A Rus or Russian Viking Belt Buckle.  Based on a belt mount.  From an exhibit "Ibn Fadlan's Journey: Volga Route from Baghdad to Bulghar" in a Moscow Museum.  Several other pieces show about 35 mounts on a belt.  Available here

8th - 9th C.  1 1/2" x 1 5/8" 3.8 x 4.1 cm