I've been metal detecting around my 1789 millworkers cottage and mill ruins in Rhode Island. Found a lot of stuff which has been identified, but not this thing. Looks too big to be a suspender buckle and it has what appear to be rivets.
I noticed that this was your very first post on TN - so, Welcome Aboard stonemillmodels! Take a look at Sub-Forums: Rhode Island for information (i.e., clubs, etc.) directly related to your state.