The Sonora issue belongs to Mexico's long-running series honoring individual states, each pairing a regional subject with bimetallic proof construction combining .999 gold and .999 silver — two metals that defined Sonora's own economic history. The state's northern desert yielded significant silver strikes during the colonial period, and its mines remained active well into the twentieth century.
KM#702 carries a low mintage typical of the proof state series, produced exclusively at the Casa de Moneda in Mexico City rather than any regional facility.
The Sonora issue belongs to Mexico's long-running series honoring individual states, each pairing a regional subject with bimetallic proof construction combining .999 gold and .999 silver — two metals that defined Sonora's own economic history. The state's northern desert yielded significant silver strikes during the colonial period, and its mines remained active well into the twentieth century.
KM#702 carries a low mintage typical of the proof state series, produced exclusively at the Casa de Moneda in Mexico City rather than any regional facility.