This is a flat disc of metal bored at one end. It would function as a drop pendant, possibly it was originally a coin, although there is no detail left on the surface now.
From Egypt, Giza, debris above mastaba G 7637. 1925: excavated by the Harvard University–Museum of Fine Arts Expedition; assigned to the MFA in the division of finds by the government of Egypt.
Harvard University—Boston Museum of Fine Arts Expedition