Pseudoboleite Locality: Amelia Mine, Santa Rosalía (El Boleo) , Boleo District, Municipio de Mulegé , Baja California Sur , Mexico ( Locality at mindat.org ) Size: 5.3 x 4.6 x 3.3 cm. Pseudoboleite is much rarer than boleite from the Amelia Mine at Boleo, Mexico. This fine piece features two, lustrous, indigo-blue pseudoboleite cubes to 7 mm aesthetically set on stabilized clay matrix. Actually, the pseudoboleite is the 3-dimensional outgrowth upon boleite, a cube of which remains underneath the pseudoboleite accretion. Ex. Bill Larson Collection. Bill and Ed Swoboda spearheaded a mid 1970s mining project at the Amelia Mine. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Pseudoboleite
Pseudoboleite is an IMA-recognized mineral species in the halide class, with the chemical formula Pb₃₁Cu₂₄Cl₆₂(OH)₄₈.
It crystallizes in the tetragonal crystal system (space group I4/mmm).
Key properties: Mohs hardness 2.5; specific gravity 4.85; Pearly on cleavages luster; optically uniaxial.
IMA symbol Pbol, IMA status: approved, named in 1895.
A secondary mineral formed through reaction of chloride with primary sulfides in the oxidized zone of Pb–Cu deposits; in smelter slag immersed in and leached by sea water.
It is found associated with Boleite, cumengeite, atacamite, anglesite, cerussite, phosgenite, gypsum (Boleo, Mexico).
Its name comes from the Greek for false and boleite, as it was mistaken for that species.