We have seen in the past that concretions — the precipitation of minerals around particles — usually take spherical or oval shapes, as in the case of Klerksdorp Spheres and Moeraki boulders. Pearl is another good example of concretions. But concretions can also take unusual shapes.

In the Harricana River valley in the Abitibi-Témiscamingue administrative region of Quebec, Canada, concretions occur as flat discs, smooth on one side and puffed up on the other with gorgeous patterns. They were formed over thousands of years by deposition of calcium carbonate over small pebbles and fossils. The Indians have called them “Fairy Stones” since hundreds of years, and used to carry them as lucky charms when they went on fishing or hunting expeditions. They believed that wearing a Fairy Stone would protect them against bad spirits and bring them good health and prosperity.