[five] Engraving on bone and ivory is an important technique to the Art on the Upper Paleolithic, and bigger engraved petroglyphs on rocks are observed from several prehistoric durations and cultures around the world. Knife gravers are for line engraving and very deep cuts. Spherical gravers, and flat gravers https://johnathan78o65.topbloghub.com/41744805/what-does-marble-engraving-mean