Prior to the foundation of Kays of Scotland, there was little regulation to the sport of curling and stones of any shape or size were used. Through a process of elimination, stones from Ailsa Craig were found to be highly resistant to splintering, making them desirable for this purpose.[6][7]
In 1851, William Kay and sons Andrew and Thomas created Kays of Mauchline, a workshop in Haugh, East Ayrshire, Scotland and later received permission from the family who owned the island of Ailsa Craig to harvest granite for the manufacture of curling stones.[7]
The company eventually found itself under the stewardship of Thomas Kay's wife's brother-in-law, James Wyllie, and has remained a business wholly owned by the Wyllie family. Descendant James "Jimmy" Wyllie currently owns the company.[8][9][10][11]