A Hag Stone is simply a stone with a natural hole through it. In folk magic systems, these are often believed to ward off the dead, curses, witches, sickness, and nightmares. They are also used as windows or doorways to see 'otherworlds', invisible spirits, or how a being 'really' looks beyond their glamoury. When worn around the neck a hex stone acted as an amulet and protected the wearer from the 'evil eye'. The theory being that anyone who attempted to use the the evil eye would have their attention drawn to the stone and therefore be unable to work their black magic.