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Curling stones no longer taken for granite

Study challenges long-standing thoughts on manufacturing of curling stones.

(March 14, 2022) - Curling is a popular winter sport that originated in 16th century Scotland and was brought to Canada by the Scottish Highlanders. Since then, Canada has dominated in curling, having medalled in nearly every Olympics. At the most recent Olympic Winter games that took place in Beijing, China from February 4-20, 2022, the Canadian men’s curling team defeated the United States to take home the bronze medal. 

Curling involves sliding cylindrical stones across a sheet of ice. The stones used for international competition come from only two locations: either Ailsa Craig, a rocky isle off the western coast of Scotland, or the Trefor quarry in North Wales. But are these rocks unique? Could curling stones be made from other locations?

In the first study of its kind since 1890, these questions were addressed by Laurentian University PhD Mineral Deposits and Precambrian Geology student, Derek Leung. An article based on Leung’s undergraduate thesis was recently published in The Canadian Mineralogist, co-authored with supervisor Dr. Andrew McDonald, Professor of Mineralogy and Director of the Microanalytical Centre at Laurentian’s Harquail School of Earth Sciences. The study was supported by a scholarship from the Society of Economic Geologists Canada Foundation, with fieldwork supported by the Mykura Fund from the Edinburgh Geological Society. Leung is also a recent recipient of a prestigious NSERC PGS-D scholarship

The team from Laurentian University used modern analytical techniques to probe the mineralogical makeup of the rocks. They found that curling stones belong to a group of granite-like rocks known as granitoids. Additionally, the curling stones share some common characteristics, but none of these geological characteristics can be considered unique to curling stones. This opens the door to the manufacture of the same from materials in other locations, perhaps even from materials right in our backyard, in Sudbury, Ontario. 

About the study’s findings, Leung said as follows: “I’ve always wondered what curling stones are made of. This study lays out the groundwork for future research on curling stones, such as linking rock textures to the curling motion of a stone, which is a controversial topic among scientists and the curling community.”

Dr. Andrew McDonald added: "Curling is part of our Canadian DNA, so it's most apt that a high quality, cutting-edge study into the geological and mineralogical makeup of curling stones should be at a Canadian institute and what better place than the Harquail School of Earth Sciences.”