The result is a bullaun, a type of ancient hollow ground into rock, most often associated with early Christian sites in Ireland, though their origins and exact purposes remain genuinely debated. This particular example sits within a carefully squared-off section of the boulder's surface measuring just over a metre by sixty centimetres, as though the maker wanted the hollow to occupy a defined, almost architectural space rather than simply appearing wherever the stone permitted.

The boulder itself is substantial, roughly 2.2 metres on each side and about 60 centimetres thick, and its surface has been worked flat to receive the bullaun, which measures 34 centimetres across and 16 centimetres deep. That combination of a dressed, levelled surface and a geometrically framed depression is what makes this example quietly unusual among such stones. Bullauns are common enough across early Christian Ireland, often found near churches or holy wells, where the water collected in them was sometimes believed to carry curative properties. The area known as Sevenchurches is another name for the Glendalough monastic complex, one of the most significant early medieval ecclesiastical sites in the country, which lends this otherwise modest stone a suggestive context. It was recorded and drawn by Patrick Healy in a 1972 survey of ancient monuments at Glendalough carried out for the Office of Public Works, and that unpublished report remains one of the primary sources for lesser-known features in the valley beyond the well-visited round tower and cathedral.