Cut roughly into shape, it measures just over half a metre above ground and carries along its south-western angle something that most visitors would walk past without a second glance: a series of horizontal scores, the remains of an ogham inscription. Ogham is an early medieval Irish script in which letters are represented by groups of notches or lines cut along the edge of a stone, typically reading upward. Here, roughly twelve scores survive within a space of about thirty centimetres, but weathering and spalling of the surface have left the text beyond any reasonable interpretation.

The scholar R. A. S. Macalister recorded the stone in 1945, placing it at that time outside the old cemetery at Newcastle rather than within the abbey interior, which suggests it has been moved at some point, or that the boundaries of the site have shifted in understanding or in fact. Its current setting inside the abbey connects it to a place that already has considerable age behind it, though the ogham tradition itself predates the medieval ecclesiastical landscape of Tipperary by several centuries. What is clear is that someone once thought it important enough to inscribe, and that the inscription almost certainly carried a name or a memorial formula, as was standard for ogham stones used in funerary contexts. Whether it began its life as a purpose-cut grave marker or was repurposed from an earlier standing stone is a question the damaged surface can no longer answer.