The Lodestone Etching Series

‘Lodestones are naturally magnetized pieces of the mineral magnetite.[1][2] They are naturally occurring magnets, which can attract iron. The property of magnetism was first discovered in antiquity through lodestones.[3] Pieces of lodestone, suspended so they could turn, were the first magnetic compasses,[3][4][5][6] and their importance to early navigation is indicated by the name lodestone, which in Middle English means "course stone" or "leading stone",[7] from the now-obsolete meaning of lode as "journey, way".

Source: Wikipedia