This faience amulet is of a wedjat eye and has a blue glaze. The wedjat eye represents Horus' left eye lost in battle and later restored magically by Hathor. The eye came to symbolize wholeness.
From Egypt, Giza, St. G 7700. December 1931: 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