In prehistoric times, early polished jades were made with stone-working technology and some wood-, tooth-, bone- and shell-working and pottery-making techniques. These means can be called “prejade-working technology. ” It is formed of chipping, cutting, polishing and drilling techniques for producing stone implements and decorating techniques of wooden, tooth, bone and pottery objects, and is characterized by independence and a compound character. In the Hongshan culture, Lingjiatan complex and Liangzhu culture, the shaping, trimming, picking and carving in intaglio and relief were all operated on the emery wheel. The invention of this device was an important technical innovation. It prompted the thorough separation of jade working from stone tool fabrication and much contributed to the establishment of the "scraping and polishing techniques" as an independent handicraft.
