I think its some kind of copper alloy but it doesn't have green patina, but old larg cents found in this area are in great condition and most of the time dont have green patina. It weights only 1.86 grams
Cool ring. Did a Google Image search and came up with several similar (but not identical) looking rings with a rider on a horse rearing up that date from the 1930s-50s. Certainly not a definite ID, just a way forward.