This is a large thick cylindrical ring that may be an earring or hair ring. It is made out of gold-plated copper in which the copper has corroded so badly that the gold-plating has burst off in places.
From Egypt, Sheikh Farag SF 203 . 1913: 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