Arsendescloizite - Encyclopedia

    Class : Phosphates, arsenates, vanadates
    Subclass : Anhydrous arsenates
    Crystal System : Orthorhombic
    Chemistry : PbZn(AsO4)(OH)
    Rarity : Rare to very rare

Arsendescloizite is an arsenate of lead and zinc. It is a rare secondary mineral from the superficial oxidation zone of polymetallic hydrothermal deposits where it is associated in particular with willemite, goethite and mimetite. Its name comes from its chemical composition : arsenic plus descloizite. It forms small tabular crystals of 1 mm maximum, assembled in rosettes or nipples, pale yellow to pale green.

Main photo : Arsendescloizite from Ojuela Mine, Mapimi, Durango, Mexico © Rob Lavinsky

Arsendescoizite in the World

Arsendescloizite is best known as small aggregates encrusting tennantite and chalcocite at Tsumeb (Namibia). It is also reported in Mapimi (Mexico), and in Toroku (Japan). In Europe it is present in the Michael mine, near Lahr, in the Black Forest (Germany).
Photo : Arsendescloizite from Tsumeb Mine, Namibia © Paul de Bondt

Arsendescloizite in France

This mineral is not known in the French underground.

Twinning and special crystallizations

No known twin for this mineral species

Fakes and treatments

No fake or treatments identified for this mineral species.

Hardness : 4
Density : 6.57
Fracture : Irregular
Trace : White

TP : Translucent to transparent
RI : 1.990 to 2.035
Birefringence : 0.045
Optical character : Biaxial -
Pleochroism : Not visible
Fluorescence : None

Solubility : -

Magnetism : None
Radioactivity : None