This is an exceedingly rare Chinese yellow jade 聯璜壁 (Joint Jade Arc Bi Disc), engraved with Chi-dragons and Kui-dragons, and grains popular in Eastern Zhou through Han Dynasty, likely dated to Warring State period (around 500 BC). There are a lot of beautiful and detailed carvings on the disc, but sadly my camera failed to catch them. But anyway, for antique jade you have to come and inspect it in person. It is so exquisite and convincing, particularly with natural soil encrusted surface.
The diameter is about 12 cm.
Cash only.