Bi-discs, circular stone discs with a central hole, first made in the Neolithic period as simple slices of stone, just ground to achieve a smooth even surface, later gradually developed into sophisticated jade and nephrite discs with carvings of dragons and other mythical beasts.
The circular shape symbolizes the earth, sun and sky as well as eternity since there is no beginning nor end.
Bi-discs were cult objects, buried together with their owner. They were the symbol of status and power and only for the aristocracy.
As the bi-discs were just found in modest sizes in our modern time, both have been considerably enlarged to give them a more impressive visual aspect.