The piece is the head of a round-arched window light, a single stone forming the top of a window opening, measuring roughly 43 centimetres across and 33 centimetres high. What makes it more than a routine find are the spandrels, the triangular spaces between the curve of the arch and the square frame around it. Here, those spaces are not left plain or given simple decorative moulding. Instead, they are carved with primitive human heads, each about 12 centimetres by 10 centimetres, sunken into the stone surface, with the edges of the arch chamfered, meaning cut at an angle to soften the corner.

Carved human heads of this kind appear occasionally in Irish medieval ecclesiastical stonework, sometimes interpreted as apotropaic figures, intended to ward off harm, and sometimes as simple decorative convention whose original meaning is now difficult to recover. The word "primitive" in the original description is a technical rather than a dismissive term, referring to a directness of carving style rather than any judgement about skill. The fragment was associated with a church site at Newberry, and its discovery during conversion work suggests the building was being adapted for a new use at the time, with the carved stone coming to light in the process rather than being deliberately excavated. Beyond the dimensions and the description of those small, carved faces, the fragment's precise date and the full history of the church it came from are not documented in the surviving record.