A Hag Stone is a stone that can be found in nature with natural holes in it. Other names for these stones include Holy Stones, Odin Stones, Faerie Stones, Adder Stones, witch stones, serpent’s eggs, or snake’s eggs.
In folk lore, these stones are rumored to ward off the unwanted spirits, curses, sickness, and nightmares. They are also said to be used as “windows or doorways to see ‘otherworlds’, invisible spirits, or how a being ‘really’ looks beyond their glamoury.”
They can be placed above the entrance to one’s home to absorb negativity that may enter. They can also ward off night hags and have for centuries been known as a favorite talisman by Cunning Folk to dispel the evil eye. In Italian witchcraft it is believed that gazing through these stones can allow one to peer into the fae realm or the stones could even be a key into the realm of the fae.
They can even break illusions that are cast by evil witches or the fae.
“The legendary druid Mug Ruith was said to have a stone which could turn into a poisonous eel when thrown in water, this may be a reference to an Adder Stone.”