Cuba, 50 centavos, long-and-thin key incuse countermark (1872-77) on a Guanajuato, Mexico, 50 centavos, 1872 S, PCGS XF40. KM-R5.1. Nearly full countermark just above center of eagle side of host, which displays a splashy deep red-gold toning all over.
Estimate: 400 - 600 USD