War of 1812 button?
I dug this up in Indiana at about 8" down and it is the size of a penny and the eagle is a separate but attached piece like it's not just one whole piece there is nothing on the back but what looks like 4 points around the edge that it would have attached to something.
I found this about 8" down with my E-Trac in Central,Indiana. I think its silver because it cleaned up nicely because it had to rings up top that rusted to it but cleaned up on the back it has Hong Kong.