Sea treasures! The stones are called Hag stones, they’re used for protection against negative spirits, nightmares and eye diseases, they can hung from a string at the front of your house for protection, used by farmers to protect livestock from enchantments and fishermen for a safe journey and a good catch. Witches have used them for centuries for healing and spell work, they’re are also a powerful tool to the Druids. If you look through the hole you are meant to see Fairies, through a disguise and to spot traps. It’s said that if you find them you’re in the favour of the goddess Diana. There is tons of Lore surrounding these stones.