This abstract cong tube is composed of dark olive green and tan jade. The inner wall of the cylinder is well rounded and smoothed, with a mark of drilling. Cong tubes were probably used for rituals to heaven. Cong tubes of this shape in Neolithic Northwest China were revived during the Shang and Western Zhou dynasties in the Bronze Age. Together with the bi disc, the cong tube has been a favored archaic shape for Chinese arts not only in jade, but also in ceramics throughout 4,000 years. One interpretation is that they signify the combination of the circular heaven and the square earth.
