Charles III Mexico Coin ??

Another donation to Oxfam in Exeter. As always, your help is very much appreciated.

I think this is Mexico rather than Spain, but I could be wrong, but I can't find one that matches the design, diameter and weight.

Diameter 39 mm approx.

Weight 16.5 approx.

https://en.numista.com/catalogue/index.php?r=CAROLUS+III+1776&st=147-150-149&cat=y&im1=&im2=&ru=&ie=&ca=3&no=&v=8+Reales&a=&dg=&i=&b=&m=&f=&t=&t2=&w=&mt=&u=&g=&c=&wi=&sw= 

 Probably one of those but with F M lettering looks like Mexico. 

Bolivia = J R / P R

Chile = D A

Guatemala = G P / NG P / NG M

Mexico = F M / M F / F F

Peru = J M / M J / M I

Spain = MPJ / SCF / MM / SC

 for around 1776 date anyway. 

The problem is the weight isn't right, even thought he diameter is:

Peru: Weight 27.07 g

I've checked ours on two different scales and they both are around 15/16 g.

So maybe it's a fake?

Hello

This coin “wants” to be a Mexico 8 Reales FM 1776 coin.

But the weight of only 16,5 gr speaks clear facts: far to little regarding the normal weight of 27 gr !  And it is difficult to think that tear and wear (or even saltwater - in case of treasure-coin) produces such a loss of mass.

Here a picture of a nice 1773 FM piece, also from Mexico  ("Aureo & Calicó" Catalog)

So, I would plea for “guilty because fake” .

Regrads

Disappointing, but thanks for your help. We wouldn't wnat to sell fake coins in Oxfam.

Not hard, if you know what and where to search. 

  on left México mintmark; on center “8R”, face value 8 Reales; on right “F • M •”, assayer's initials: Francisco Arance y Cobos - Mariano Rodríguez Puerta.

In fact, it is from Spain, since at the date all Hispan-American region were Spanish colonies, later after revolution movements, during 19th. Century they became on independant countries. That is why coin shows portrait of Carlos III (Carolus III or Charles the 3rd.).

Now, 8 Reales were 1 Peso Fuerte, that weighed 27.07g of silver .903 (or .902 or .901, depending on the mint.). If  your coin weighs 16.5g, then is obvious is not an original one. Sincerely, the pictures don't show color, surface and bright of silver… 

Thanks for all this detail. Its really interesting