100 Pesos Guanajuato - Gold and Silver Proof Issue

The Guanajuato issue belongs to Mexico's long-running series of state-themed bimetallic commemoratives, each pairing a gold centre with a fine silver ring — a format the Casa de Moneda developed in the early 2000s that briefly made Mexico the most technically ambitious mint in the Western Hemisphere for proof bimetallic production. Guanajuato's selection was straightforward: the state's silver and gold mines, active since the colonial period, made it the dominant source of precious metal for the Spanish Crown for over two centuries, at points accounting for roughly a third of global silver output.