A Bit Of St. Patrick’s Day Skepticism

by | March 17, 2014

St. Patrick’s Day has some religious significance, according to the Catholic Church, but for the vast majority of celebrants it seems to be much more about wearing some green, raising a pint or two of stout to the Emerald Isle, and perhaps listening to a bit of nice traditional(ish) music. I’m between the stout and the Jameson’s, which seems like a good time to note that some geologists at University of Glasgow’s Hunterian Museum took St. Patrick’s Day to also be a suitable occasion for skepticism.

The scientists have analysed a sample taken in the middle of the 19th Century from Cloch na Blarnan, the Blarney Stone, a specific piece of rock set into the walls of Blarney Castle in Ireland. Improbable stories surround the Stone’s provenance, and it supposedly confers the gift of eloquence on anyone who kisses it.

For centuries, legends have abounded about the origins of the stone, which some have claimed was hewn from Stonehenge or sent over as a gift from the Scots by Robert the Bruce after victory at the battle of Bannockburn in 1314. But the secret of the stone has been unravelled after the discovery of a unique 19th-century microscopic slide taken from the rock at Blarney Castle, near Cork.


Geologists at the University of Glasgow’s Hunterian Museum can reveal the true nature of the Stone after studying the historic microscope slide, containing a slice of the stone ground so thin that it is transparent to light. Their analysis indicates the Blarney is a limestone, made of the mineral calcite, and containing recrystallised and slightly deformed fragments of fossil brachiopod shells and bryozoans – all of which are unique to the region where it is based.


Dr John Faithfull, curator at the Hunterian museum, said: “This strongly supports views that the stone is made of local carboniferous limestone, about 330m years old, and indicates that it has nothing to do with the Stonehenge bluestones, or the sandstone of the current ‘Stone of Destiny’, now in Edinburgh Castle.”

No surprises there, but it’s good to have the Stone’s origins straightened out. I can enjoy and appreciate the rich folklore surrounding Cloch na Blarnan without having to convince myself that it’s a misplaced chunk of Stonehenge, or that kissing it would make me into a brilliant public speaker.


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