Cuprite - Encyclopedia

    Class : Oxides and hydroxides
    Subclass : Oxides
    Crystal system : Cubic
    Chemistry : Cu2O
    Rarity : Uncommon


Cuprite is a relatively uncommon oxide in the surface areas of copper deposits, where it generally coexists with native copper as well as other oxidized copper minerals such as malachite, azurite or chrysocolla. It was first described by the Austrian mineralogist, geologist and physicist Wilhelm Karl Ritter von Haidinger in 1845. Its name comes from the Latin cuprum (copper). The cuprite is blood red and translucent in small crystals while the larger crystals are often opaque, dark red to metallic black. Malachite pseudomorphs are common, azurite pseudomorphs are rarer. Generally massive and earthy, the developed crystals are rare, the most widespread form is the octahedron, but it can also crystallize in dodecahedra or cubes, note that there is an acicular variety by elongation according to [001] that we call "chalcotrichite". Cuprite is locally an important industrial mineral. It can also be cut in cabochon for jewelry, but its low hardness makes it useless.

Red cuprite from Mashamba West Mine, Democratic Republic of Congo
Malachite pseudomorph after cuprite on azurite from Chessy, France
2,42 ct gemmy faceted cuprite from Congo
Cuprite on native copper from Poteryaevskoe Mine Russia

Cuprite in the World

Among the world's best crystals are the magnificent octahedra of over 10 cm in size from Onganja (Namibia) and to a lesser extent from Tsumeb. Splendid octahedra of 15 to 30 mm have also been found in Cornwall (Redruth, Linkinhorne), Likasi (Katanga, Democratic Republic of Congo) and Copper Queen in Bisbee (Arizona, USA). During the 2000s, beautiful bright acicular red chalcotrichite crystals were found in Daye Co, Hubei Province, China (photo on the right).

Cuprite in France

In France, the Chessy copper deposit in the Rhône department is worldwide known for its magnificent octahedra and dodecahedra of malachite pseudomorph after cuprite, which can sometimes exceed 3 cm in size.

Many other French localities have produced micro-crystals like : Le Moulinal (picture on left), Le Crozet (Loire), Les Mas Dieu (Gard), Villecun (Hérault), Laguépie, Le Burc, Montroc (Tarn), Cap Garonne (Var), etc...

Twinning and special crystallisations

Penetration twins are common.

Malachite pseudomorphs are common (photo on left), cuprite crystals can also be replaced more rarely by azurite, these transformations come from a carbonation that follows the oxidation of Cu+ ions in Cu2+. Native copper pseudomorphs after cuprite crystals has been discovered, but also cuprite epitaxies on native copper crystals.

Fakes and treatments

No fakes known.



Hardness : 3.5 to 4
Density : 5.8 to 6.1
Fracture : Irregular to conchoidal
Trace : Red to brown




TP : Transparent to opaque
RI : Not measurable
Birefringence :  0
Optical character : None
Pleochroism : None
Fluorescence : None


Solubility : All acids or bases
Magnetism : None
Radioactivity : None