Nearly two metres long and chamfered, meaning bevelled, along each edge, it carries no inscription, no name, no date. What it does carry is a carefully incised cross running almost the full length of the stone, its design precise enough to suggest a craftsman working to a clear programme, yet anonymous enough to have kept its secrets for centuries.

The decoration repays close attention. The cross-head is equal-armed with curved angles and enclosed within a circle that rests directly on the shaft, a form sometimes called a ringed or wheel cross. In the upper angles of the cross-head are curvilinear motifs, now poorly preserved, while the lower angles contain quatrefoils, four-lobed geometric forms common in medieval stonework. A circular knop, a small rounded protrusion, sits just below the cross-head where the shaft begins, and the shaft itself terminates in a further quatrefoil. Maher, writing in 1997, noted no evidence that the stone ever bore an inscription, which means whoever commissioned it either chose imagery over text or simply could not be identified by name. The slab itself measures 1.93 metres in length and tapers from 0.6 metres wide at the top to 0.43 metres at the base, and it carries three slight cracks across its face. Its position in the chancel is specific: six metres from the east gable and 3.3 metres from the south wall, placing it well within the most sacred part of the church, the area reserved for the high altar and, in an Augustinian house such as this, typically off-limits to ordinary burial. Whoever lies beneath it held some standing in the community at Athassel, even if that standing has long since been forgotten.