Jade Cong Tube

Hollowed jade tubes like these are called cong (tsong), and they were used as grave goods during the Neolithic period (c. 8000-1900 BC) in China. They come in many sizes but each is a square tube around a circular hole. Although it is not known what they symbolized originally, scholars since ancient times have theorized that the inner circle represents heaven, and the outer square represents earth.