Not because it is buried or lost, but simply because the river is usually too full. Only when water levels drop unusually low does this bullaun stone emerge, its single circular basin sitting quietly in a rock measuring roughly 1.8 metres by 1.1 metres, waiting to be noticed.

Bullaun stones are boulders or bedrock surfaces into which one or more rounded depressions, called basins, have been deliberately carved. They are found across Ireland, often near early ecclesiastical sites, and their purpose remains genuinely unclear; theories range from liturgical use to grain grinding to the collection of water thought to have curative properties. This particular example sits in the Glendasan River at the site known as Sevenchurches, part of the broader monastic landscape of Glendalough, and it is one of four bullaun stones recorded in close proximity to one another. The submerged stone lies some 18.5 metres north-west of another in the group. Its single basin is modest in scale, around 30 centimetres across and 13 centimetres deep, but the fact that it rests within the river rather than on dry ground beside it sets it apart from the others nearby. Healy, writing in 1972, noted its location and dimensions, suggesting the stone had been recognised and recorded even when most walkers passed by without knowing it was there.

The stone is only visible when the Glendasan runs low, which tends to occur during dry spells in late summer or early autumn. There is no guarantee of a sighting, and anyone hoping to find it should be aware that river conditions vary considerably from year to year. Looking carefully at the riverbed from the bank, rather than wading in, is the more practical approach.