The hag stone is a folk name for any stone or pebble which has a natural hole running all the way through it, which was created by hundreds, if not thousands, of years of water erosion caused by the ebb and flow of the sea. There are various meanings behind the Hag Stone, and finding such a stone is believed to be extremely fortuitous.

The holey, or 'Holy' Hag stone represented the sacred circle, the wheel of life, and the Mother Goddess. It was considered a spiritual gateway, and it was said that if you peered through the hole at dusk you would see the creatures of the otherworld. The Hag Stone was also sometimes called a Wishing Stone, and could be held in the left hand and rubbed to make wishes come true.

It is quite rare to find a natural Hag Stone; they are more common on beaches, but can sometimes be found inland, in the earth over which ancient seas used to flow.