Set flush into the floor, it measures 1.78 metres long and 0.75 metres wide, and its surface carries an incised eight-armed cross rising from a stepped base, with a marginal inscription in Gothic lettering running along its edges. The slab is a graveslab, a funerary monument of a type common in medieval Ireland, where carved stone slabs were placed directly over, or in the vicinity of, a burial as a permanent marker of identity and status.

The inscription commemorates one Johannes Burnell of Balgriffin, a name that places him within the medieval Anglo-Norman community that shaped much of Dublin's ecclesiastical and civic life. Balgriffin is a townland on the northern fringe of County Dublin, and the Burnell family were among the prominent Anglo-Norman settler families of the region. That a member of this family should have a graveslab installed in St Audeon's, on the south side of the city near the old walls, speaks to the patterns of patronage and piety that connected outlying landholders to urban churches in medieval Ireland. The eight-armed cross, sometimes called a cross of arcs or wheel-like cross, was a design choice with its own symbolic weight, distinct from the more familiar Latin or Celtic cross forms. Gothic marginal inscriptions of this kind typically followed a formulaic Latin phrasing asking for prayers for the soul of the named individual, though the precise wording here is not fully recorded in the available notes.

St Audeon's stands on Cornmarket, off High Street in the Liberties area of Dublin, and the medieval fabric of the church, including its tower, is maintained by the Office of Public Works and open to visitors during the summer season. The graveslab sits in the tower floor, which means it is encountered almost immediately upon entering that section of the building. It is worth pausing to crouch or kneel to trace the incised lines, as the carving is shallow and can be difficult to read in certain light. Early morning visits, when light angles more directly through the tower openings, tend to make the inscription and cross design easier to pick out.