It is a font, the kind once used for baptism or the blessing of water, and it measures less than a metre across in any direction, 0.7 metres north to south, 0.65 east to west, and just 0.24 metres deep. Small, functional, and easy to walk past without a second glance. What makes the spot worth pausing at, though, is not the font itself but what was once found nearby and has since vanished entirely.

At some point in the nineteenth century, an inscribed pillar stone was discovered within the graveyard. It bore concentric circles, a decorative motif associated with prehistoric carving in Ireland, and it was recorded by O'Reilly in 1901, by Crawford in 1913, and again by Ó hÉailidhe in 1957. Each successive scholar noted its existence, yet by the time the site was formally recorded it had disappeared. Whether it was moved, buried, broken up, or simply absorbed into the fabric of the graveyard is unknown. Its loss is a minor but telling example of how many early inscribed stones were displaced or destroyed before systematic archaeological recording became standard practice. The graveyard also contains a circular cemetery watchtower to the west of the font, a structure of a type built in the early nineteenth century to deter bodysnatchers, who targeted Irish graveyards to supply dissecting rooms with cadavers at a time when legal supply of bodies for anatomy was extremely limited.

Cruagh graveyard is situated in the foothills south of Rathfarnham, and the site is accessible without great difficulty, though the surrounding area is part of the upland fringe and the ground can be uneven underfoot. The font sits to the north of the church remains, and the watchtower is visible to the west. Visitors interested in the lost pillar stone will find no trace of it, but the record of its concentric circle decoration is preserved across those three scholarly references, which is at least something. The graveyard rewards a slow circuit rather than a quick look.