- Kays Curling in Scotland supplies Olympic curling stones using Ailsa Craig granite.
- The stones' body uses common green granite; the running band uses blue horn.
- The only exception was 2002, when Canada Curling Stone Company supplied stones with Welsh Trefor granite for the Games.
CORTINA D'AMPEZZO, Italy — One company in Scotland seems to maintain a stronghold on the curling stone supply chain, but there may be good reason for it.
Mark Callan, chief ice technician for curling at the Olympics, is also the former director of that Scottish company, Kays Curling.
He said the granite comes from the small island of Ailsa Craig, because of its unusual density. The makers take rocks from opposite ends of the island to put the pieces together.
"Half the island is Ailsa Craig common green, which makes up the body of a curling stone," Callan explained. "And the other half of the island is Ailsa Craig blue horn, which is largely waterproof, which makes it ideal for sitting on the ice."
The second of the two granites is the more dense variety, which makes up the thin, round running band on the bottom that sits on the ice, and the striking band around the middle.
"It's very good for absorbing impact. It it does that very, very well and over a long period of time without any noticeable damage," Callan said. "The running band of it is ideal because it sits on ice, and it doesn't absorb water. If it was to absorb water, the water would then freeze and expand, and then that would lead to the failure of the stone."
The remaining body of the stone comes from the other end of the island.
"The mating of the two granites together is really quite a match made in heaven," Callan said.
The dense granite found on Ailsa Craig is rare, but there are other sources. While Kays Curling has maintained an exclusive agreement with World Curling and the Olympics, the company did face a bit of competition in 2002.
During the Winter Games in Salt Lake City, curling stones were instead supplied by the Canada Curling Stone Company, which makes its stones from Trefor granite that comes from a quarry in Wales.
Callan said Kays Curling secured its now long-standing deal by the next Olympic Games. He added that the company has a contract with the owners of Ailsa Craig to keep mining the island through 2050. He said there are plenty of materials to keep the sport going for a very long time.
"You would be mining there or extracting granite for hundreds and hundreds of years, and you wouldn't really make a dent in it because the whole island is granite," Callan said.
