I have this 1821-1947 50 pesos coin. It says it's 37.5 grams of pure gold and on the back it states Estados Unidos mexicanos. I have a second coin as well and I'm not quite sure if it's authentic. It's an 1854 20 dollar Baldwin coin and it has been scratched on the surface as shown in the picture.
The 2nd Coin, the Baldwin Coin is fake. No such thing The 1st Coin looks interesting but don't put your fingers on the surface so much!
If the first coin is genuine - it's hard to tell from the picture - then it's a Mexican 50 Pesos Libertad made of 1.2 ounces of gold. You can do the math on the value assuming authenticity. Get it authenticated and, if it checks out, put it in a safe container in a safe place.
Nobody likes Alec Baldwin.........most especially, a particular person (who shall remain nameless), who resides in a big white house..........