To archaeologists, it is a bullaun stone, a term used for cup-shaped depressions ground or pecked into natural rock or boulders, found widely across Ireland and often associated with early medieval religious sites. To the people who have lived near it, it has always been something more immediate: a wart well, a place where the afflicted might seek a cure.

The site was recorded by O'Kelly in 1944, who measured the hollow precisely: roughly 0.3 metres across at the top and 0.38 metres deep, dimensions that place it at the smaller end of the bullaun spectrum. That double identity, the archaeological classification sitting alongside the folk name, is not unusual in Ireland, where bullauns have long attracted curative traditions, often involving water that collects naturally in the depression. The rain-filled hollow becomes, in folk practice, the active ingredient. Loughgur itself is one of the most significant prehistoric landscapes in the country, a lake-shore environment with evidence of continuous human activity stretching back thousands of years, which gives even a modest, easily overlooked feature like this one a layered kind of significance.

The stone sits in its natural outcrop rather than having been moved or displayed, so finding it requires some attention to the landscape rather than a signpost. Loughgur is well known for its stone circle and interpretive centre, and visitors who confine themselves to those attractions may walk past features like this one without registering them. After rain is arguably the best time to appreciate a wart well, when water pools in the hollow and the logic of the folk tradition becomes immediately legible. Look for the outcropping rock rather than a freestanding stone, and take note of the scale: just over a foot across, deep enough to hold water, worn smooth where the rock meets the air.