Queen of the stone age: Solange Azagury-Partridge has never been too precious to go her own way

Walk the glittering line of fine jewellery shops on Mayfair's Bond Street and you'll find that one in particular stands out – for its opulence, without doubt, but also for its character and its use of caricature, for its almost whimsically 'other' take on modern luxury.

Solange Azagury-Partridge's flagship boutique, with its red-velvet cases and carefully considered interiors (each piece of furniture and every fitting has been chosen by the designer herself), is a world removed from the jewellery label's origins in Azagury-Partridge's west London basement.

Hers is a fashionable fairytale: after designing her own engagement ring in 1987, her unusual and avant-garde pieces caught the attention first of her close friends and then a wider coterie, who placed orders, spread the word and eventually convinced her to set up business three years later.

She opened a first shop in Westbourne Grove in 1995, and added the Bond Street store in 2010. In 2001, she was personally approached by the designer Tom Ford to take over as creative director at the Parisian fine jewellery house Boucheron, which she left in 2004 to focus on her own line. Twenty-two years after its rather low-key inception, Solange Azagury-Partridge is a global name.

When I go to meet the designer in her offices a little further down Bond Street, my first encounter is with one of her employees, who is crying – not, as the fashion apocrypha normally goes, because her boss is such a tyrant, but because she is so sad to be leaving the firm. "S.A-P" will be ready in just a moment, she tells me between sniffs, and so I settle myself in an office more boutique than workplace, scattered with intriguing objets and eclectic furniture mismatched in all the right ways.

"Everyone has 'impostor syndrome', don't they?" Azagury-Partridge smiles, when we eventually sit down with tea and refined society's favourite nibble, a plate of pastel-coloured macaroons.

I have asked her whether she ever feels incredulous that her efforts have paid off so remarkably, a question at which many internationally renowned designers might bristle. But Solange Azagury-Partridge is not one of those designers: her perseverance and drive sit very naturally alongside her warm and natural ease. She is diffident without being shy, sure-footed but not abrasive.

"Yeah, I can't believe it," she continues. "But what I do is I keep my immediate surroundings very cosy, as if I were still only working with three other people. So there's 10 people upstairs, and there's another 10 people over there but I keep it very manageable, so that it doesn't send my head into overload."

But from their birth in that basement, her pieces have found their way into some of the most exclusive households in the world, and become cultural signifiers. She has "blown the dust off fine jewellery", one of her team tells me – which might not sound much, but consider how most prestigious sectors react to the arrival of a young woman with a strong sense of self and of style.

''Boucheron gave me the confidence to trust myself," she says. "[Tom Ford] asked me to do it and I said 'Of course I can,' thinking 'How on earth am I going to do this?' But you think, if they think I can do it, I must be able to."

She shrugs, matter-of-fact about the turnaround in fortunes that her tenureship brought to the company. "What you can't forget is they're big, rumbling, heavy businesses and it's hard to be fresh when there's a whole machinery behind you. I wanted to be quite extravagant, so that was my starting point – and to extract the sensuality of the brand."

Sensuality is key to Azagury-Partridge's work – along with a sense of humour and irreverence. Her best-known pieces are the enamel lip rings, which conjure the Pop Art references that resound throughout her work. Sculptural fluidity comes from tassels and fringing, modernist refrains by way of sliced diamonds, rough-cut gems and other stones handled with ingenuity, treated in ways often seen as sacrilegious by others in the trade.

"Always. Certainly," she sighs. "I always say, if you can send a man to the moon, you can make a piece of jewellery. I'm not gem-focused, which a lot of jewellers are. I like to design what I want to design and then squeeze the stones into it. So it becomes a nightmare of not only making the jewel, but cutting stones, sourcing colours, whatever."

She has worked thus since she created her first piece – her engagement ring, the rock that has become the foundation of her business and of her personal stability: her marriage and two children are what have kept her grounded, she has said. The ring itself was a rough diamond, which Azagury-Partridge insisted on having set in its natural state, without tidying up the edges. It was unheard of. And everyone who saw it loved it.

"I couldn't afford gold so I used silver," she recalls. "And then once I'd explored all the options with rough stones, I went on to cabuchons [the next step up in polished stones]. Every sale enabled me to make another piece of jewellery. I didn't really manage to live off my work for a long time. I just put it all back into the business – for one sale, I was able to make two more. I was able to grow my stock and my collection piece by piece."

But her arrival is now complete: in 2008, Azagury-Partridge partnered with the Labelux group, which also counts Bally, Belstaff and Jimmy Choo among its portfolio of high-end fashion brands, and took her label overseas. She now has shops in New York and Hong Kong. Her painted gold necklace hung around the neck of celluloid's foremost clothes horse, Sarah Jessica Parker, in the second Sex and the City film. This summer, her work shines as the Evil Queen's heart-plucking ring in the forthcoming film Snow White & the Huntsman. And her jewellery resides too at the V&A and in Paris's prestigious Musée des Arts Décoratifs.

"I like to think they are heirloom pieces," she says. "The intrinsic value of precious jewellery is that it's something you don't just throw away – either you re-model it, which I hope nobody will ever do with something of mine – or you hand it on."

Each Azagury-Partridge collection sees her involve herself with new (often arcane and under-used) techniques, and every piece's idiosyncrasies stand as proof of her constant struggle to push the boundaries of jewellery design. "I've learned about the history of jewellery as I've been designing. So the more I design, the more interested I am in lesser-known techniques or cultures. Everything interests me, it's a never-ending deep well of a subject."

Born in London ("conceived in Casablanca"), Azagury-Partridge studied languages at university, with the aim of becoming a translator, before going to work at the costume-jewellery shop Butler & Wilson after she had graduated. "I always had an eye," she says. "I always had a strong sense of aesthetics. I could have done anything visual. Had I ended up working in a dress shop, I would have started designing clothes and shoes. But I ended up working in a jewellery shop and that's where my focus took me."

"I never thought of Solange going into jewellery," says Simon Wilson, one of the store's owners. "I thought she'd end up in Hollywood! She was drop-dead gorgeous but such a straightforward and sweet girl. I still love her. She's still the unaffected person she was when she worked for me."

In fact, there is much that is grounded and straightforward about the way she does business. Twice while we are chatting, Azagury-Partridge takes calls from customers who want her personal opinion either on purchases they are about to make, or prospective bespoke commissions. She hosts intimate dinners on various continents to maintain links with her customers, and visits each of her worldwide stores at least once a year.

"Everything says something, everything has a hidden message," she explains. "But I've discovered you can't dissuade people, and sometimes people make the wrong choices. Someone bought an engagement ring the other day, and I think he made the wrong choice. I just thought 'If you give her that, she might say no but if you give her this, she'll definitely marry you'.

"But if that's what you want to do... I just think as long as it's beautifully made and it's done with integrity, and with heart, that's what matters."