This is a bullaun stone, a type of rock featuring one or more bowl-shaped basins that appear across Ireland in considerable numbers, often near early Christian sites, holy wells, or ancient field boundaries. What makes the Drummin example quietly puzzling is that nobody is entirely certain where it originally came from.

The boulder measures roughly 1.05 metres by 86 centimetres, and its basin, 28 centimetres by 30 centimetres and about 7 centimetres deep, sits off-centre within the upper face. Bullaun stones are among the more enigmatic categories of early Irish monument. The basins may have been used for grinding, for collecting rainwater thought to have curative properties, or for ritual purposes that remain a matter of debate among archaeologists. The water that collects in them was sometimes credited with healing powers, particularly for skin complaints, and local traditions around such stones survived well into the modern period. The Drummin stone is described as having been found locally, though its exact original location has not been recorded, which means it has been separated at some point from whatever context, religious, agricultural, or otherwise, first gave it meaning.