Libethenite - Encyclopedia

Libethenite crystals from Portugal

    Class : Phosphates, arsenates, vanadates
    Subclass : Anhydrous phosphates
    Crystal system : Orthorhombic
    Chemistry : Cu2PO4(OH)
    Rarity : Rare


Libethenite (or chinoite) is a relatively rare secondary phosphate in the oxidation zone of copper deposits, where it mixes with malachite, pseudomalachite and brochandite. Its transformation into chrysocolla was observed. Phosphorus is partially replaced by arsenic, giving rise to a very limited solid solution with olivenite, to which it is very similar. It owes its name to its locality of discovery : Libethen in Slovakia. Libethenite occurs in short prismatic crystals or is slightly elongated in [100], sometimes in regular pseudo-octahedra when the vertical prism and horizontal prism forms have comparable development. It has a vitreous to oily luster and a typical olive-green to blackish-green color. It is a mineral only reserved for the collection, but little known collectors.

Libethenite in the World

The most beautiful crystals are 35 mm green-black pseudo-octahedra from the Kitwe-Nkana mines in Zambia's copperbelt. The deposits of Congolese Katanga (Kakanda and Likasi) also provided good centimetric crystals. Respectable crystals rarely reaching a centimeter and implanted on quartz are reported at Lubietova (ex-Libethen, Slovakia) and very rare centimetric crystals were extracted from the English Cornwall deposits (Calstock, Redruth, Wheal Phoenix). Finally, it is common in the copper deposits of northern Chile (Chuquicamata, Mercedes).

Libethenite in France

In the French underground, libethenite is only present in millimeter-sized crystals. It is reported in the silver mine of Zimmerbach (Haut-Rhin), Montebras (Creuse), Falgayrolles and Bastit (Aveyron) and finally Valcroze (Gard). The photo on the left shows a sample photographed by Jean Claude Dol in prismatic crystals.

Twinning

No twin known for the species.

Fakes and scams

No fake inventories for this mineral species.



Hardness : 4
Density : 3.7
Fracture : Irregular to conchoidal
Trace : Green



TP : Translucent to transparent
RI : 1.701 to 1.790
Birefringence : 0,080
Optical character : Biaxial -
Pleochroism : Weak
Fluorescence : None


Solubility : Acids and ammonia

Magnetism : None
Radioactivity : None