It measures just over half a metre in length, irregular in shape, and its surface is concave, slightly hollowed by age. What makes it worth a second glance is what remains of its decoration: an elaborate cross framed by two lightly incised circles, with trefoils worked into both arms and the cantons, the corner spaces formed between the arms of the cross and its enclosing frame. The carving is so faint that the scholar R.A.S. Macalister, writing in 1916 to 1917, described the lines as no broader than pencil scribings.

Macalister classified the piece as eighth-century in type, placing it within the early Christian period when Inishcaltra, known in Irish as Inis Celtra or Holy Island, was a significant monastic site. The slab sits inside the nave of St. Caimin's church, set down against the north wall roughly four metres from the west gable. Macalister also noted that its cross design closely resembles several other slabs found at the same site, suggesting a local workshop tradition or at least a shared visual vocabulary among the craftspeople who produced devotional stonework there. The trefoil ornament, a three-lobed motif sometimes associated with Trinitarian symbolism in early Christian art, gives this particular slab a slightly more elaborate character than its plainer neighbours, even if that distinction is now almost invisible to the naked eye.