In the above picture are two hag stones in my personal collection. The larger one was found and the smaller one was purchased.
Hag stones, a.k.a. holy stones, holey stones, adder stones, or hex stones, are literally stones that have one or more naturally made holes going all the way through them. They are formed over long periods of time by flowing water that eats away weaker parts of the stone.
The lore and powers of the hag stones come from European folk magic, Celtic to be precise. The lore of hag stones is incredibly ancient. The Druids of Gaul called them "serpent eggs" or "adder stones" and believed they were created by the secretions of a large mass of snakes, with the holes formed by the serpents' tongues. They were thought to be so powerful that anyone who possessed one could have power over kings and gain victory in anything they desired. Pliny the Elder even claimed that Emperor Claudius had a man executed merely because he wore one in order to win a legal dispute.
The name hag stones literally means "witch stone". It gets it's name because it is believed these stones have the power to protect from witchcraft and repel witches. Besides these qualities, hag stones are also said to grant the owner the ability to see the fairies and spirits, as well as to see through any spell or glamour (a spell or power to make something appear more attractive or desirable than it actually is), by holding the stone to the eye and peering through the hole. In Christian times it was believed the stones gave the owner the ability to see through the tricks of the Devil. Additionally, hag stones were believed to be good for healing and especially diseases and conditions such as arthritis and gout, as well as any diseases brought upon through witchcraft.
Hag stones can be used as pocket pieces, kept on windowsills or above doorways, and strung on cords and hung up in windows or worn as necklaces. I've also read that hag stones are employed to this very day by certain sailors who attach them to their ships to prevent storms conjured by witchcraft.
The most powerful hag stones are those you personally find. You can find them in various locations, such as on beaches and in river and creek beds. However, I found mine at my employer at the time. I had two large hobnail vases that I decided I would fill with some of the decorative gravel at my work. The gravel was actually quite beautiful, lots of natural reds, oranges, greens, browns and grays. I then filled the vases and kept them as decoration at my then apartment. When I tired of them and was going to throw them out I chanced to look at them more carefully. It was then that I found my "gem" It had two holes going clear through and I immediately knew it was a hag stone and could prove valuable to me. I've had it nearly 12 years now. The smaller hag stone in the picture I purchased at an occult shop and it too has two holes that go clear through.
A ward of warning about hag stones. The manufacturing and selling of fake hag stones is increasing. Some vendors are at least honest and will state that these are hag stones they created themselves by boring holes in stones. Others will openly deceive people into thinking they are purchasing the genuine thing. A fake hag stone is worthless and has no power. The hole(s) must be made by nature or else all you have is a rock. If you are going to purchase a hag stone online take a close look at the picture or if you are buying it in person examine the piece. If it appears too perfect then it's probably fake.