Boleite - Encyclopedia

    Class : Halides
    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.

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

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).

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