Measuring roughly 17.5 centimetres high and 21 centimetres wide, it is only a portion of a larger slab whose original shape is no longer known. What survives is enough to make it quietly remarkable: incised on its face is a linear equal-armed cross with expanded, forked terminals, and below that, the remnant of a single horizontal line of text, interrupted mid-sentence by the lower arm of the cross itself. The inscription is incomplete, its meaning now beyond recovery, but the relationship between the carved cross and the lettering gives the stone an unusual, almost compositional quality.

The fragment came to light during an excavation in 1944, recorded by Duignan and subsequently noted by Macalister. Its survival depends on the fact that it was built into the church wall rather than left exposed, which is both its preservation and its limitation; only one face is visible, and the stone's full thickness cannot be assessed. Scholars Okasha and Forsyth, writing in 2001, catalogued it as Toureen Peacaun 18, placing it within a wider tradition of early medieval inscribed stones from Ireland. Such slabs, typically associated with monastic or ecclesiastical sites, were often used as grave markers or devotional objects, and the combination of a cross with an inscription suggests this one carried some commemorative or dedicatory function, even if the words themselves are now lost.