THE thing about sculpture, Tim Pomeroy tells me, is it comes with an extra dimension. "A painting takes you up to the edge but you never see what's around the corner, he says. "With sculpture you get to see what's around the corner."

Pomeroy is, yes, a sculptor. But he's a sculptor who paints. He's also a poet and a folk singer who plays the odd gig in the bistro in Brodick. In short, Pomeroy is an artist who, like his art, comes in full 3D effect.

He's charming, good company but there's a grain of determination and seriousness running through him. The words he uses to describe his approach to work are thrawn, stubborn, even Presbyterian. Possibly more granite than sandstone then.

Pomeroy works in wood too, but stone is his medium. Carrera marble, Kashmiri and Chinese granite, Cumbrian slate, Portland stone. He takes them and transforms them into art that draws on the natural world and on the influence of historic and religious relics.

"I'm very interested in permanence," he says. "I have no interest in making temporary statements. And I know that permanence itself is a relative statement. But I want to invest what I make with notions of permanence, with notions of the sacred … Yeah, it's serious. It's not easy, it's not frivolous, it's not superficial."

It's beautiful too. But before we get to that let's make our introductions. In person Pomeroy is a silver-haired, well-preserved 57-year-old. He meets me off the Ardrossan ferry with a hand-lettered sign with my name on it. The hand lettering, as you might expect of an artist, is impressive. I should have asked him for it.

We jump in his truck and head out of Brodick, to his home a few miles away where he lives with his Dutch wife Josephine who is also a painter, several ducks, a sculpture and a painting studio, a fetching view of Holy Isle when the weather's clear and various pieces ready to be boxed up and shipped to London for a new exhibition at the Fine Art Society in Mayfair.

Outside, there's a Chinese granite sphere which has been shaped and polished into a gleaming obsidian sphere inspired by Neolithic balls. it won't be making the journey. It weighs 800 kilos and the Fine Art Society is not sure its gallery could bear that.

The exhibition in January will be his second with the London gallery (he has also had one in its Edinburgh gallery). It will consist of mostly new work, created in the last nine months. In front of the house there is a fluted marble shape based on a butterfly egg, while in the studio there's a piece of marble that looks as if it has been crumpled up by giant hands. It is based on the desiccated skin of a passionfruit (one that Josephine had gilded for him for St Valentines' Day). It looks, I tell him, a little like a Ferraro Rocher. Maybe I've been watching too many Christmas adverts.

All of this is the result of hard work. Stone, he says, is not a giving material. The butterfly egg required 300 hours of polishing alone. "I'm very lucky that I'm physically able because I'm nearly 60 and it's an arduous day's work."

But he can't imagine doing anything else. "There was a programme on the television not that long ago called What Do Artists Do All Day? And artists just basically 'art' all day. Well, good ones do. I have a programme of work – Presbyterian – that's going to happen whether or not any galleries are going to show it because, basically, I'm alive and I've got a lot of ideas."

You could say that Pomeroy is a self-made artist. He was not encouraged by his parents or at school to pursue the subject. He grew up in a middle-class home in Hamilton with two sisters. His father was mathematically minded. Art was not part of the picture.

Pomeroy went to Glasgow University to study Latin, Greek, Anglo-Saxon and Scottish history. "Failed miserably," he says of the experience. Art school was not something he thought about though. After dropping out of university he tried his hand as a folk singer and then worked in a children's' home in Pollockshields.

He was on course to become a social worker when the idea of art school first surfaced. He did his Art higher at night school and then went to Gray's School of Art in Aberdeen for five years and, he says, "became a comet."

Art school was an eye-opening experience. "Suddenly one realised that the emotions were the very currency of what you were doing as opposed to the things you squashed back and didn't admit to or examine or talk about. Suddenly the emotions were the vehicle through which everything became possible."

That said, he emerged from art school at 26 aiming to be a lecturer, because that was "the best I thought society could offer." He enjoyed it. And it was how he met Josephine who was one of his students. But six months down the line he decided to try to be an artist.

His stubbornness emerged here too. Rather than find a gallery to represent him he went his own way. As a result he led a hand-to-mouth existence for several years before a show in 1991, inspired by the Gulf War. "I thought it was a great exhibition and it went nowhere. I sold enough to keep going for another year but there was never any critical recognition."

At which point Pomeroy recognised that he needed to change his approach. "I thought I've got to go and find a gallery like every other artist in the bloody universe does."

So he did. It helped too that the start of the 1990s saw the beginning of the National Lottery money filtering into funding public art. He began to get commissions for those and he began to sell.

We live in a world of public art now of course. Some of it good, some of it not quite so, he admits. "Some of them are terrible. There have been times when I thought we'll start a cultural militia group and we'll go out at midnight and blow up all this bad art."

Why is it bad? "Nobody has the balls to say 'this is crap, this is rubbish.' And I know this sounds very Draconian. There's nobody prepared to say on the panels that judge these things this is simply not good enough."

Which ones would he blow up then? "There's one of mine that's pretty terrible actually."

Last year, Pomeroy tells me, he worked on Bert Jansch's gravestone in Highgate Cemetery. Another example of how we use stone to represent permanence for us. Stonework as a marker of human history, of human belief, has long been an abiding interest, ever since he first went to Kelvingrove as a kid looking at Ancient Egyptian clay fragments.

The art he has loved from prehistory to the Renaissance and beyond has always been concerned with God and Gods. The question is, then, is he religious himself. When he uses the word Presbyterian to talk about his work ethic is he also talking about himself?

The answer is complicated. Pomeroy didn't grow up in a religious household, but during that year of studying Latin and Greek he had something of a crisis. He spent most of his time at uni divided between the snooker hall and the chapel. He was, he says, "completely rudderless." That's when religion found him. "A religious fervour came into me which stayed for years and years and years."

No longer. "I can no longer intellectually call myself a Christian," he says. "I might have done at one time. I don't know what to call myself to be honest. But there is something about me that believes in something. It believes in me. It believes in life."

God is no longer part of the equation for him, and yet, he says, "I have this thing I can't escape from. It's an insistence."

What does that leave? A belief in what he calls an "otherness". What that otherness is he can't put into words. But it's there when he works with the stone.

"I think I'm still on the same mission as the guys who made the Cuneiform tablets, the guys who made the Sphinxes, the guys who made the standing stones. I think I'm one of them."

He smiles. Outside the sun has come out. It flashes on polished stone.

Ritual Geometries: New Sculptures by Tim Pomeroy opens at the Fine Art Society in London on January 9 and runs until January 30. For more details visit thefineartsociety.com or the artist’s website timpomeroy.com