It measures barely a third of a metre in length, irregular in shape, and worn to a modest thickness. At its centre is a single circular depression, roughly thirteen centimetres across and five centimetres deep. That hollow is the point of the thing. This is a bullaun stone, a class of carved or ground stone found across Ireland, typically associated with early Christian or pre-Christian sacred sites, and thought to have been used in ritual or devotional practice, possibly for grinding, possibly for collecting water considered to have curative properties.

Bullaun stones turn up repeatedly in the company of holy wells, and this one at Kilbree is no exception. The pairing is not coincidental. Holy wells in Ireland were often focal points for patterns, the term used for the seasonal devotional visits that took place at such sites, usually on the feast day of an associated saint. The stones beside them, with their worn depressions, may have served as receptacles for votive water, or as grinding vessels, or both at different points in their long use. The Kilbree example is small enough to be walked past without a second glance, which makes the precision of that central depression all the more striking. Someone worked this stone deliberately, creating a feature that has outlasted whatever community of practice first made use of it.