Tusk ring. Warring States-Western Han dynasty  (475 BC-8 AD). Outer diameter 4.0 cm. © National Palace Museum, Taipei.

Ring-shaped, slightly triangular in cross-section, but the sides near the inner wall are slightly flattened, and the surface is polished smooth; the inner wall is straight, but not very regular. The outer edge of the device is blade-shaped and has flaws. The surface of the vessel is thought to be stained green by patina and has many flaws. In the Hongshan Culture of the late Neolithic Age, ring objects similar to this type once appeared, and later in the Warring States Period, similar jade rings also appeared again and again.