The stone is a cross-slab, a category of early medieval Irish monument in which a cross is carved in relief or incised directly onto a flat slab rather than cut free-standing. This one measures just over a metre in height and carries, across its upper face, a two-line ringed cross with a central circle and straight-ended terminals, except at the base, where the arm loops back on itself. More striking still is the inscription carved above the cross in two lines of early Irish script: OROIT DO CORMACAN, meaning "Pray for Cormacán". Someone, at some point, wanted Cormacán remembered.

The slab came to wider scholarly attention through George Petrie and Margaret Stokes, who published it in their 1872 collection of Christian inscriptions in the Irish language. Their illustration was based on a rubbing taken in 1869 by the Reverend James Graves, who found the stone among the ruins of the church on Inisbofin, the island in Lough Ree on the Roscommon and Westmeath border. By the time the antiquarian R.A.S. Macalister examined it in 1912, the slab had fractured into three pieces, and the fracture had already claimed two letters from the inscription, the opening O of OROIT and the C of CORMACAN, both reconstructed from the earlier rubbing. The stone has since been repaired, though it no longer sits on the island where it was carved, or even in the county where it was found. Its current address, a storage depot in Co. Galway, is a practical rather than poetic outcome for an object that was made to invoke prayer for a named individual across whatever centuries followed.