LIROCONITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated arsenates
    Crystal system : Monoclinic
    Chemistry : Cu2Al(AsO4)(OH)4 4H2O
    Rarity : Very rare


Liroconite is a very rare hydrated arsenate, typical of the oxidation zone of copper deposits. Its name comes from the Greek leiros (pale) and konis (dust), in reference to the color of its streak, light blue or light green. Liroconite forms flattened to lenticular crystals, reminiscent of packed octahedra. The color is pale blue to deep blue, rarely green to verdigris.

Main photo : Liroconite from Wheal Gorland, St Day, Cornwall, England, UK © Jeff Scovil

Liroconite from Wheal Gorland, St Day, Cornwall, England, UK © Rob Lavinsky
Liroconite from Wheal Gorland, St Day, Cornwall, England, UK © Stephan Wolfsried
Liroconite from Xianghualing Mine, Chenzhou, Hunan, China © Uwe Haubenreisser
Liroconite from Xianghualing Mine, Chenzhou, Hunan, China © Hercule Shen

Liroconite in the World

Although very rare in distribution, liroconite has been found in abundance in the gossan of the Wheal Gorland and Wheal Unity mines, near Gwennap (English Cornwall). It was there that the largest known crystals of this mineral (more than 3 cm) were discovered on a bed of chrysocolla. Other Cornish copper mines (Redruth, Saint-Just, Gunnislake...) also provided crystals but of lower quality. Elsewhere in the world, liroconite is very rare and only forms microscopic crystals in the oxidation zone of copper deposits : Bisbee (Arizona), Spania Dolina (Slovakia), Schwarzenberg (Saxony, Germany).

Liroconite in France

In France, liroconite is known in microcrystals at Cap Garonne (Var).

Twinning

No twin known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.



Hardness : 2 to 2.5
Density : 2.94 to 3.01
Fracture : Irregular to conchoidal
Streak : Pale blue to pale green


TP : Translucent to transparent
RI : 1.612 to 1.675
Birefringence : 0.063
Optical character : Biaxial -
Pleochroism : None
Fluorescence : None


Solubility : Acids

Magnetism : NoneRadioactivity : None