An ancient Chinese jade artifact. The earliest cong (pl.) were produced by the Neolithic Liangzhu culture. Later examples date from the Shang (ca. 1500–1050 BCE) and Zhou (ca. 1046–256 BCE) dynasties. In form, a cong is a hollow cylinder embedded in a  rectangular block. Proportions vary: some cong are squat, others are taller than they are wide. The outer surfaces are sometimes decorated with mask-like faces. Although generally considered to be ritual objects, the original function of the cong is unknown. Web resource here.

Jade Cong. Liangzhu culture. Ca. 2500 BCE. Private Collection.