The rock is nearly seven metres from end to end and just over a metre high at its eastern end, and across six metres of its surface someone, at some point in prehistory, pecked dozens of carefully arranged marks into the rough stone. What makes it quietly arresting is not any single motif but the density and variety of them, spread across the rock in clusters, connected by grooves, and varying from the boldly clear to the barely-there.

The markings belong to the tradition known as cup-and-ring art, a form of prehistoric carving found widely across Atlantic Europe in which a small hemispherical depression, the cup, is surrounded by one or more concentric carved rings. At Kealduff, the repertoire goes considerably further than simple cups with a ring or two. The eastern end of the boulder holds the most complex arrangements: two cup-and-five-ring motifs sit close together, one of them truncated by a natural fracture in the stone. A cup-and-four-ring motif nearby has a radial groove, a channel cut outward from the cup through the rings, that extends 42 centimetres before narrowing to a close. That motif is then linked by a short groove to a triple cup-and-ring arrangement, three conjoined cups sharing their rings, which in turn connects by another groove to further elements. At the western end, three cup-and-two-ring motifs accompany something rarer: an interrupted spiral, formed by a cupmark and radial groove enclosed within four rings that do not quite close, each one terminating just short of where it began. This gapped or penannular quality, rings left deliberately open, appears elsewhere in the cup-and-ring tradition but is less common than the fully enclosed form. The site is documented in the archaeological survey of the Iveragh Peninsula compiled by A. O'Sullivan and J. Sheehan, published by Cork University Press in 1996, which catalogued it as part of a broader effort to record the prehistoric landscape of south Kerry. The boulder looks out over the Behy river valley and the surrounding mountains to the north-east and east, a setting that may or may not have mattered to whoever chose this particular outcrop, but which gives the site a quality of openness unusual for something so intimate in scale.