I read someone was calling these goddess rocks. For some reason that gives me a huge belly laugh every time I hear it. To me they will always be hagstones.
There are several traditional uses for hagstones. 1) look through them to see fairies. 2) hang them on your door frame to keep out witches. 3) string it on your key chain to protect you and your house. 4) Hang it on the barn door to keep your horses from being hag ridden. I do use it for some of those things, but mostly I use it as a charm tied on a cord with knots. Each knot is a location I wish to travel to in my dreams, and as I pass the knots through the hole they go into the otherworld/elphame and I find myself going there in my dreams, just as I planned. I specifically learned about this method from an article by Andrew Chumbley called “What is Traditional Craft?” http://xoanon.co.uk/archive/what-is-traditional-craft/