THE distinctive greenish-grey hump of Ailsa Craig rises out of the sea, a familiar landmark for generations of childhood holidays.

While renowned for its thriving puffin and gannet colonies – and over the centuries a castle to protect from Spanish invaders and even a prison – the island off the Ayrshire coast from Girvan can equally claim its place within the crucible of sporting history.

This granite jewel in the Firth of Clyde is tied to a rich tradition stretching back hundreds of years – with two-thirds of the world’s curling stones said to originate from Ailsa Craig.

When Scotland plays host to the European Curling Championships this month, every single stone that glides across the ice at the Braehead Arena will have been borne from this craggy volcanic plug.

It is fitting that such a valuable resource should be found here: the first written reference to curling was recorded at Paisley Abbey in 1541. By the late 18th century, the game was widely played across the Lowlands and Robert Burns recounts curlers flocking to loughs in his poem Tam Samson’s Elegy, penned in 1786.

Granite quarried from Ailsa Craig is transformed into gleaming curling stones in the East Ayrshire town of Mauchline. It is here that Kays Curling has had its manufacturing base since 1851. Today, it is the official – and only – supplier to the World Curling Federation for top-level events, including the Olympic and Paralympic Games.

Away from the thud of machinery and thick film of white dust that swirls across the factory floor, director Mark Callan is explaining the “geological fluke” that makes Ailsa Craig granite unique and how the business of making curling stones has evolved.

“Things have changed markedly,” he reflects. “Around 150 years ago there were multiple companies in Scotland producing curling stones. These were largely attached to quarries with some in the Borders as well as places such as Stirling, Falkirk and further north.

“The biggest problem they had was that the quality of the granite was a bit suspect. What makes Ailsa Craig so special is that the granite is very low in quartz. It is the quartz in granite that is its weak point. Once you take quartz into a very cold or hostile environment like an ice rink, it becomes brittle and fragile. An impact can create fissures and cracks, the stone breaks and fails.

The Herald: Curling stones being made at Kays Curling in Mauchline, Ayrshire. Picture: Kirsty AndersonCurling stones being made at Kays Curling in Mauchline, Ayrshire. Picture: Kirsty Anderson

“The Ailsa Craig granite is a more open weave or structure with minimal quartz and it reacts well in a cold environment. The main body of the stone is made from what is called common green and the running surfaces are blue hone, a unique granite only found on Ailsa Craig.

“The blue hone is a closed cell construction so it is waterproof and doesn’t absorb moisture. This makes it ideal for sitting on ice. Every other granite has a certain porosity. If it absorbs water in an ice rink it will pit and crack and fail.”

It is a sentiment echoed by factory manager Bill Hunter. “Think of the beautiful granite buildings in Aberdeen,” he says. “They sparkle on a sunny day and that’s the problem: they are full of quartz. When two curling stones made from quartz rich granite hit together? They shatter.”

Kays is one of only two factories in the world that successfully produces curling stones: the other is in Canada and uses Welsh quarried granite. “China, Finland, Russia – everyone has tried it,” explains Hunter. “The advantage we have over every other place is Ailsa Craig.”

Hunter, who lives in Mauchline, has overseen operations for 17 years. He spent decades working in the knitwear business, but when the once thriving textile industry in Ayrshire fell into decline, the 64-year-old swapped wool for granite.

He gives me a tour pointing out the stages of the process including rough-shaping from what they call “a cheese” – the basic shape of a curling stone – to it being polished up to shine like a new penny. Hunter keeps an eagle-eye on proceedings and checks each stone before it leaves the factory.

“We don’t have two qualities of curling stone,” he asserts. “My job in the knitwear industry was quality control and it is the same here. Every stone we make is to Olympic standard: no matter whether it is going to Scotland, Russia, China – or wherever.”

Hunter traces a finger around the raised surface on the bottom of a curling stone. It feels rougher to the touch than the cool, smooth granite. “The running edge is the part which touches the ice,” he explains. “If that’s not right, well, you may as well be throwing a cup up the ice.”

To that end, tradition is key. Gazing around the factory floor some of the machinery wouldn’t look out of place in a museum. “Modern machines wouldn’t last five minutes in here – we would destroy them,” says Hunter, with a wry laugh.

“There is nothing modern in the curling industry. We have five machines that have been adapted to what we need. The oldest dates to 1948 and they go up to 1960.” He pats the nearest. “This one is from 1952.”

The Herald: Bill Hunter, factory manager at Kays Curling in Mauchline, Ayrshire. Picture: Kirsty AndersonBill Hunter, factory manager at Kays Curling in Mauchline, Ayrshire. Picture: Kirsty Anderson

Each curling stone weighs 40lb (18kg) and costs £460. Perfection is the aim. “In curling you have three elements: ice, human being and stone,” says Hunter. “During a game only two things change: the ice and the human being. The stone? It never changes.”

With up to 1,500 stones produced annually, Hunter has handled thousands over the years. He holds out callused palms, gesturing to where the edge of his hands appear moulded into a distinct curve. “They are shaped like that now – just like a curling stone,” he smiles.

A fresh “harvest” of granite takes place on Ailsa Craig every 10 years. It is transported back to the mainland on boats and stored at a yard in Girvan until needed. Kays has the sole lease to use this granite.

According to Mark Callan, resources are unlikely to dwindle. “We would need to turn the island into Atlantis to run out – that’s not going to happen,” he says.

While there is a sense of occasion around the harvest – the last one was 2013 – it is arguably a more low-key affair than in the past. “In the old days they used to blow it up with dynamite, but these days Mother Nature is our best ally,” says Callan.

“These are sheer rock faces – the island is 1,100ft high – and the weather combined with the gelignite used until the 1960s means there is a lot of fissures and cracks. We don’t need to do any blasting. We show up and it is all sitting there waiting for us.”

While the exact origins of curling are unknown and often disputed – two paintings by the 16th-century Flemish artist Pieter Bruegel, Hunters in the Snow and Winter Landscape with Skaters and a Bird Trap, are believed to depict a similar activity being played on frozen ponds – it is a pastime that has been woven into the fabric of Scottish life for generations.

The first recognised curling clubs were established in Scotland and during the 19th century the game was exported wherever Scots settled in cold climates, notably in Canada and the US.

Football – alongside rugby and golf – may often be hailed as our national game, yet it could be argued that curling has equal right to that title.

It was Scots who won curling gold at the inaugural Winter Olympics in 1924. Willie Jackson was the skip of a Great Britain side that also included his son Laurence and compatriots Robin Welsh and Tom Murray which triumphed in Chamonix.

Although awarded “demonstration medals” at the time, these were upgraded to official status in 2006 after The Herald filed a claim on behalf of the families of the team.

More recent times saw the all-Scottish line-up of Rhona Howie (nee Martin), Fiona MacDonald, Janice Rankin, Debbie Knox and Margaret Morton win gold at Salt Lake City in 2002. The rinks of David Murdoch and Eve Muirhead claimed silver and bronze respectively at Sochi 2014.

The Herald: Curling stones being made at Kays Curling in Mauchline, Ayrshire. Picture: Kirsty AndersonCurling stones being made at Kays Curling in Mauchline, Ayrshire. Picture: Kirsty Anderson

There is huge pride among the small, loyal workforce in Mauchline to see their stones used in all the international championships. “It is a great feeling when you see the finished article out there on the ice in front of millions of people,” says Callan.

Nor is it goodbye for ever once a stone leaves the factory. Callan, 52, travels to rinks worldwide to service them. He is newly returned from South Korea, set to host the 2018 Winter Olympics, and about to fly to Russia for the third time this year.

His other enduring passion over the past 30 years has been creating perfect playing conditions on the ice. As Callan speaks about temperature, humidity, dew point and heat load, it quickly becomes apparent that it is far more complex than simply freezing some water.

"Take a big championship with 2,000 people watching," he says. "If it is a humid, rainy day as soon as they come inside with their wet jackets on, the humidity is going to rocket and that affects the ice.

"We have had a refrigeration system blow up in the middle of a tournament. You then need to get hold of the chief umpire and say: 'Look, you've got 20 or 30 minutes of game time left and then it's going to become dangerous to keep people out there because the surface will get really slippy …'"

Callan's expertise is much in demand and he has been appointed head ice technician for the forthcoming European championships. "It is about providing the best possible playing conditions to allow the players to show their skill – you want it be a game of skill rather than luck."

A short drive away in Troon is the former home of the late David Buchanan Smith, one of Scotland’s best known sheriffs, who amassed an extensive private collection of curling memorabilia.

After Smith died last November, aged 79, his collection was bequeathed to the Scottish Curling Trust. Many of the pieces – including some 400 rare stones – have never been on public display.

It is the ambition of the trust, working alongside the Royal Caledonian Curling Club and Stirling Council, to build a museum to house it alongside other artefacts.

In the meantime, the collection has been moved to a secure location where trustees Graeme Adam and Bruce Crawford are pointing out some of the more unusual items.

Adam, 62, a retired GP from Dumfries bends down to inspect a label attached to one of the stones. “Johnny Hibberd and I got these from a public park in Dalry in 1977,” reads Adam aloud from the handwriting of the man many in the curling world reverently refer to as Sheriff Smith.

Around the room, the shelves groan with memorabilia. The curling stones range in size from tiny novelty items that could balance on a fingertip to a back-breaking brute weighing 117lb (53kg) and even an iron creation reputed to be made from melted-down cannonballs.

The Herald: Curling stones from the collection of the late David Smith. Picture: Kirsty AndersonCurling stones from the collection of the late David Smith. Picture: Kirsty Anderson

There are boxes filled with event programmes, medals and trophies, photographs and yellowing newspaper cuttings alongside a row of curling brooms which show the evolution from what looks like a clutch of straw and twigs up to the high-tech brushes used today. “I could happily spend days here,” says Adam wistfully.

“It is a unique collection that Sheriff Smith dedicated his life to putting together. I went to his house years ago and there was literally stones everywhere: under the beds, beneath the seats and in almost every room. There was another load in his garden that had been built into a wall.”

After studying law and working in Edinburgh, Paisley-born Smith was appointed sheriff for North Strathclyde at Kilmarnock from 1975 until his retirement in 2001. “They used to call him the dancing bear because he was a big man – in both personality and build,” says Adam. “His other nickname was the Ayatollah. He was quite a character.”

A curler for half a century, Adam enjoyed playing against Smith on several occasions. “Sheriff Smith always talked about the time he beat me 18-2,” he says. “It was in what was called the under-35s at that time. He never forgot that game.”

Adam took up curling in his second year at Hutchesons’ Grammar School on the south side of Glasgow and honed his skills at nearby Crossmyloof, the first indoor ice rink in Scotland.

“Back then you would give the ice man sixpence to bring the stones out and cool them down beforehand otherwise they were too hot and would sink into the ice. I would practise there every afternoon and then catch the bus home for tea.”

Curling is known as the “roaring game”, not for the shouts of “hurry hard” from the players as many people imagine, but in reference to the distinctive sound of the stones travelling across a frozen loch. “It is a wonderful noise when the stone goes over the ice outside,” says Adam. “It is a deep rumble, almost like thunder.”

His love of curling hasn’t waned over the years, although Adam – who has won Scottish schools, juniors, men’s, seniors and masters titles – laments the lack of outdoor games these days.

“We’ve not been able to play outside for the past few years because it has been too mild and the lochs haven’t frozen,” he says. “We did curl on Lochmaben six or seven years ago – albeit against the advice of the police.

“Curling outside is super. The whole atmosphere is different. Skill doesn’t matter as much outdoors. It is just a good laugh with a wee dram afterwards. It must have been wonderful in the old days when they drew cars up to the side of lochs and used the headlights to illuminate the ice.”

The Herald: Bruce Crawford, chief executive officer for the Royal Caledonian Curling Club, and Graeme Adam, trustee of the Scottish Curling Trust. Picture: Kirsty AndersonBruce Crawford, chief executive officer for the Royal Caledonian Curling Club, and Graeme Adam, trustee of the Scottish Curling Trust. Picture: Kirsty Anderson

It is estimated that 20,000 people in Scotland play. Bruce Crawford, chief executive officer for the Royal Caledonian Curling Club, hopes the buzz of Europe’s best players descending this month may entice more Scots to give it a go.

The eight-day tournament is the first of a series of major competitions: the 2018 World Junior Curling Championships in Aberdeen, the 2019 World Wheelchair Curling Championships in Stirling and the 2020 World Men’s Curling Championships in Glasgow will follow.

“Since curling was reintroduced to the Olympics in 1998, there has been that once-every-four-years spotlight and then people tend forget about it,” says Crawford. “Hopefully hosting these big events will give us the opportunity to raise where curling sits within the public consciousness.”

The Le Gruyere AOP European Curling Championships 2016 is at Braehead Arena in Renfrewshire from November 19-26. Visit ticketmaster.co.uk. For more, visit trycurling.com