Boleite - Encyclopedia

    Class : Halogenides
    Subclass : Oxychlorides
    Crystal system : Cubic
    Chemistry : Pb26Ag10Cu24Cl62(OH)48 . 3H2O
    Rarity : Very rare


Boleite is a rare secondary mineral from copper deposits, typical of arid climates in a chlorinated environment (closed basins, evaporite lagoons, and marine littoral). The boleite owes its name to its locality of discovery : the Amelia Mine in Boléo in Mexico. It presents itself in cubic crystals generally of a few millimeters of edge, more rarely pseudo-cubic, pseudo-dodecahedral (photo of left) and pseudo-octahedral of a magnificent dark blue hue. It frequently constitutes aggregates comprising intergrowths with pseudoboleite and cumengeite. It is a very rare mineral, crystals over 1 cm are extremely sought after by mineral collectors.

Boleite in the World

The most beautiful boleite crystals are perfect cubes of 2 cm edge. They all come from Amelia Mine, El Boleo District, Mexico  the large Broken Hill Australian deposit also provided superb 5mm crystals, as did the Mammoth Saint Anthony mine (Arizona, USA). Boleite is also found in micro-crystals in the slag discharged into the sea from the lead-silver-copper mines of Lavrion (Greece).

Boleite in France

In France, boleite is reported in microcrystals in the foundry residues of the Huelgoat lead mine in Finistère (Brittany).

Twinning and special crystallizations

No twinning report for this mineral species but some cubes may have an epitaxy (oriented overgrowth) of cumengetite, and pseudo-octahedra of cumengetite appear on the 6 sides of the cubes of boleites to form a complex set (draws below).

Fakes and scams

Some cubes could be glued on their powdery matrix....



Hardness : 3 to 3.5
Density : 5.054
Fracture : Irregular
Trace : Blue-green




TP : Translucent
IR : 2.05
Birefringence : 0
Optical character : None
Pleochroism : None
Fluorescence : None


Solubility : Nitric acid

Magnetism : None
Radioactivity : None