Hydrothermal polymetallic vein system at the far southern end of the "bolivian tin belt". Principal veins are the Chocaya, Oploca, San Miguel, San Pedro, and Potosi veins, emplaced in Ordovician shales and sandstones of the Acoyte Formation. Ore-bearing solutions related to late Miocene dacitic intrusives. Mine closed around 2000.
Note: "OTTEMANITE" specimens on the market from here are actually the new species SUREDAITE.