It looks to be a 2 reales that somebody cut to a square shape to make a medallion out of it. This is a Pillar dollar -
It is a 2 reales from Guatemala. The date is anywhere from 1733 to 1753, but the final numbers are off the flan. It has not been cut but was made in that shape, except for the hole. It was produced in the years that the Guatemala mint had the proper pillar dies but not the milled planchets, thus they stamped the new dies on the old cob style flans. They began striking the round milled planchets like what Doug shows in 1754, except of course that his example is from Mexico City.
