Measuring less than forty centimetres in height, it carries the faint outline of a Latin cross, cut in shallow grooves now heavily worn by time and weather. It is not a grand monument, but the fact that it survives at all, in pieces, retrieved from rubble, makes it quietly compelling.

The slab was found in the debris to the south of a structure known as Cell B, one of the clochans associated with the island's monastic complex. A clochan is a dry-stone beehive hut, characteristic of early Irish monasticism, and High Island supported several of them alongside a church. The cross-slab was recorded by Fisher in 2014, who documented it as a linear Latin cross, meaning one defined by plain incised lines rather than carved relief. The stone itself is garnet mica-schist, a metamorphic rock with a distinctive crystalline structure. At just four centimetres thick, it was never a large or imposing object; it may have served as a grave marker or a simple devotional stone within the monastic enclosure.

High Island is accessible only by sea and only in favourable conditions, which means the settlement and everything within it remains largely undisturbed. The broken slab and the rubble it came from are part of a site that has seen very little interference, which is precisely why fragments like this one still turn up at all.