quartz veins overgrown by chrysocolla (AJM 12.1.39).
At the Clara mine, Near Wolfach in the Black Forest, Germany, olivenite and its associated minerals agardite-(Ce), cornwallite and clinoclase, are perched on a fluorite and/or baryte matrix with disseminated tetrahedrite-tennantite. Also an olivenite-adamite solid solution is found associated with philipsburgite (R&M 90.1.45).
At Ightem, Bou Azzer, Morocco, zinc-rich olivenite occurs associated with powellite (MinRec 38.5.385).
At Tamdrost-West, Bou Azzer, Morocco, cobalt and nickel-rich olivenite has been found in cavities in quartz associated with pharmacosiderite (MinRec 38.5.385).
At Tsumeb, Namibia, olivenite occurs with azurite and malachite (R&M 93.6.546), and also with adamite, zincolivenite, duftite/conichalcite and arsentsumebite, often on quartz (R&M 95.3.210-232).
At Caldbeck Fells, Cumbria, England, UK, olivenite is rare. At Carrock mine and at Ingray Gill it occurs in cavities in quartz. At Dry Gill mine it has been found with beudantite, and at Old Potts mine it has been found with cornwallite and conichalcite (C&S).
At the San Rafael mine, Nye county, Nevada, USA, olivenite occurs within zones containing mixite and conichalcite in the rosasite stope. Olivenite has also been documented here in association with cornubite and cornwallite (R&M 85.6.520).
At the Majuba mine, Pershing county, Nevada, USA, olivenite is associated with cornetite (Dana).
At the Mammoth mines, Tintic district, Utah, USA, olivenite is associated with clinoclase, tyrolite and conichalcite (Dana).
euchroite (s) to olivenite (s) and H2O (l)
Cu2AsO4(OH). 3H2O ⇌ Cu2AsO4(OH) + 3H2O
The Activity-pH diagram below was calculated at 298.2 K for the main Cu2+ and Pb2+ arsenate minerals. Boundaries are calculated for constant activities (roughly equivalent to concentrations) of Pb2+ and Cl- ions in solution, over a range of values of pH and of Cu2+ activity. Higher chloride activites make the stability fields of bayldonite and duftite vanish, with respect to the encroachment of that of mimetite (LMW p269).
The arsenate mineral formulae are:
The Activity-pH diagram below was calculated at 298.2 K for some carbonates and copper arsenates for constant activity (roughly equivalent to concentration) of H2AsO4- in solution, over a range of values of pH and of H2CO3 activity (MM 52.687).
The mineral formulae are:
The Activity-pH diagram below was calculated at 298.2 K for some arsenates and sulphates for constant activity (roughly equivalent to concentration) of H2AsO4- in solution, over a range of values of pH and of SO42- activity (MM 52.689).
The mineral formulae are:
Back to Minerals