Thumb rings have been in use in Asia since the Neolithic period. The first examples were likely made of leather, but artifacts made entirely of leather do not last thousands of years. Surviving artifact rings are made of bone, horn, or stone; presumably most would have incorporated a leather guard. Comparison with historical and modern rings shows little functional change over the millennia. In the cemetery of the small Rui state at Liangdaicun near Hancheng on the Yellow River (where it flows south between the provinces of Shaanxi and Shanxi), a Lord of Rui was interred in a tomb, M 27, dated to the eighth century BCE. His grave goods included two thumb rings, made of gold but of an entirely modern pattern.