It is a cross base, the lower portion of what was once a free-standing stone cross, and what makes it quietly interesting is the gap between its modest dimensions and the weight of its implied history. The block measures just 31 centimetres high and 24 centimetres wide, yet it carries a wide, deep rectangular socket cut centrally into its upper face, the kind of socket designed to hold a substantial upright shaft, now long gone.

The stone was recorded early in the twentieth century by R. A. S. Macalister, the Irish archaeologist whose systematic surveys of early Christian monuments documented many objects that might otherwise have gone unnoticed. He noted it in 1916 to 1917 at the north wall of the nave of St. Caimin's church, one of several early ecclesiastical structures on Inis Cealtra. The island itself was an important monastic site associated with St. Caimin, a seventh-century figure, and it attracted considerable religious activity through the early medieval period. The sandstone block has deep natural striations running across its surface, grooves formed by the character of the stone itself rather than by any carving hand, which gives it a slightly ambiguous appearance at first glance, somewhere between worked and raw material. At some point after Macalister's documentation, the base was moved from the church wall to the OPW chalet on the island, where it is now held.