That uncertainty is, in its own way, the most interesting thing about it. Rock art of this kind, typically consisting of shallow cup-shaped depressions pecked into the surface of a boulder, is among the oldest human mark-making found in Ireland, generally associated with the Neolithic or Bronze Age. The Ballykean example was recorded as bearing eight such cups, two of them connected by a carved channel running between them, on the flat upper face of a block roughly six feet by five and a half feet, and standing about two feet high.

The stone was documented by Kinahan in 1884, with enough locational detail that the site could be revisited. When it was inspected in 1990, however, the boulder could not be found. This is not entirely unusual. Stones of this kind have been broken up for field walls, buried under shifting soil, or simply swallowed by vegetation over the course of a century. Kinahan's original description remains precise and vivid enough to suggest the stone was real and observable in his time, which makes its absence a minor puzzle rather than a dismissal. The carved channel linking two of the cups is a detail worth noting; cup-and-channel arrangements appear at other Irish rock art sites and are thought to have carried some intentional, if now unreadable, significance to the people who made them.