What makes it remarkable is the face looking out from its western surface: a crucified Christ with a disproportionately large head, wide round eyes, arched brows, and a mouth incised in what reads unmistakably as a slight smile. It is among the earliest known figurative representations of the crucifixion in Ireland, and the expression alone sets it apart from almost anything else in early Irish stonework.

The slab is trapezoidal in shape, roughly a metre wide and just over a metre above the current ground level, though the lower legs and feet of the carved figure are now buried beneath the surface. The crucifixion scene is incised, meaning cut into the stone in shallow lines rather than carved in relief, and it fills the entire face of the slab. Christ's fingers are individually delineated, a nail is visible in his right palm, and slanting grooves mark his ribs, radiating from a central vertical line that expands at the top into two small spirals indicating the nipples. Flanking the main figure, and rendered in profile at a smaller scale, are Stephaton and Longinus, the sponge-bearer and lance-bearer named in medieval tradition. Stephaton holds a long shaft tipped with a small concave circle, representing the vinegar-soaked sponge, positioned just below Christ's chin; Longinus pierces the ribs with his spear. In the two upper quadrants of the cross, small incised Greek crosses may represent the thieves crucified alongside Christ. The scholar Peter Harbison, writing in 1987, placed the slab in the ninth to tenth century and noted its close stylistic relationship with a comparable crucifixion slab on Duvillaun Island, some five and a half kilometres to the south, itself associated with an early ecclesiastical settlement including a cashel (a stone-walled enclosure typical of early Irish monastic sites), a church, and a holy well.

When Françoise Henry excavated the ruined house on the Bailey Mór mound in the early 1940s, she established that the rough cross-wall supporting the slab had been built specifically to hold it upright, and that this was done long after the house itself had fallen into ruin. Where the slab originally stood is not known. The carving is shallow and now considerably weathered, and white lichen covers much of the stone surface, which means the detail is far easier to read in good, raking light than in dull or overcast conditions.