I believe this is a 1797 Charles IIII 1/2 Real (1.48g). However I don’t know where it’s from, other than the Spanish Empire. Any help on how to tell is appreciated. Thanks
This is a Mexico issue. The Mo mintmark is worn and indistinct, but the assayers' initials (FM) also give away that this is a Mexico issue.
Here is a reverse from a Carolus lll, maybe it will help you see what the reverse designs look like. It has a little better detail.
Mexico City actually. Mexico the country didn't exist yet. Some of the other Spanish Colonial mints are also complex arrangements of letters. Lima(LME): https://en.numista.com/catalogue/pieces35033.html and some other forms, skulk around Numista... Potosi (Bolivia) (PTS): https://en.numista.com/catalogue/pieces35033.html
Founding of the Mexico City mint (1536-1572): http://numismatics.org/digitallibrary/ark:/53695/nnan128937