The boulder measures 2.5 metres long, 1.3 metres wide, and stands 1.1 metres above the surface. What makes it quietly arresting is not merely its scale but the deliberateness of its arrangement, and a single drill-hole cut into its upper north-western surface, a detail that hints at human intention without fully explaining it.

Boulder-burials are a form of prehistoric monument found particularly in south-west Ireland, in which a large capstone is raised on smaller support stones, typically over a burial deposit. They are distinct from the better-known portal tombs and wedge tombs of the same broad tradition, tending to be lower and less formally structured, though the underlying purpose appears similar. The example at Rathruane More sits on a natural rock ridge, suggesting that whoever placed it here was responding to the existing landscape rather than working against it. The drill-hole on the upper surface is harder to account for; such features occasionally appear on prehistoric monuments and may relate to later activity at the site, though at Rathruane More the detail remains unexplained in the available record.