It measures just 1.3 metres long and 0.65 metres high, yet its surface is marked with three incised Latin crosses alongside two unusual motifs: linear grooves that widen at their ends into expansions edged with radial lines. These carvings identify it as a mass-rock, the kind of improvised outdoor altar used by Catholic communities during the Penal era, when the practice of the Roman Catholic faith was suppressed under a series of laws introduced in the late seventeenth and eighteenth centuries. With churches closed or seized and priests subject to arrest, congregations gathered in remote or inconspicuous spots, often around a suitably flat stone that could serve as an altar surface.

Resting against the south-east end of the boulder is a smaller, irregularly shaped companion stone, roughly 0.39 metres by 0.29 metres, with a hemispherical depression carved into it, about 0.08 metres across and 0.03 metres deep. A hollow of this kind is consistent with use as a vessel for holy water or for holding a candle during an outdoor ceremony, though the boulder and its attendant stone are documented simply by their physical description and carvings. The three crosses and the more enigmatic grooved motifs suggest that this was not a casual or temporary arrangement but a site used with some regularity and given deliberate, if plainly worked, sacred markers.