Lesley Andrews gave a most interesting talk on Scottish curling stones. I thought curling was a Scottish winter game played by village yokels. I was wrong! It has had Winter Olympic status since 1998. The game consists of two teams of four players each, with eight stones between them, and the idea is to slide the stone, which turns, hence the name curling, towards a target called a button. Rather like a game of bowls on ice. The origin of the game goes back into obscurity, but the oldest known curling stone is dated back to 1510. The stone is quarried from the island of Ailsa Craig, just off the southern coast of Ayrshire in the Firth of Clyde in western Scotland. The stone is ferried across to the harbour of Girvan, and taken to the factory at Mauchline, inland.

Sitting in the Firth of Clyde the profile of Ailsa Craig is easily recognised when viewed from the Ayrshire coast. Approximately 10 miles from Girvan it is nearly two miles in circumference and rises to 338 m. The island was formed as a result of intense volcanic activity 60 million years ago.

The island is geologically interesting, having a pale, greenish microgranite called “ailsite”, from which the curling stones are made. There are prominent jointed columns, of what seem to be dolerite sills on the island which is about 1,3 km across. The stone has been quarried from about 1750. It contains quartz, Na and K feldspars, riebeckite, aegerine, and aenigmatite. No micas, sulphides or clay minerals are present, making the rock tough and compact.

The rock is lathe-turned into a large bun-shaped curling stone, weighing 17–20 kg. A coloured, durable plastic handle is attached to each stone. The stones are highly polished, with an “equator” band sand-blasted onto the stone, called the striking band, to knock other stones out of the way when skimmed along an icy surface. There is also a narrow running band made from an insert of Blue Hone granite (also from the island) on the bottom of the stone where it touches the ice. There are fears about the future of the Ailsa Craig quarries, as no more blasting can take place because the island has been declared a sea bird nature reserve since 2004. Loose rock can still be collected. Welsh Trefor granite, or some other similar igneous rock may have to be used in the future. Experiments are afoot about using a porcelain ceramic, called “ailset” after the island. Lesley brought a selection of souvenirs made from the Ailsa Craig microgranite, including miniature curling stones, earrings, and “ice blocks” – you put the ice blocks in the freezer to get cold and pop them in a glass of your favourite blend of whisky which then doesn’t get diluted, as it does by normal ice.

The talk was illustrated by a slide show and video clips. These ended with an amusing, kitch, architectural masterpiece of a pizza outlet somewhere in Canada, built to resemble a giant curling stone. I think all who attended this meeting found Lesley’s talk fascinating. I hate games of all kinds, but I thoroughly enjoyed every moment of the talk, including clips of seeing the game played. It was a great meeting. TVJ

Credits: The Ailsa Craig photo is by Davie Law, 2005, and the curling stone one is from a Kays of Scotland website.

 If you wish to learn more about curling, try the website   www.worldcurling.org.