Can't really tell whether there's a through-hole in the back of the "shank" feature ... but the piece generally looks like what one would call a "medallion" decoration. Looks way to heavily made to be a button. Maybe a decorative feature on an inkstand lid, or a box or something like that.
I would guess maybe 1870-1895. as this form of decoration was popular on items in the Victorian era.
I'm using an AT Pro. My yard isn't very big but it is productive. Last count over 150 coins most clad but a large cent, some silvers, a buffalo, Indian head, and lots of wheats.