All the curling stones being used at the Pyeongchang Winter Games are made from granite mined from the tiny, uninhabited island of Ailsa Craig, in the outer Firth of Clyde. The granite is worked into the final stones by staff at Kays Curling in Mauchline, 40 miles from Ailsa Craig on the mainland. Kays has been producing top-level curling stones for more than a century. Though participation in the sport is declining in the UK, the factory is producing more stones than ever to ship overseas. In 1998 – the year the sport was given medal status at the Winter Olympics – 36 countries played the sport; today, there are 54 countries competing worldwide