Standing just over a metre and a half above the ground near the building known as the Priest's House, it is not the tallest stone, not the most elaborately decorated, and carries no inscription legible to a passing visitor. What it has is a single incised Latin cross, its shaft terminating in slightly flared, expanded ends at top and bottom, cut with a restrained precision into grey mica schist. That quiet geometry is its whole argument.

The stone was catalogued by Patrick Healy in a 1972 Office of Public Works survey of ancient monuments at Glendalough, where it appears as number 168. Healy recorded its dimensions carefully: 0.65 metres wide, roughly 0.11 metres thick on average, a rectangular slab of mica schist, a metamorphic rock common to the Wicklow Mountains, with a characteristically layered, glittering surface. The cross itself is described as a single-line incision, small relative to the face of the stone, with those expanded terminals giving the shaft a subtle emphasis at both ends. This type of cross-slab, in which a simple linear cross is cut directly into a standing stone rather than carved in relief, is one of the older forms of Christian monument found at Irish monastic sites, often associated with grave-marking or the demarcation of sacred space. Its precise date is not recorded, but the form is consistent with early medieval practice at a site like Glendalough, which grew from a hermitage founded by St Kevin in the sixth century into one of the most significant monastic complexes in Ireland. The slab sits approximately 2.1 metres to the west-northwest of the north-west corner of the Priest's House, a Romanesque structure that is itself one of the more enigmatic buildings on the site.