The boulder is not large, roughly a metre and a half in its longest dimension, but on its south-west-facing face someone, at some point in prehistory, carved a series of cup-shaped hollows and geometric forms into the rock. These are the kinds of marks found across Atlantic Europe from the Neolithic into the Bronze Age, and they remain genuinely mysterious: no consensus exists about whether they served a ritual purpose, a territorial one, or something else entirely.

The decorated surface is sub-rectangular, measuring about 60 by 55 centimetres, and contains several distinct motifs. Cupmarks, which are simply small, round, deliberately carved depressions, appear here in varying sizes: the deepest reach about 11 millimetres into the stone, while shallower examples are still clearly legible. Alongside these is a cup-and-ring mark, a cupmark surrounded by a carved circular groove, though this particular example is faint compared to the plainer hollows beside it. There is also a half-cupmark and what has been recorded as a cup-and-radial groove. The motifs sit on a weathered, lichen-covered surface on a boulder that is itself rough and fractured, the stone fractured likely by centuries of frost and rain. Tributaries of the Kealduff River run to the north and south of the knoll, and a larger boulder sits about three metres to the south-south-east of the carved stone, its relationship to the decorated example unrecorded.