Andrew McIntosh

“Faerie stones can be found in a variety of regions, being particularly common in Cornwall and the Isle of Man. They are unimpressive in appearance and hard to recognize with the untrained eye; their most distinguishing feature is their perfect roundness. They seem primarily to be used to store enchantments for later use or perhaps for the purposes of gift-giving. Danielle de Grey's 1850 Guide to Elfstones of Western Europe is the definitive resource on the subject. (I am aware that many dryadologists today ignore de Grey's research on account of her many scandals, but whatever else she was, I find her a meticulous scholar.) A faerie stone with a crack down it has been spent and is thus harmless. An intact stone should be left untouched and reported to ICAD, the International Council of Arcanologists and Dryadologists.”
― Heather Fawcett, Emily Wilde's Encyclopaedia of Faeries