Looks to me like an 8 reales of Felipe V, around 1704 to 1707, from a Spanish mint (i.e. not from a colonial mint).
The piece Mark posted is Mexico, 1712-14 style. It sold via auction the other day on eBay; it appears someone gave him a reasonable guess attribution of 1715 Fleet (which couldn't be stated with certainty, but definitely "most" pieces of these years are from those wrecks - though less so as the years go by and pieces from those years surface from other sources around the globe). What I would say, though... the authenticity is questionable, and I would lean towards a cast of a salvage piece from afar. Edges have the look, not right porosity... And, while the central detail is rather deeply impressed on both sides (though the actual design elements are mushy)... the detail cuts off very abruptly, despite the planchet not appearing to be all that "unlevel", faceted, whatever word you'd like to use (which is typically what causes an area on a cob to go unstruck). That's often a trait of a cast piece. So, wouldn't say definitively, but highly suspect to this experienced eye. ----- Bardolph's piece, while the wrong attribution, is a very nice (wholesome, genuine) piece... a scarce peninsular Philip V cob 8R, Madrid mint. People often confuse those in the opposite direction (i.e., calling Bardolph's type as Mexico) since most Bourbon shield cobs are in fact Mexico 1702-1733.
The OP coin is a cob minted in Mexico City, around 1714-15. The surfaces show typical erosion (corrosion) from emersion in salt water for hundreds of years. It could be from the 1715 fleet, but without documentation this sheer conjecture on my part. As for authenticity, my guess is that the coin is genuine. The surfaces have the appearance of salt water corrosion, and the coin has been typically over cleaned. The cross side has a somewhat concave shape, consistent with hammer striking. Casts are basically flat on both sides. Further, it is not at all for the strike to be uneven; this is a common feature of cobs and Mexico in particular during the period in which this coin was minted. Weight information regarding the OP coin would be useful, although weight loss would be expected. The OP coin's photos could be sent to Dan Sedwick for his opinion. Here's a link: https://www.sedwickcoins.com/contact.htm Dan is something of a guru when it comes to Latin American coinage, including cobs in particular. For comparison of the OP coin's shield, here's an 8 escudos, 1713, assayer J, for comparison. The shield of this coin is a bit earlier, with subtle differences in the shield design, but it is very similar to that of the OP coin. For 1713, the mint mark is oXM. 26.96 grams
"Casts are basically flat on both sides." "They" get the dimensions/waviness of cob planchets on numerous observed examples. Of course plenty of Mex. pieces were very unevenly struck... but the way the detail cuts off on this piece - especially cross side - ehhh. See the Gulfstream Rarities 1715 Fleet casts... Seller listed weight as 22.7g in the listing, which wouldn't be horribly low for a genuine piece with presenting like this, so that doesn't tell us anything.
Thanks for all the input on the cob. I decided to move it along and listed it on eBay for sale. It did about as well as I would have expected given that there was no COA included. Similar pieces with documentation seem to sell for about twice or three times what mine brought.
Those two videos are very interesting and disturbing. I've stayed away from coins with certificates and salvaged coins in general, unless they are rare and in decent condition. Also, I never really liked Mel Fisher. A local coin dealer, many years ago, "invested" in one of his ventures and was rewarded with a highly corroded, over-cleaned Mexico 8 reales, for $1,200 as I recall - a total ripoff. Additionally Fisher cleaned the encrusted coins using electrolysis, where the coins were suspended in water and an electrical current ran through a wire. The result was cleaned coins to the point of being too bright and reflective, almost as if they were brushed, but without the hairlines. I guess that was a relatively cheap way to process a large number of coins at a time, but the results left much to be desired. Getting back to the videos, there was and is some pretty dubious activity going on. The examples shown do show the same "strikes", with varying levels of casting quality. As I mentioned I don't care for certificates, much less framed certificates! The presenter also mentions beveled edges. This might have been done by this now defunct company, along with shaping the flans to make them more individual. Also, apparently the Mexico City Mint also beveled the edges of some of their coins, particularly gold coins, according to Alan K. Craig, who did a study of the 1715 Fleet 8 escudos in the Florida State Collection. This study can be found in the edition of Florida Archeology, Number 4, 1988. He argues that the beveling was applied to the coins after the die striking process was completed. Why this was done is not clear, but there certainly seems to be a pattern of this practice when one looks at a number of these coins. My coin shows beveled edges, particularly on the cross side. This is my only gold cob from this period, as the affordability of these coins, never great, has plummeted as the prices have skyrocketed over the years.
