Disk (<em>bi</em> 璧)

Perforated disk of the type pi [bi] 璧; bored mostly from one side; mottled light to dark shades of brown with scattered spots of greenish translucent strata; profuse grayish coating of disintegration, especially in veins and breaks; proportions and surface contours uneven. (Rim and some surface areas roughened with chips and cracks.)