The slab sits just over three metres east of the north-east corner of the Priest's House, a small Romanesque building that itself tends to draw the eye. But the slab beside it carries its own puzzle: roughly rectangular, cut from mica schist, a metamorphic rock with a faintly glittering surface, it measures just over 1.3 metres in length and about 56 centimetres wide. What makes it curious is the way it was made. The upper 0.9 metres has been carefully squared and dressed smooth, while the lower section was left comparatively rough and unfinished.

Patrick Healy, who catalogued it in an unpublished Office of Public Works survey of ancient monuments at Glendalough in 1972, noted a narrow groove running down one edge, roughly 2 centimetres wide and 2 centimetres deep, extending 84 centimetres down from the top of the slab. That detail is small but significant. Healy suggested the slab may have formed part of a composite structure, meaning it was likely never intended to function alone but was designed to slot or sit against another element, perhaps a kerb, a cover slab, or a framing piece of some kind. Whether that companion piece still exists somewhere nearby or has long since vanished is not recorded. The slab is catalogued simply as Healy's number 175, one entry in a long inventory of stones that Glendalough has accumulated over more than a millennium of use and partial abandonment.