What makes it quietly remarkable is the symbol carved into its face: a Chi-Rho, one of the earliest Christian monograms, formed from the first two letters of "Christ" in Greek and used by early medieval communities to mark the graves of their dead. The incision is described as fine, suggesting a craftsperson working with care on an object intended to endure.

The stone originated on Inis Cealtra, the island monastery in Lough Derg known in English as Holy Island, where it was associated with St Brigid's church. It came to light through the collapse of a wall near that church, the kind of slow structural failure that frequently exposes objects long embedded in early medieval masonry. Inis Cealtra was a significant ecclesiastical settlement, and gravemarkers of this type, modest in scale but deliberate in their decoration, were a common feature of such sites across early Christian Ireland. The Chi-Rho had largely given way to the ringed cross form by the later medieval period, which suggests this stone belongs to an earlier tradition of commemorative carving, though the notes do not specify a precise date.