Interview: Joseph Bonnar, Edinburgh jeweller

JOSEPH Bonnar hands me a beautiful faux crocodile skin box as green as envy. When I lift the lid, I am momentarily blinded. Inside, nestling on a bed of velvet, is a fireworks display of gems – a daz zling brooch exploding with diamonds, shimmering in a platinum setting. This radiant pin, French, dating from the mid-20th century, is one of the stars of the flamboyantly smart Edinburgh jeweller's collection this winter and he's confident that some lucky lady will discover the diamond cracker in her stocking on Christmas morning.

When he sourced this gorgeous piece, the largest diamond at its centre was missing. Had it still been there, says Bonnar, then its 18,800 price tag would double. Instead, he's placed at the heart of the brooch an exquisite natural, black-cultured pearl, which complements the 18.30 carats' worth of diamonds.

Sixty-one-year-old Bonnar, whose name is synonymous with style, knows all there is to know about dangling the carat anyway. This year he's celebrating his 40th anniversary in business alongside other luxury retailers in the capital, such as his fashion boutique neighbour, Jane Davidson, and florist Thomas Maxwell in nearby Castle Street.

"It's extraordinary that the three of us all started up in business in the same year, 1969. There must have been something in the zeitgeist. Perhaps Edinburgh was finally ready for fabulous fashions, flowers and jewels," muses Bonnar, who initially launched his business in Forrest Road in the city's first antiques market.

"I was staying opposite. I had no hobbies, so I thought it would be fun. I got the bored wives of two naval officers to run my stand. I put junk from my flat in it and, as it sold, I replaced it with jewellery." Today, he owns a glamorous store that sits in the midst of Thistle Street, one of Edinburgh's cult fashion destinations.

One of the city's most colourful characters, with a shock of snowy hair that makes him resemble an Enlightenment savant in a Savile Row suit, Bonnar is famed for the opulence of his stock and his wicked wit. He's also known for casting his pearls of wisdom – about everything from pearls themselves to sensational and unprintable gossip – before wine at the fabled parties he sometimes throws with great panache in his elegant New Town home. A Bonnar party is a party with jewelled knobs on, and that merely describes the guest list, which might range from various aristos and the Edinburgh establishment – the wife of a former Moderator of the Church of Scotland, say – to Britain's first transsexual, the alluring April Ashley. The former Liverpudlian merchant seaman has even modelled Bonnar's baubles, bangles and beads for a series of photographs that are displayed in a shop that's been visited by everyone from Hollywood stars – a frail Bette Davis, Lauren Bacall (Bonnar had no idea who she was but his mother recognised her gravelly voice) and, more recently, Tilda Swinton – as well as the denizens of Scotland's Rich List, although, despite his love of a scurrilous story he's infuriatingly discreet, refusing to name names.

That discretion is para-mount, he says. "People expect privacy because jewellery is always bought for an occasion, whether big or small. So there's profound emotion attached to jewels: they're full of sentiment and romance."

Dunfermline-born and educated at the town's Queen Anne High School, Bonnar cheerfully admits he was not remotely academic. But he was artistic, and by the age of 19, had his own design company in Edinburgh, with a staff of four, specialising in windows, interiors and exhibitions. "They call it visual merchandising nowadays," he says, languidly lighting up the first of a chain of cigarettes.

Over a cup of coffee in his sumptuous art-and-antiques-filled drawing room, we discuss how he made the transition into selling jewellery. "I've no idea why I went into the business, but I did like unusual things and I always used to buy my late mother little pieces from the dozens of junk shops we had in Edinburgh back then."

The first piece he bought was a Victorian brooch, a carved hand in jet, he recalls. "I wish I'd known it would become a career because I would have taken the double route I always advise my staff to follow, which is to work for a fine retailer and spend time with a big auction house, so that you get to handle a great many rare and exceptional things. Also, you then have contact with experts; I've had to do everything in reverse.

"I started by just selling things I found visually appealing, mainly because I didn't have the money to buy precious things. Looking back there were some extraordinary things. For instance, I bought a shoeboxful of jet, which had connections with Balmoral, when people said it wouldn't sell. It did! I pinned dozens of pieces on red watered silk – it was a real blast. Then Harper's Bazaar did an article about my tiny shop in St Stephen's Street, where I'd moved in 1972, before settling in Thistle Street a couple of years later."

So he had an eye? "So I'm told," he says archly. "Things were remarkably available in Edinburgh in the late 1960s. No-one in Scotland was treating antique jewellery as fashion." It was never just about antique jewels, he insists. It's always been about making people look amazing. Splendid jewels, be they diamonds or paste, can turn everyone into a star, he maintains. Jewels give pleasure – and then there's the treasure principle. "You can smell an heirloom: it has an aura about it, although once a piece has been exposed through auction the lustre dims."

Everybody who is anybody comes into his shop, from besotted young couples buying the engagement ring to international movers and shakers, as well as the crowned heads of Europe. "One morning a very tanned, very smart couple were wandering around the antique market. They clearly had a very practiced eye. I thought, 'Aha, London dealers!' She was in a Baccarat suede suit; the chap was in knickerbockers with a pearl-grey stetson. They said they were looking for jewellery. 'Are you in the trade?' I asked. To which she replied, 'What's that?' She said, 'No, it's gifts for my maids'. I wasn't that impressed. They settled on some mineral bead necklaces, all very pleasant. Only the next day did I discover it was only Princess Margaret and Colin Tennant, my dear. I felt so foolish."

Nonetheless, almost single-handedly, Bonnar has transformed the antique and costume jewellery business in Scotland into the height of fashion, rediscovering tiaras, le Style Ecosse, embracing Scottish and Highland jewellery from an era when the Victorians were stoned on stones and indigenous gold, and Art Nouveau and Art Deco, demonstrating how these can be worn in a chic, modern way.

He insists he'll never write his memoirs, but, if he did, he could call them Jewel Control, for his friendships are as legendary as his knowledge of vintage gems. One of his dearest friends was the late Countess of Galloway, whose astonishing story was related brilliantly in Louise Carpenter's An Unlikely Countess, which told how an Edinburgh commoner, Lily Budge, married the 13th Earl of Galloway in secret, only for him to be tragically disowned by his family.

Lily, who had an antique shop in Thistle Street, would often turn up at Bonnar's glitzy gatherings dripping in borrowed diamonds and he would regale her with naughty tales of his "florid nightlife".

Perhaps because of his famous discretion, Bonnar's clientele is as loyal as his many friends. "Now I am getting the children of women who first shopped with me in the 1980s! But their mothers still come in and their grandmothers. It doesn't matter how old or how young you are, you can always find the piece that will give you the look."

The biggest change in 40 years, he says, is the fact that women have become more and more independent, often buying expensive jewellery for themselves. He invariably suggests that they plump for pearls. "There's nothing quite like a girl in pearls." He explains that there's still a stigma attached to a woman buying her own precious jewels. "But pearls, definitely! You must wear them all the time. A retired Army officer once came in and opened his shirt to show me his pearls amid the grey hairs of his chest."

So, pearl's a winner? "She sure is!" exclaims Bonnar. Just don't say the b-word – bling – in his hearing. "Darling, I do not trade in bling," he shudders. "Not even in a recession. The answer is to fill your shop with twice as many flowers."

Thistle Street traders, including Joseph Bonnar, as well as the many other boutiques and restaurants, have late-night Christmas shopping events on 26 November and 20 December.