It is not much to look at in conventional terms: just over forty centimetres tall, sixteen wide, and a mere three centimetres thick. What makes it worth attention is the restraint of its design. There is no carving, no inscription, no ornamental knotwork. Instead, pairs of small rounded notches cut into the edges of the slab, on both faces, trace the outline of a cross through absence rather than addition. The form is implied rather than stated, which gives the object an unexpectedly quiet authority.

The slab is made from garnet mica-schist, a metamorphic rock that catches the light with faint mineral sparkle, and its slightly tapering profile ends in a pointed foot that appears to be the result of natural breakage rather than deliberate shaping. It was found in rubble to the east of the church on High Island, a site long associated with early Christian monasticism on Ireland's Atlantic fringe. Cross-slabs of this kind, simple markers used to denote burials or devotional sites in early medieval Irish monasteries, were often left undecorated or only minimally worked, relying on shape and placement rather than elaborate ornament to communicate their sacred function. This example, recorded and measured by Fisher in 2014 and referenced in the earlier survey by White Marshall and Rourke, represents one of the more pared-back survivors of that tradition, its cross visible only to someone who knows to look along the edges rather than across the face.