10 Pesos Sonora - Silver Proof Issue

The Sonora issue belongs to México's long-running "Estados de la República Mexicana" series, which systematically commemorated each of the country's 31 states plus the Federal District across roughly a decade of annual releases. Banco de México contracted the production of these proof strikes to exceptionally tight tolerances, with the .999 fine silver specification representing a step above the .925 standard used in many of the series' earlier companion issues.

Sonora's selection for a 2004 release placed it among the mid-series entries, by which point collector demand had established a healthy secondary market — particularly in the southwestern United States, where the state's cross-border cultural presence drove acquisition beyond purely numismatic circles.