Andorite with Pyrite

specimen number:
2262063

location:
San Jose Mine, Oruro, Bolivia

description:
Lustrous metallic striated crystals of andorite measuring to 2.3 cm in length across the top of a crystallized pyrite matrix. Some damage is present as seen, the prominent crystal grouping is in good condition.

The San Jose Mine, located near the city of Oruro in the Oruro Department of Bolivia, is a renowned hydrothermal vein deposit situated within the Altai-type tin-silver belt of the Eastern Cordillera. Geologically, the mine consists of a complex system of veins hosted in a dacitic volcanic dome of Miocene age, where mineralizing fluids deposited a diverse array of sulfosalts and sulfides. The locality is the type locality for andorite, which occurs as distinct, steel-gray to black prismatic crystals that are often deeply striated and occasionally found in aesthetic clusters. Historically, mining and quarrying at San Jose date back to the colonial era, but modern industrial operations became significant in the late 19th and early 20th centuries, with the Corporacion Minera de Bolivia (COMIBOL) overseeing much of the production until the mid-1980s. Despite various periods of closure and restructuring due to economic fluctuations, the mine has seen continued activity through mining cooperatives into 2026. Today, it remains a globally significant site for mineralogists and collectors, particularly for its world-class specimens of rare silver-lead-antimony sulfosalts.

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