From Scottish Rock to Olympic Ice

Like millions around the world, I have spent the last few weeks glued to the TV watching the Winter Olympics. Under Milan and Cortina’s vibrant beauty, the Games deliver world-leading winter sport talent, leaving me on the edge of my seat, wondering: will she land that jump? How fast can he skate? One sport in particular stood out — curling, where players slide stones across ice towards a target whilst using a broom to sweep and control their speed. However, curling equipment has a unique backstory: every stone originates in Ailsa Craig, a tiny uninhabited volcanic island in the Firth of Clyde on the West Coast of Scotland.

Commonly referred to as ‘chess on ice,’ curling originated in sixteenth century Scotland. It followed Scottish emigrants to Canada, ultimately making its Olympic debut in 1924. The competition stones retain this strong Scottish history, with the Kays Scotland factory serving as the Olympics’ exclusive supplier. The stones’ body is carved from microgranite found only on Ailsa Craig, whose rare geological properties make it uniquely suited to curling. It is magma, or molten raw material from which all indigenous rocks form, that cools more quickly, producing a granite that is significantly denser than usual. This makes the finished stone exceptionally tough, built to withstand constant sliding across ice and the heavy collisions between stones. With a unique hard mineral composition of around 65-80% feldspar and up to 25% quartz, the final curling stones can withstand daily use without scratching or damaging the exterior. The granite has no crustal contamination due to its tight, interlocking structure, free of weaker minerals, resulting in an exceptionally pure and dense rock.

After sourcing the stone, the Kays factory cuts and shapes it into its final form. The stone's body is cut from a single piece of green granite with high elasticity, allowing it to absorb and release energy on impact in a spring-like motion and preventing the stone from cracking in play. The running band at the bottom of the stone is cut from blue honed granite, whose tight molecular structure makes it naturally waterproof — essential for preventing wear as the stone travels along the ice. In the factory, the two granite pieces are precisely cut, shaped, and polished together before a central hole is drilled for the handle, completing the perfect curling stone fit for Olympic standards.

However, sourcing and producing the final curling stones is a far more complex journey than it appears. Ailsa Craig is a Special Protection Area (SPA) site, strictly safeguarded by various European wildlife bodies for its vital habitat of rare and migratory birds. Consequently, all granite harvesting by Kays must follow strict environmental legislation to protect the island’s wildlife. The extraction is restricted to winter months, roughly September to November, to avoid the bird breeding season, with a designated ecologist accompanying the Kays team to ensure no harm to the population. For this year’s Olympic Games, around 132 stones, each weighing around 18kg, were required. Therefore, for the Kays team, preparing and collecting granite for Milan had to be a highly efficient and precise operation — gathering enough top-quality stone to meet high international demand in time for the Games in February. The undertaking is no small feat, but Kays pulled it off.

“It’s not just robots and machines and automated tools doing it. It’s handcrafted, it’s traditional, it’s got history. It’s a great wee place,” said Ricky English, operations manager at Kays Scotland, demonstrating the pride of the Kays team as they carry forward their long tradition of crafting world-class curling stones. From Vancouver to Sochi and now Milan, these stones carry a piece of Scotland with them wherever the Games go.

Illustration by Isabelle Holloway