Actually, after looking at the buckle in the pic with the penny in it, I'm sure it's too small to be a hairpiece or sash buckle. I do think a ribbon ran through it and it acted as a buckle of sorts, maybe just for decoration, maybe for a doll or shoes.
May have had a cameo or semi-precious stone (maybe just colored glass "stone") in it?
Seeing the back might help determine what it was meant to accomodate.
I have an original tin type of my great grandfather, and it's tiny, and would fit in that locket. I'm sure the size indicates that was all he could afford, the picture is in an album of other family photos, and he had joined the army, OVI, but in the photo you can't tell. Also a larger photo of a great Uncle, who was a 1st Lieutenant, and had a little more money. Just my swag though. Perhaps today I can search out that tintype and post it here.