<P> The granite for the stones comes from two sources: Ailsa Craig, an island off the Ayrshire coast of Scotland, and the Trefor Granite Quarry in Wales . </P> <P> Ailsa Craig is the traditional source and produces two types of granite, Blue Hone and Ailsa Craig Common Green . Blue Hone has very low water absorption, which prevents the action of repeatedly freezing water from eroding the stone . Ailsa Craig Common Green is a lesser quality granite than Blue Hone . In the past, most curling stones were made from Blue Hone but the island is now a wildlife reserve and the quarry is restricted by environmental conditions that exclude blasting . </P> <P> Kays of Scotland has been making curling stones in Mauchline, Ayrshire, since 1851 and has the exclusive rights to the Ailsa Craig granite, granted by the Marquess of Ailsa, whose family has owned the island since 1560 . According to the 1881 Census, Andrew Kay employed 30 people in his curling stone factory in Mauchline . The last harvest of Ailsa Craig granite by Kays took place in 2013, after a hiatus of 11 years; 2,000 tons were harvested, sufficient to fill anticipated orders through at least 2020 . Kays have been involved in providing curling stones for the Winter Olympics since Chamonix in 1924 and has been the exclusive manufacturer of curling stones for the Olympics since the 2006 Winter Olympics . </P> <P> Trefor granite comes from the Yr Eifl or Trefor Granite Quarry in the village of Trefor on the north coast of the Llŷn Peninsula in Gwynedd, Wales and has produced granite since 1850 . Trefor granite comes in shades of pink, blue and grey . The quarry supplies curling stone granite exclusively to the Canadian, Canada Curling Stone Co., which has been producing stones since 1992 and supplied the stones for the 2002 Winter Olympics . </P>

Who makes the curling stones for the winter olympics