One face shows a plain Latin cross, as does its opposite. A third carries what appears to be a swastika motif, elongated and enclosed in a square so that it reads more as a cross than the symbol more familiar today. The fourth is the most elaborate: a Latin cross whose head and shaft each divide into triangular terminals, the junction of shaft and arms formed by a square, and the arms by equilateral triangles, each bisected into right angles. Running along one of the stone's angles, inverted with respect to all four crosses, is an ogham inscription. Ogham is an early medieval alphabet in which letters are represented by notches and strokes cut along a central stem line, most commonly the edge of a standing stone. This particular inscription is damaged and unclear in places; the scholar R.A.S. Macalister, working in 1945, read it tentatively as something close to (CO?)BB(A?) AVI VLATIAMI MAQ, a partial ancestral formula of the kind common to such inscriptions.

The stone originated not in Dublin but on Inis Mhic Aoibhleáin, known in English as Inishvickillane, a remote island off the tip of the Dingle Peninsula in Co. Kerry. It was found near St. Brendan's Oratory on the island, and when the antiquary John Windele first recorded it, it was lying in front of that small early Christian structure. By 1901 it had been repurposed as a lintel within the oratory itself. In 1902, it was removed to Trinity College Dublin, where it has remained ever since. The four crosses are thought to have been added after the ogham was cut, a conclusion drawn from the fact that they were carefully positioned so as not to obscure the existing inscription. That layering of script and symbol, early Christian imagery grafted onto an older commemorative text, reflects a pattern seen across early medieval Ireland, where new devotional forms were accommodated alongside, rather than simply replacing, what came before.