Blarney Stone
The Blarney Stone is said to be a piece of the Stone of Destiny, which Robert the Bruce gave to his Irish ally, Cormac Maccarthy, following the Battle of Bannockburn.
History
Cormac's descendants placed the Stone in Blarney Castle. According to legend, it is supposed to bestow "the gift of gab" on whoever kisses it. (Shari claims to have been one of those who kissed it.)