The result is one of the more elaborate surviving examples of prehistoric rock art on the Iveragh Peninsula: a roughly wedge-shaped outcrop whose decorated surface measures around 2.25 metres by 1.3 metres, covered in a dense, deliberate arrangement of cupmarks, concentric rings, and radiating grooves. What makes it particularly unusual is the presence of a cruciform motif near the eastern end of the surface, a form rare in Irish prehistoric rock art. Each of the four arms of the cross terminates in a small cupmark, and those cupmarks are themselves enclosed within penannular rings, meaning rings left intentionally open at one point, like a letter C rather than a full circle. Further cup-and-ring motifs spread across the rest of the surface, most of them sending a long radial groove outward from the innermost ring, as if each design is reaching toward something just beyond its own boundary.

Cup-and-ring marks are the most widespread form of prehistoric rock art in Atlantic Europe, appearing from Galicia to Scotland, and typically dated to the late Neolithic or early Bronze Age, roughly 3500 to 1500 BC, though the Kealduff stone has not been independently dated. What the symbols meant to the people who made them remains genuinely unknown. The Kealduff surface was documented in A. O'Sullivan and J. Sheehan's 1996 archaeological survey of the Iveragh Peninsula, which catalogued it as one of several rock art sites in the area. The motifs are picked rather than scratched, meaning the maker used a harder stone to peck the designs into the surface rather than dragging a tool across it, and the execution is described as finely done and well preserved, which is notable given that parts of the surface have been visibly affected by weathering and encroaching vegetation. An unusual additional feature is what the survey records as an 'M' scribble, a roughly 34-centimetre mark whose relationship to the prehistoric designs is unclear.

The boulder sits in a natural hollow on an east-facing slope, with views across the River Behy valley and the surrounding Kerry mountains. That hollow, however, is increasingly engulfed by furze, the dense, thorny shrub common to Irish uplands, which has begun to obscure some of the motifs at the edges of the decorated surface, where radial grooves disappear beneath the growth. Two small streams run close by, one roughly four metres to the east and another about five metres to the southwest. The site is not signposted or formally managed, and the combination of mountain heath terrain and enclosing vegetation means the stone requires some searching out even once you are in the right area.