A single curling stone certified for the Olympics costs over $600. That makes a full set of 16 stones worth $9,600. Since 2006, every stone used in the Olympic Winter Games has come from Kays of Scotland. The company has produced curling stones since 1851. But making these stones isn't easy. For every stone it makes, Kays uses granite from one tiny island off the coast of Scotland called Ailsa Craig. By combining Ailsa Craig's common green and blue hone granites, Kays produces the only stones al