This is a ring bezel and part of shank. It has the prenom of the king impressed on the bezel: [nb-mAat-ra] Nebmaatre, Amenhotep III (Dynasty 18).
From Egypt, Giza, E and a little N of mastaba G 7152. 1926: excavated by the Harvard University–Museum of Fine Arts Expedition; assigned to the MFA by the government of Egypt.
Harvard University—Boston Museum of Fine Arts Expedition