AURICHALCITE

    Class : Carbonates, Nitrates, Borates
    Subclass : Anhydrous carbonates
    Crystal System : Monoclinic
    Chemistry : (Zn,Cu)5(CO3)2(OH)6
    Rarity : Uncommon

Aurichalcite is a secondary carbonate produced in hot climates, in the oxidation zones of copper and zinc deposits. Crystallographically, it is the copper equivalent of hydrozincite. Its name comes from the Latin aurichalcum (yellow copper) and the Greek orikhalcos (copper ore). It comes in fine flattened and striated crystals, most often acicular, assembled in delicate tufts, feather dusters or fragile fibrous encrustations on a matrix of limonite ; it is more rarely columnar, grainy, botryoidal or scaly. Under its most characteristic facies it is translucent, has a silky to pearly luster, and a magnificent pale green to greenish blue, sky blue or turquoise blue color. The crystals hardly reach the centimeter.

Main photo: Aurichalcite from Rohdenhaus Quarry, Germany © Harjo Neutkens

Aurichalcite from Kelly Mine, New Mexico, USA © Rob Lavinsky
Aurichalcite and calcite from Ojuela Mine, Mapimi, Mexico © Rob Lavinsky
Aurichalcite from Barbara Mine, Laurion, Greece © Fritz Schriber
Aurichalcite from Chah Kuh, Esfahan, Iran © Meinrad Kempf

Aurichalcite in the World

There are very beautiful samples of aurichalcite at Kamareza (Lavrium, Greece), at Mapimi (Mexico) where it can be associated with rosasite, hemimorphite or even be found in inclusions of calcite rhombohedra which gives them a superb color blue. Aurichalcite is also present in Tsumeb (Namibia), in Bisbee and in neighboring deposits in Arizona (USA). The largest known crystals (several centimeters) come from the Iranian mine of Chah Kuh, near Esfahan. In Europe, besides Kamareza, aurichalcite is known in Monteponi and Sulcis in Sardinia (Italy), in Matlock and Leahills (Great Britain).

Aurichalcite in France

In France, aurichalcite is reported in Chessy (Rhône), in Can Pey (Pyrenees), in L'Aiguille du Gouter (Haute-Savoie), in Crozet (Loire), in Argentolle (Saône-et-Loire), at Steinbach (Haut-Rhin), at the Couloumier Mine (Ariège), at Cayrolle and at the Tistoulet mine (Aude), at St-Laurent-le-Minier (Gard), at Cuzac (Lot) and in many other localities.

Right photo : Aurichalcite from the St-Nicolas Mine, Steinbach, Haut-Rhin, France © Philippe Cayé

Twinning and special crystallizations

No twin known for this mineral species.

Fakes and treatments

No fake or treatment identified for this mineral species.


Hardness : 1 to 2
Density : 3.96
Fracture : Irregular
Trace : Light blue


TP : Transparent
RI : 1.655 to 1.744
Birefringence : 0.089
Optical character : Biaxial -
Pleochroism : Low
Fluorescence : None

Solubility : Acids, ammonia

Magnetism : None
Radioactivity : None

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