Found at an old farmhouse site; I think I found one of these at the same site before and never got it posted. The back attracts a magnet and shows rust, front looks like brass. If it's real, what era? Thanks!
Argh, no wonder I got deja vu. Found a mate to this a couple years ago and posted it and forgot about it. One reply to the previous thread says the circle of stars above the eagle's head means it is non-military but if i google Great Seal button they all seem to have that. https://metaldetectingforum.com/showthread.php?t=261837