It measures roughly 27 centimetres high and 46 centimetres wide, barely larger than a sheet of paper, yet its visible face holds two complete horizontal lines of text and, above them, two small incised Latin crosses with expanded terminals, meaning the arms of each cross flare outward slightly at their ends, a decorative flourish common in early medieval stonework. The stone is substantially complete, though its lower edge is damaged and its bottom right corner is missing.

The slab came to light during an excavation at the site in 1944, documented by Duignan and later by Macalister in 1949. It belongs to a category of early Christian carved and inscribed stones that were produced in Ireland roughly between the sixth and twelfth centuries, often associated with monastic sites and used to mark burials or commemorate individuals. St Peakaun's itself is the kind of modest early ecclesiastical enclosure that dots the Tipperary landscape, its name preserving the memory of a local saint largely unknown outside the immediate area. The stone was subsequently built into the east wall of the church interior, where it has remained, catalogued by scholars Okasha and Forsyth in their 2001 study of early medieval inscriptions in Ireland.