What makes it unusual is not its size but what someone, at some point, did to its upper end: the stone has been roughly worked into the suggestion of a ringed cross, the kind of circular-headed cross form associated with early Christian Ireland. The operative word is roughly. This is not fine carving. The circle, about 40 centimetres in diameter, is implied rather than precisely cut, and the top of the stone projects a few centimetres above it, as though the mason either ran out of patience or never intended anything more polished than this. The north side of the upper portion has since been damaged, which softens the outline further.

The stone was recorded by Mould in 1963 and measures 1.19 metres in height, 0.43 metres across, and 0.15 metres deep, oriented with its long axis running north to south. A ringed cross, sometimes called a Celtic cross, combines a Latin cross with a surrounding circle, a form that appears widely across early medieval Irish ecclesiastical sites, usually in cut stone slabs or free-standing high crosses of considerably more ambition than this example. The Ballymacrown stone occupies a different register entirely: modest, local, and shaped just enough to signal its intention. Whether it marked a grave, served a devotional purpose within the burial ground, or was adapted from an earlier plain standing stone is not recorded.