It measures just over a metre tall, and its cross form is created not by carving in relief but by cutting four deep notches into the edges of the stone. Two of those notches, on the lower left and upper right of the western face, do not pass all the way through, which has led researchers to suggest the piece may never have been finished. There is no other decoration. The stone is much weathered, and the question of what its maker intended has no certain answer.

The slab was not found standing. It came to light among debris within the early medieval monastic enclosure on High Island, a site associated with a community of monks who chose this remote, wave-battered island precisely for its isolation. A leacht is a low, rectangular cairn or platform of stones used in early Irish monasticism as a focus for prayer or commemoration, and it was onto one of these that the slab was placed upright in 1869, following its recovery by Kinahan, who documented it that same year. A second cross-slab was found in the same debris, suggesting that at least some of the enclosure's stone furnishings had been disturbed or collapsed well before any formal investigation took place. By the time Fisher and colleagues recorded the site in 2014, the slab had shifted again and was leaning against the leacht rather than standing on it, a small sign of how difficult it is to stabilise anything on an island exposed to Atlantic weather.