History · Geology
About Boleo District (Santa Rosalía)
The Boleo district at Santa Rosalía in Baja California Sur (northwest Mexico) is the world’s only locality for the rare blue Cu-Pb-Ag chloride boleite, along with its closely related epitaxial overgrowth species cumengeite and pseudoboleite.
Geology
The deposit is a sediment-hosted Cu-Mn-Co system in Pliocene marine sediments. Halite-rich groundwaters interacted with Cu-bearing fluids to produce the unusual chloride mineral suite.
Notable Minerals
Boleite (deep-blue pseudocubic crystals), pseudoboleite, cumengeite (epitaxial pyramidal overgrowths on boleite), atacamite, paratacamite, chalcocite. Most material was extracted historically; supply is essentially unrenewable.
Collector Notes
Sharp boleite cubes from Boleo are among the rarest and most coveted secondary copper minerals — small thumbnails command four-figure prices. Cumengeite-on-boleite pieces are extraordinary structural curiosities.
Minerals Produced Here
- Atacamite (氯铜矿)
- Boleite (碱铜铅矿)
- Chalcocite (辉铜矿)
