Bullauns are boulders or slabs of rock into which one or more circular depressions have been deliberately ground, typically by rotating a smaller stone within the hollow over a long period. They are among the more quietly persistent objects in the Irish countryside, turning up in churchyards, beside holy wells, and in open fields. Their precise purposes are debated; some are thought to have been used for grinding grain or preparing pigments, while others accumulated layers of ritual association over the centuries, becoming sites of cursing, healing, or prayer. The water that collects in their hollows was often regarded as curative.