Cordoba, Argentina, 4 reales, 1851, small sunface. Janson-61.1.4; KM-24.3. 12.63 grams. AU- with only light high-point wear, clean fields with areas of faint hairlines, some interesting over-punches in the die (like denomination 4/4 and date 51/51), rims slightly crude (as made).
Estimate: $125-200