very nice find its known as a spanish half reale or in this case mexican as shown from the mint mark the m with the o over it is for mexico city it was the equalivalent to 6 an 1 quarter cents in its day you can tell this by the r which stands for half reale . 1r =1reale 12 an 1half cents .2r=2reale25cents.4r=4reale 50 cents .8r= 8reale is a mill dollar hope this helped