First time posting on here. We recently started digging an old hacienda in Mexico. This is what we found the first days. Found a Spanish reale and some of the crust fell off to be able to read a date. Also found an old plate that we broke while digging.
Congrats on your find. It appears to be a Mexican 2R piece. If so, the diameter should be 28 mm and the weight about 6.7 grams.
That series was minted from 1747 through 1757; the assayer's initial is "M" --which appears after the date.
Don.....