The carvings, concentric circles, nested arcs, oval forms, and parallel vertical lines, are classic passage tomb art, the kind of abstract geometric decoration most commonly associated with the great Neolithic chambered tombs of the Boyne Valley. That this motif vocabulary appears here, worked into an orthostat within a stone circle rather than the interior of a passage tomb, is what makes the discovery so quietly remarkable. The carving was not spotted by a professional excavation or a scheduled survey; it was identified by Ken Williams, and recorded in detail sufficient to establish it as only the second example of passage tomb art found anywhere in Munster.

The stone in question was catalogued as Stone No. 9 by the archaeologist Seán P. Ó Ríordáin in his 1951 plan of the circle, though no carving was noted at that time. It sits on the north-east side of the internal kerbing, four stones to the west of the cobbled entrance gap on the east of the monument. Three faces carry the decoration, while the fourth, the flat south-western face directed inward toward the centre of the circle, appears to have been deliberately split, leaving a surface quite unlike the rounded, carved faces. The largest carved face, the north-eastern, shows concentric circles roughly 12cm and 22cm in diameter, with indications of a partial third ring, accompanied by smaller oval and U-shapes above and below. The carvings continue around the north and south edges of the stone, though some are now heavily weathered and partly obscured by moss. Crucially, the engravings are truncated by the earthen bank that the orthostats face, which suggests the stone was carved before the bank was built up around it, or that the stone was reused from an earlier context altogether. The only comparable Munster example was found around 1880 in the townland of Croha West on Clear Island, Co. Cork, and is thought to have originated from the nearby Killickaforavane passage tomb.

The Grange stone circle, designated National Monument No. 247, sits in grassland on a low rise roughly 350 metres west of Lough Gur, itself one of the most densely monument-rich lake landscapes in Ireland. The circle is not isolated; within a few hundred metres lie two further stone circles, a possible portal tomb, a site known locally as the Giant's Grave, a standing stone site called Cloch á Bhíle, and a stone setting that may represent the remains of a court tomb. The decorated stone is accessible as part of a visit to the Grange circle itself, though locating the specific orthostat requires attention; count four stones west from the eastern entrance. For those unable to visit in person, a 3D model of the carved stone is available online at skfb.ly/oxs6R, which renders the surface detail with a clarity that even favourable raking light on the ground might not always provide.