Vintage jade "bi" round pendant or small carving with rotating ball in center. Size is 48 mm across, 12 mm thick in center. Both sides are same color and carving all around. "Bi" is the symbol of Heaven. There is a hole at the top you can see in the photo where a "Dragon Whiskers" adjustable silk cord can be attached to wear as a pendant. Or you can use it like a jade carving as it is with the silk cord 1" loop already attached.
This is a vintage old jade piece I purchased in China during one of our shopping trips several years ago in a small local market in Tianjin.