It measures roughly 28 centimetres high, 40 centimetres wide, and 28 centimetres thick, closer in size to a large kerb-stone than anything that might announce itself as a grave marker. What distinguishes it is on its eastern face: the outline of a cross, formed not by carving in relief but by a shallow incised groove barely half a centimetre deep and about one and a half centimetres wide. The restraint of the decoration is striking. This is not a piece made to be admired from a distance; it rewards close attention.

The slab is catalogued by Corlett in 2003 as Slab 3 among the grave markers associated with the Dunboyke church complex, a site that itself carries considerable age. Grave slabs of this kind, where a cross outline is simply scratched or grooved into the stone surface rather than carved in full relief, are among the earlier forms of Christian grave marking found in Ireland, and the use of local granite here fits a pattern of modest, practical commemoration. The positioning of the slab immediately outside the south-western angle of the nave places it at the edge of the ecclesiastical space, on ground that slopes away to the south-west, which may reflect both the topography of the site and the particular traditions around burial in relation to a church's footprint.