The irregular surface seen in the hole of authentic jade artifacts of many periods is believed due to the result of particular instruments different from modern ones. As such, those holes are difficult to intimate applying modern tools for fake jades. In addition, holes of artifacts of different periods are shown to have particular patterns. Generally speaking, holes of Hongshan and Liangzhu Cultures jades share same patterns of dual holes having an irregular inner surface or helical scoring on the same side. Jade artifacts of the Xia Dynasty
have holes carved and polished from both sides. Holes of Qijia Culture jade artifacts are seen one directional drilling with the irregular remains at the end. As a result, hole drilling patterns of different cultures are vital factors to be considered in jade identification.