It is not an especially large stone, tapering from roughly 46 centimetres wide at the top to 33 centimetres at the base, but the carving on its face rewards close attention. Incised into the surface is a circular cross-head formed by two concentric lines that push outward into three short rectangular arms pointing north, east, and west. Below it, the shaft is defined by three vertical lines running in parallel bands down the stone. The base of the cross disappears into the soil, and the shouldered top of the slab, which once had a raised central piece, is now broken. A grooved border follows both sides of the front face, continues along the top, and turns up into that missing raised section, so the decoration effectively outlines a shape that is no longer fully there.

What makes the slab particularly interesting is that it does not stand alone in any meaningful sense. Approximately one kilometre to the south-west, across the Clashawley River, the medieval graveyard of Kiltinan contains two graveslabs of closely similar design. At Kiltinan the situation is reversed: the cross-heads are buried beneath the ground and only the shafts and bases are visible, whereas at Coolmundry the cross-head is exposed and the base is hidden. Taken together, the three slabs share enough in decorative style, including the incised concentric circle cross-head and the bordered shaft treatment, to suggest they were produced within the same local tradition, possibly by the same workshop or by craftsmen working from a common model. Scholars have placed this decorative style in the thirteenth or fourteenth century, a period when such incised graveslabs, cut into the flat face of a prepared stone rather than carved in relief, were a common form of commemorative marker across much of Ireland. The Coolmundry slab now sits within the grounds of Grove Estate, its ecclesiastical setting long disused but the stone itself remaining in place, still marking whoever it was set here to remember.