Throughout the jade-mining history in China, Hetian jade has always occupied the center stage. Hetian jade, found in southwest Xinjiang Autonomous Region in Northwest China in the Spring and Autumn Period (770-476BC), has a history of more than 2,000 years. Most of the imperial jade seals were made of Hetian jade, which has been considered as the "real jade". The saying that "gold is costly, but jade is priceless" is in recognition of Hetian Jade. But after a long time of excavation, resource of Hetian jade is dwindling. It was at this time that Kunlun jade was discovered.
The manufacture of Chinese jade articles was already highly developed by the Shang Dynasty (16th to 11th century B.C). The Chinese of this period had the technology to produce jade articles of every imaginable type, shape, and size. By the end of the Chou Dynasty (11th century to 256 B.C.) and the beginning of the Han Dynasty, Chinese jades reached a second peak in their development; craftsmen had more advanced tools as well as more efficient methods of polishing jade and creating unsurpassed masterpieces. From this point on, jade craftsmen could accommodate practically any and every customer demand.
When polished and carved into various objects, jade was attributed with certain cultural characteristics. In ancient Chinese cosmology, the heaven was considered to be round, and the earth square. Thus a round jade ornament with a hole in the center, called a "pi", was carved to honor the gods of heaven, and a long hollow jade ornament with rectangular sides, called a "ts'ung", was made to honor the terrestrial spirits.