Known locally as the christening stone, it is a bullaun, a type of stone bearing one or more deliberately ground hollows that appear frequently at early Irish ecclesiastical sites. The hollow here is roughly circular, about 33 to 36 centimetres across and 8 centimetres deep, worn into the near-centre of a subrectangular stone measuring roughly 90 by 82 centimetres. It was recorded in 1939 by Hartnett as having a local reputation for curing warts, a folk belief attached to bullaun stones in many parts of Ireland, where the water that collects in the hollow was considered to carry some curative or sacred power.

The stone originally stood on the western side of an enclosure at Coolflugh, on what is said to have been the site of Inishleena Abbey. In 1956, archaeologist Fahy excavated the area ahead of a significant intervention: the flooding of the Lee Valley as part of the Lee Valley Hydro-electric Scheme. At the time of excavation the bullaun was still sitting as it had long been arranged, supported by four small boulders. Rather than leave it to the rising waters, it was removed and eventually placed in the grounds of Cloghroe National School, where it remains. The abbey site itself, along with much of the surrounding landscape, now lies beneath the waters of the reservoir created by the scheme, making this displaced stone one of the few tangible remnants of what was once there.