It is a modest object by any measure, just 69 centimetres long and 26 centimetres wide, yet the rounded base of its shaft tells you something significant about its original purpose: it was designed to be driven into the ground, most likely marking a grave on the slopes of Kilmashogue mountain, where a church once stood and has since entirely vanished.

The slab's circular head carries a Greek double-line cross set within a circle, a form common to early medieval Irish stone carving, in which the cross arms are of equal length rather than elongated as in the Latin tradition. The shaft below is decorated with a square motif. F. E. Ball, writing in 1906, noted the existence of a church on Kilmashogue mountain, though by 1912, when Weston St. John Joyce published his Neighbourhood of Dublin, no physical trace of the building remained. The graveslab was presumably removed for safekeeping at some point in that interval, or perhaps earlier, finding its way to the St. Columba's College chapel where it has been recorded and studied since.

St. Columba's College is a boarding school on the Whitechurch Road in Rathfarnham, on the southern fringes of Dublin city, with Kilmashogue itself rising into the Dublin Mountains nearby. Access to the chapel and its contents would depend on the college's own arrangements, so it is worth enquiring in advance rather than arriving without notice. The slab is a small thing to seek out, easy to overlook in a chapel setting, but the detail repays close attention: the clean geometry of the cross within its circle, the deliberate shaping of the base, and the knowledge that the church it once accompanied has left no mark at all on the hillside above.