Thomas Lawton opinion 11/7/90: could have been cut down
The production of jade discs started in Neolithic times in China and continued until the 19th century. The earlier ones are usually without carved patterns, like this example.
Jade discs came in all sorts of sizes. Chinese philologists habitually made a distinction between a disc with a small central hole, a 'bi', and one with a large central hole, a 'huan'. This disc would have been considered a 'huan'.