At some point during Land Project work, ground-clearance and drainage operations that reshaped much of rural Ireland in the mid-twentieth century, the stone was turned up at a nearby enclosure site roughly 500 metres to the east. A local priest, by all accounts, had it relocated to the churchyard for safekeeping, which is how a prehistoric or early medieval ritual object came to rest in an unmistakably modern ecclesiastical setting.

The stone is a bullaun, a type found at early Christian sites and ancient enclosures across Ireland. The word refers to a boulder, usually of some considerable size, into which one or more cup-shaped hollows have been deliberately ground. Their precise function remains a matter of debate among archaeologists; they have been associated with early monastic activity, with water ritual, and with folk cures, and many continued in local religious use long after their original context had been forgotten. The Rathbaun example is substantial, measuring roughly 1.5 metres in length and just under a metre in height, with a broad, relatively flat upper surface. Into that surface, two hollows sit close together: one circular, about 33 centimetres across, the other slightly larger and oval in plan, measuring roughly 43 by 36 centimetres. Both are shallow, each cut to a depth of around 8 to 10 centimetres. The pairing of two hollows on a single stone is a recognised feature of the bullaun tradition, though whether the two were made at the same time or represent successive episodes of use is rarely possible to determine.

The stone can be found in the grounds of Rathduff church. Its original findspot, at the enclosure to the east, is the site properly associated with it in the archaeological record, but the boulder itself is accessible at the churchyard, where it has been settled for long enough that most locals now think of it as belonging there.