It is easy to overlook, but the object repays attention. Trapezoidal in shape and modest in size, measuring a maximum of 25 centimetres long and 19 centimetres wide, it bears a shallow rectangular slot cut into its centre, with the sides of the socket angled inward. That socket, only a centimetre deep, would once have held the base of a cross, most likely a small free-standing one of the kind associated with early Irish monastic sites.

Inis Cealtra, sometimes called Holy Island, carries a long history of religious activity. A monastery was founded there, according to tradition, in the sixth century, and the island retains the remains of several early medieval churches, a round tower, and various grave slabs and cross-inscribed stones. The little socketed stone fits into that broader context of early Christian material culture, where portable or semi-portable stone bases were used to anchor processional or devotional crosses. Its current home inside the chalet, maintained by the Office of Public Works, keeps it sheltered from the weathering that has worn down so many comparable fragments elsewhere.