Hey there, I found this coin at a yard sale that looks like its Spanish and was wondering if the markings are of any significance (and if it would be worth anything). Thanks for the help!
The ? - 8 - M on the top row gives the mint mark (I cannot make it out from the picture), the denomination (8 escudos), and the assayer initial. The middle row, P - P - A, is an abbreviation for The proof of the coin. The bottom row, just above the waves, gives the date as 1712. Coins with pillars and waves were supposedly produced only in Peru.
As far as the front goes, it's a Jerusalem Cross with "DP" and what looks like birds or very worn lions, which I cannot find anything on those marks. The lions make perfect sense, but the "DP" is a unknown to me. There would normally be a bust of the king on front or the cross with castles and lions. Almost all gold cobs have a Jerusalem cross on one side. The cross has prominent foils around it or a circle of dots. Sometimes castles and lions appear in the angles of the cross, but not always.
Around the cross are the assayers marks, and other assorted info spending on the year struck. Your best bet is to get it professionally appraised, esp with the large number of fake or "commemorative coins" around.
This one seems similar: https://commons.wikimedia.org/wiki/File:8_escudos_Lima_1710.jpg
