a white and russet jade disc BI, Probably Han Dynastya white and russet jade disc bi, of circular form pierced with a cental aperture, densely carved to both sides with spiral patterns enclosed within line borders, the stone of a white and russet tone,when zooming in for 60 to 100 times to observe the tiny marks on the lot, marks of using soft abrasives could be seen, such marks are very different on modern jade pieces where new machines are used for carving and polishing.Provenance: private English collection6.5cm diameter