The stone at Knockduff is a curiosity not because of what survives, but because of what was deliberately put out of sight. Around 1985, it was removed from the level pasture where it had stood for centuries and buried in a nearby quarry to the north, apparently along with two other standing stones from the same general area. It does not appear on the Ordnance Survey six-inch maps of 1842 or 1904, which suggests it was either overlooked by surveyors or considered too modest to record. Whatever the reason for that earlier omission, its subsequent disappearance underground is a sharper kind of loss.

A 1937 account, cited by a researcher named Broker, may describe this same stone when it stood on land belonging to a John Keeffe. At that point it was modest in scale, roughly two feet high with a girth of about three feet, the kind of upright prehistoric marker that punctuated the Irish landscape in considerable numbers before agricultural improvement removed so many of them. What makes the Broker reference quietly affecting is the detail that accompanied it: the old people, he noted, would not allow the stone to be interfered with. That informal protection held for decades, sustained by local deference to something older than living memory. Within fifty years of that observation being written down, the stone was gone. Standing stones as a class are among the most enigmatic prehistoric survivals in Ireland, typically dating from the Bronze Age, erected for purposes that remain unclear, whether as boundary markers, ritual sites, or memorials. This one now exists mainly as an absence, documented only in a brief paragraph and a recalled prohibition.