What makes it quietly odd is a detail easy to miss: its two arms are not matching. One is rounded, the other angular, as though the carver either changed their mind partway through or was working from two different templates at once. At 0.73 metres tall and 0.58 metres wide, it is not a large object, and at just five centimetres thick it has a flat, almost schematic quality, more like a marker than a monument.

Skelligs Mhichíl, the larger of the two Skellig islands off the tip of the Iveragh Peninsula in County Kerry, was home to a community of monks who, from perhaps the sixth or seventh century onwards, built their beehive cells and oratories on a near-vertical crag some 230 metres above the sea. The monks' graveyard beside which this cross stands was the community's burial ground, and crosses of this kind, often simple incised or free-standing slabs, were typical grave markers in early Irish monasticism. They were rarely decorative in any elaborate sense; function and faith were the point. The asymmetry of this particular cross has no documented explanation, and the 1996 survey by A. O'Sullivan and J. Sheehan, which first recorded it in detail, offers description rather than interpretation. Whether the difference between the two arms reflects different hands, different periods of carving, or simply the pragmatic use of whatever stone was available on an island where every material had to be carried up hundreds of steps, remains an open question.