Stone Ring, Western Sahara, Africa. 4.25" (10.8 cm) diameter, 1" (2.5 cm) thick at center, 7" (18 cm) inner circumference, 315 grams Neolithic Period, 2000 b.p. or earlier No one really knows how these rings were used; some speculate that they are armbands; others, burial goods. It has one tiny chip on the edge at 3 o'clock as seen in the primary photo above.