Bismuthinite, Cassiterite

An exceptionally unusual specimen from the legendary Siglo Veinte Mine, featuring a bright, silvery metallic bismuthinite associated with cassiterite. Small but distinct cassiterite crystals are visible on one side of the specimen, confirming the mixed association noted on the original label. The piece comes from the international collection of Peter Tarassoff and is labeled “Bismuthinite in cassiterite,” reflecting its uncommon mineralogical character. Among decades of Bolivian material on the market, this appears to be a unique or possibly single-discovery association, with no closely comparable examples currently known.

The Siglo Veinte (“Twentieth Century”) Mine, located just southwest of Llallagua, began major production in 1901 and became one of the world’s most important tin mines under the ownership of Simón Iturri Patiño, the famed “King of Tin.” Following nationalization in 1952, the mine became a central component of Bolivia’s state mining industry and played a major role in the country’s social and political history. Although small-scale cooperative mining continues today, classic specimens from earlier periods are increasingly scarce. This piece represents a rare and distinctive survivor from one of Bolivia’s most historically and mineralogically significant mining centres.