By style, the pieces are almost certainly 1715 Fleet. Both Mexico, the first one shown dates 1701-1712; second piece 1712-14 (enough on the shields to determine that). Both would appear to be 1 Real denomination based on the relative dimension of what's visible (looks like the first is a bit more seaworn, plus was a more compact planchet as made).
By the way, note that the half-real denomination (of ANY mint) used the MONOGRAM design, not the shield or pillars/waves...
I see nothing about the porosity to suggest that these aren't genuine low-grade Fleet finds. Rather than nice center-clump finds, probably loose pieces, rather moderately eaten at/sea-washed, that were then fully blasted/stripped. We're seeing spots where the salt water adhesions ate into the surfaces and then once stripped away, those pores and half-eaten surfaces, mushy from seawear and cleaning, are left behind. This is why for numismatic purposes, you shouldn't go SUPER heavy on the cleaning because what's underneath the crud is often not pretty (though in some cases, it wouldn't matter much either way). Not really of "numismatic" quality, these pieces often end up in jewelry like we have here, headed for tourist sucker shops along the cruise circuit, etc. (and of course, in the Fisher shop also) to be sold at a very healthy markup over the bullion value of the bezel plus the low value of the coin.
The bezels look like (solid) 14K that typically ends up on these... of course that is to be in confirmed in hand.
The following are actually not from the 1715 Fleet, but the Joanna wreck off South Africa... this lot came to mind to give an idea of how such material presents (that wreck was notorious for most of it's finds being rather sea-worn and then overcleaned/stripped bare):
https://auctions.stacksbowers.com/lots/view/1-1K5LH
A few more extreme examples, actually from the 1715 Fleet:
https://www.ebay.com/itm/Mexico-Sil...-Coin-w-Mel-Fisher-Cobb-Coin-COA/202191320329
https://www.ebay.com/itm/1715-Fleet-Shipwreck-Recovered-Mexico-Silver-Cob-1-2-Real-/391957408861
PS - On the matter(s) of fakes and such that have been (half) discussed... the notable court case (ca. 1997) was in regards to purported ca. 1730 Mexico 2 Escudos pieces that were sold as 1733 Fleet finds. In reality, these were shown to be outright modern fakes. Yes, some metallurgical testing was done, but frankly would not have been necessary to people who knew their Mexican gold well, as the style was not quite correct for the period. Of course, true coin people were not the primary market for those...
INTERNATIONAL BUSINESS; Hunter Admits Sale of Fake Gold Coins - The New York Times
There was also the question (from back in the early 1970s) of some purported 1733 Fleet milled Mexico pillar 8 Reales. These were rare 1732 and 1733, the first two dates of the style... oddly including several mintmark/assayer combinations which were previously unknown (and have not been observed since). These were a subject of rather intense scrutiny at the time... some almost made it to public sale (several appear in the Schulman Sept. 1973 auction catalog, though were apparently pulled before the sale). It appears that over time, these were generally discredited and disappeared off the scene. You occasionally see a piece of this style surface on eBay, often coming from sources (or heirs of such) that make sense as having had access to them.
coincommunity.com/forum/topic.asp?TOPIC_ID=151633
colonialcobs.com/forum/index.php?topic=125.0
colonialcobs.com/forum/index.php?topic=98.0
That's not really what we're looking at in the case of these pieces.
