Stone Axe - From shell mounds of Song-do, Yeosu While the skills of polishing a partial edge of a stone axe were found some remains over the world since the middle of the later Paleolithic Age, the skills of polishing an entire stone implement were generally used in the Neolithic Age. In Korean Neolithic Age, there were 2 kinds of implements made by different skills. One was polished stone implement and another was chipped stone implement. Polishing skill was already generally used in the early Neolithic Age.