The Blarney Stone (Irish: Cloch na Blarnan) is a block of Carboniferous limestone built into the battlements of Blarney Castle, Blarney, about 8 kilometres (5 miles) from Cork, Ireland. According to legend, kissing the stone endows the kisser with the gift of the gab (great eloquence or skill at flattery). The stone was set into a tower of the castle in 1446. The castle is a popular tourist site in Ireland, attracting visitors from all over the world to kiss the stone and tour the castle and its gardens.

Carboniferous Limestone is a collective term for the succession of limestones occurring widely throughout Great Britain and Ireland that were deposited during the Dinantian Epoch of the Carboniferous Period. These rocks formed between 363 and 325 million years ago. Within England and Wales, the entire limestone succession, which includes subordinate mudstones and some thin sandstones, is known as the Carboniferous Limestone Supergroup.

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