It is a cruciform cross-slab, cut into the shape of a cross rather than simply inscribed with one, and it survives in a fragmentary state: broken along one edge and at both ends, measuring just 41 centimetres in height and 25 centimetres across at its widest point. What makes it quietly compelling is not any decorative ambition, because the surface is entirely plain, but the fact that it exists at all, shaped with intention and then lost, for however long, beneath fallen stone.

The slab was found in rubble to the south-west of a structure known as Cell B, a clochan situated to the east of the early church on High Island. A clochan is a dry-stone beehive hut of early medieval type, associated across the west of Ireland with monastic settlements where monks lived and worked in conditions of considerable austerity. High Island, lying off the coast of Connemara, was the site of one such settlement. The slab itself was recorded by Fisher in 2014, who catalogued it among the early Christian material from the island. Its material, garnet mica-schist, is a metamorphic rock whose flecked, crystalline surface would have caught the light in a way that plain limestone would not, though whether that quality played any part in its selection is impossible to say.