The decorated area is modest, barely forty centimetres across, and its SE-facing aspect sits flat and unassuming on a stone that rises only about half a metre from the ground. What was carved there, however, belongs to a category of prehistoric art found across Atlantic Europe and still not fully understood: cup-and-ring marks, shallow circular grooves pecked or ground into rock surfaces, their original purpose a matter of ongoing speculation.

The motif at Kealduff consists of a penannular cup-and-four-ring, a central cup mark surrounded by four concentric rings that are almost, but not quite, closed, giving the design its penannular quality. The central cup is four centimetres in diameter and five millimetres deep, while the rings themselves are roughly a centimetre wide. From the cup, a linear groove extends 28 centimetres outward in a south-south-westerly direction, a feature known as a radial groove, which is a common but not universal element of this type of rock art. A separate cupmark, unaccompanied by rings, sits about ten centimetres to the south-east. The overall span of the ringed motif is 31 centimetres. The site was documented in the Iveragh Peninsula archaeological survey by A. O'Sullivan and J. Sheehan, published by Cork University Press in 1996.

The stone sits roughly 0.75 metres south of a field boundary that runs east to west, and heavy overgrowth has long made the motifs difficult to see. Trees along the boundary also block what would otherwise be views across the River Behy valley. The carvings are described as well-preserved beneath that vegetation, but finding and reading them requires patience and, ideally, a low raking light, which tends to throw shallow incised marks into sharp relief in a way that direct or overhead sunlight cannot.