It clearly claims to be a shipwreck piece, but it's impossible to judge the surfaces from those pics. At any rate, here's correct alignment of the cross side:
IMO, the coats of arms does not match any Spanish coin during the period 1556 through 1724. What I'm looking at the area where the Flanders and Tirol images appear on the Hapsburg shield and where fleurs-de lis appear on the Bourbon shield coins. On the former, the Flanders and Tirol images do not get near the base of the crest on a real coin--though they do on your coin. And on the Bourbon shield, that area would normally have 3 fleurs-de-lis versus what appears on your coin as a vertically bisected image or images--not found on real Bourbon coins between 1702 and 1715. Remember.....IMO.
Don.......
The design is Potosi, right around 1618, maybe 1617 (the distinctive shot and fat Austria bar is especially telltale on that). Clearly an Atocha-era piece...
'realeswatcher', I stand corrected. I do ack. that a coin similar to this one could be as you suggest. On another forum, I note about a year ago you posted a pic of a similar coin to the one on this thread. It appears to be dated 1617 with the assayer's initial 'M'. Juan Munoz (?) was the assayer during the period 1616-1617 at Potosi. I've taken the liberty to transfer your 2012 pic to here.
Thanks for the clarification.
Don.......