Its back and sides are rough and entirely unworked, and it tapers to a point at the top, giving it a shape more accidental than architectural. Yet its face is another matter entirely, carved with a Latin cross, a circular expansion at the centre filled with a spiral pattern, and semicircular terminal expansions containing neat key-patterns. The contrast between the raw, irregular stone and its precisely decorated front face gives the object an almost provisional quality, as though the carver cared only for the surface that would be seen.

The scholar R.A.S. Macalister examined and recorded the slab in 1916 and 1917, cataloguing it as being of tenth-century type. At that time it measured roughly three feet nine inches by two feet six inches. What caught Macalister's attention beyond the carving itself was how closely the design resembled work associated with Clonmacnoise, the great monastic settlement on the Shannon in County Offaly, and he suggested it may actually have been produced by a Clonmacnoise artist working in or supplying this Clare island community. A cross-slab, to give the term its plain meaning, is simply a flat stone bearing a carved cross, often used as a grave marker or devotional object in early medieval Irish monasticism. That this one carries the stylistic fingerprints of a workshop some distance away hints at the networks of craft and influence that connected island communities like Inishcaltra to the wider monastic world during the early medieval period.