Because my knowledge in this area is very poor, what makes you question if the coin is legitimate? Is it the details of the coin or rarity?
My English is bad so I'll be shorten. This coin has "plata agria" to the right of "VTRAQUE" (I don't know how to say in english), light surface marine corrosion and the edge has all correct. I would like to know what is the grading in the Shelton Scale, please.
I agree the edge looks correct. We are just nervous about these since SO MANY have been faked. I do not see anything obviously saying this one is false. For a grade, I would say AU55 or so, but it may not grade. The light surface corrosion might mean it cannot grade, and instead be in a details slab. This means it WOULD HAVE graded a 55, but it is damaged.
Np. Its a pretty pillar dollar. I do not think any of mine are this high of grade. I would sir suggest you make sure you check its weight, size, all of the things we cannot do by picture. There are some really high quality fakes of these. It looks good from what I can see from a pic, but I could do more with a coin in hand.
The weight is 26'55 gr., considering the corrosion I see right it. As I said I haven't doubt about its authenticity, I only wanted to know your opinions about the grading. PS: I apologize for my bad english.
I'm inclined to agree with brg and question the coin being genuine. I do not think that is corrosion, I think that is the result of it being a cast fake. And some of the fine details are flat out wrong for the coin.
I know what I think about my coin. I want to know is which details you refer. Do not you put it with photos of other coins. Is very easy to say that a coin is a fake but you must to explain how you came that conclusion. "La plata agria" (I say again that I don't know how it say in english) is a irrefutable evidence of authenticity.
la plata agria translates as - sour silver, so I have no idea what that is supposed to mean. But there are no marks or anything to the right of VTRAQUE, or your coin or those I pictured, nor are there supposed to be any marks in that location. As for the differences in details, I have marked them on your coin. You can compare those areas to the other 2 coins I pictured and plainly see the differences. The two things I have circled in red on the obverse of your coin, the only examples where those details occur are on the Mexico 8 reales from 1763. On the reverse of your coin I have circled the detail on the bottom band of the crown. On your coin it is completely different from what it is supposed to be, which is the design you can see on the coins I pictured. This detail is exactly the same on all dates from this period of Mexico coins. Couple those design differences with the appearance of your coin, which looks like cast examples look, and with the light weight of your coin, and you have the reasons I think your coin is a fake. But if you wish to believe it is genuine, by all means do so.
Assuming the coin is authentic, it would likely grade XF details, possibly AU details. Neither of the two large USA grading companies would put this coin in a problem-free holder because it has salt water corrosion.
Not going to comment on authenticity, since pillars are not my forte, but I can clarify what "plata agria" is. This term in Spanish numismatics refers to areas of visible planchet stress marks. This can be often seen on weakly struck coins, or coins struck on planchets of uneven thickness. If you can imagine, when silver bars were rolled out to the right thickness, before planchets were punched out of that sheet, the surface of the metal was covered in stress marks from the pressure that metal experienced during this process. These stress marks were eliminated when the coin was struck except in cases I mentioned above. These stress marks are areas of "plata agria". By the way, I don't see this occurring on the originally posted coin. Some examples: Look at the area on the obverse near the first two digits of the date: Here's another example. Plata agria on the obverse right field: ~Roman.