EUCHROITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated arsenates
    Crystal system : Orthorhombic
    Chemistry : Cu2(AsO4)(OH) 3H2O
    Rarity : Very rare

Euchroite is a very rare copper arsenate, sometimes existing in the oxidation zone of arsenic copper deposits. It is also present in neofrmation in slags. Its name comes from the Greek eukhroia (beautiful color). Its crystals are short to isometric prismatic, sometimes thick tabular, of a beautiful emerald green color.

Main photo : Euchroite from Ľubietová, Banská Bystrica, Slovakia © Jordi Fabre

Euchroite from Ľubietová, Banská Bystrica, Slovakia © Juraj Demian
Euchroite from Copper Cliff Mine, Missoula County, Montana, USA © Michael Cline
Euchroite from Ľubietová, Banská Bystrica, Slovakia © Martin Stevco
Euchroite from Ľubietová, Banská Bystrica, Slovakia © Rob Lavinsky

Euchroite in the World

Euchroite was only abundant in the Slovakian copper mine of L'ubietova, near Banska Bytrica, where it occurred in frequent millimetric crystals (15 mm for the largest) in the cracks of a limonite schist and psilomelane. Euchroite is also known in beautiful crystals in the slag of the Laurion mines (Greece), in Montana (USA) and in Zapachitsa (Bulgaria).

Euchroite in France

In France, euchroite was reported in Chessy (Rhône).

Twinning

No twin known for this mineral species.

Fakes and treatments

No fake listed for this mineral species.


Hardness : 3.5 to 4
Density : 3.44
Fracture : Irregular to sub-conchoidal
Streak : Green

TP : Translucent to transparent
RI : 1.695 to 1.733
Birefringence : 0.038
Optical character : Biaxial +
Pleochroism : Low
Fluorescence : None

Solubility : Acids


Magnetism : None
Radioactivity : None