Wallis Simpson's jewellery: God save the bling

One of Wallis Simpson's most famous sayings was that "You can never be too rich or too thin," and she could well have extended the aphorism to say ... "or have too much bling." The stylish American for whom King Edward VIII gave up his throne had another epic love affair: with jewellery. Yet her baubles were more than just expensive adornments. Through them, history, fashion and romance are perfectly combined and preserved forever.

In the opinion of David Bennett, Chairman of Sotheby's Jewellery in Europe and the Middle East, Simpson's jewels are "the most important jewellery collection put together in the 20th century". When her collection was first sold by Sotheby's in 1987, the year after the Duchess of Windsor died (the sale was announced on 12 December 1986, exactly 50 years after the abdication), the auction held in Geneva caused a huge wave of interest. It eventually raised $50m (£31m) and set a new world record for a single-owner jewellery collection.

Today, 20 pieces bought from the original collection will be sold at Sotheby's, and are estimated to reach in the region of £3m. If the $43m difference between the estimate and the final figures for the 1987 sale are anything to go by, today's auction will raise considerably more than the estimate. While buying baubles at this level is the preserve of the super rich, it continues to fascinate a much wider group of people. Jewellery remains the most potent symbol of extreme emotions; of passion, faith, hope, power and greed. As Richard Edgecumbe, jewellery curator at the V&A told me when the museum opened a new jewellery gallery two-and-a-half years ago: "Jewels are a potent link with the past, a celebration of art and craftsmanship, and an embodiment of deep human emotions."

You only have to look at the interest around Prince William giving Kate Middleton his mother's engagement ring to see how charged with symbolism jewellery is. While clothes, shoes and bags receive far more attention in fashion terms because they are affordable and renewed more frequently, speculation about the royal meringue is so far secondary to the royal rock. Prince William said he proposed with Princess Diana's ring, "to make sure my mother did not miss out on today and the excitement that we are going to spend the rest of our lives together". To some the gesture will seem moving and optimistic, others will be unable to shake off the sense that the ring is associated with some rather bad karma, given the failure of his parents' marriage. The unhappy saga doesn't seem to have deterred consumers from wanting their own take on Princess Diana's sapphire and diamond ring, however, as the high-street jeweller H Samuel reports a 150 per cent increase in searches for sapphires on its website, along with a 400 per cent increase in searches specifically for sapphire rings. Engagement rings are charged with not just luck but etiquette – when Nicolas Sarkozy proposed to Carla Bruni with the same model of Dior ring he had given to his previous wife towards the end of the marriage, it was seen as a considerable faux pas.

Many believe jewels go far beyond mere protocol and that they can be good luck talismans, or cursed stones. As the private jeweller and Cartier expert Harry Fane, who owns the Obsidian gallery in London, puts it, "they have to be more than just rocks". The Hope diamond is the most legendary example of a stone deemed deeply unlucky, and unless you are entirely immune to superstition, the chain of ill fortune which has followed it seems convincingly dramatic. Believed to hail from the Kollur mine near Golconda in India, legend has it that the deep blue, 112 carat, golf ball-sized stone was taken from the brow of a temple idol by the French merchant traveller Jean-Baptiste Tavernier in the 1660s. From then until 1958 – when it was donated to the Smithsonian museum in Washington by jeweller Harry Winston, who sent it in a plain brown package by registered mail – it was associated with the premature death, madness, suicide and murder of many who possessed it, or their loved ones.

The Hope diamond is an extreme example of a stone, but a mix of attitudes towards buying pre-owned jewellery prevails among high-end collectors. According to Harry Fane, there are three main approaches to provenance. He says there are certain people who simply don't want to buy jewellery that has belonged to someone else; those who aren't concerned either way and will just invest in a piece because they like it, and those for whom the story behind a jewel, and in particular telling that story, will be more important than the piece itself.

According to Fane, in the Sotheby's sale "there is a synergy of all these elements. The collection has an extraordinary provenance, it is historic and romantic, and features major, exceptional pieces of jewellery by Cartier who were the 'King of Jewellers, Jewellers to Kings'. You can't get better examples of this kind of jewellery."

While Tuesday's sale of "Exceptional Jewels and Precious Objects formerly in the collection of The Duchess of Windsor", also contains items such as cufflinks, buttons and medals belonging to Edward in his early life, the jewels commissioned and exchanged by the king and his mistress-turned-wife are likely to generate the most interest. The gem-set and diamond cross bracelet by Cartier, is probably the most intimate piece, with each cross bearing an inscription marking a critical point in the couple's lives. One, reading "God save the King For Wallis", refers to an assassination attempt on Edward, another records Simpson's appendectomy. Another, with the words "The Kings [sic] Cross" marks the time in 1936 that, after a heated argument, Simpson hailed a taxi and said "King's Cross" to the driver. "I'm sorry lady," he replied. Perhaps the most remarkable item from a historical point of view is a gold and gem-set cigarette case given to Edward (or David as she called him) by Wallis for Christmas in 1935. On the lid is a map of Europe which shows holiday voyages made by Edward and his guests – including Wallis Simpson – in 1934, 1935 and 1936. The final holiday, taken in the summer of 1936, would have been marked on the case after Wallis had presented her lover with the gift. It is particularly poignant because in 1936 he made the historic decision to abdicate; it was during the cruise around the Mediterranean that the couple's relationship started to come out into the open after being reported in the international press.

Wallis Simpson was a style icon, thanks to her unswervingly simple and immaculate take on fashion. She was rigidly disciplined about what she wore and about her figure; to maintain the lean frame necessary for the sleek silhouette she favoured, it is said she would subsist on very little food if she felt she had gained weight. She was a mistress of self-invention and image, and it's hardly surprising that Madonna is making a film about her (WE, after Wallis and Edward, slated for release next year). Simpson's severe clothes provided the perfect foil for extravagant jewellery, and in 1936 as the love affair was about to reach boiling point, the society chronicler Henry "Chips" Channon wrote that "Mrs Simpson was literally smothered in rubies."

There's certainly nothing subtle about her taste in rocks, which seems to have become increasingly opulent throughout her life. One of the standout pieces of the sale – and one that became a familiar motif from the 1987 auction – is a ruby, sapphire, emerald, citrine and diamond flamingo clip, mounted by Cartier in Paris in 1940. In order to make the jewel, the Duchess had several of her pieces unmounted so the stones could be reused; she did this frequently, and even had jewels reset that previously belonged to Queen Alexandra. Encouraged by the Duke, the avant-garde statement was designed by Cartier's high jewellery director Jeanne Toussaint (the designer behind Cartier's Great Cat jewels, who was known by Louis Cartier as panthère) and designer Peter Lemarchand.

Another notable animal-inspired piece is the onyx and diamond panther bracelet, designed in 1952, by Toussaint and Lemarchand. When I visited Sotheby's to preview the collection, Alexandra Rhodes, of Sotheby's International Jewellery Department, took it out of the glass and placed it on my wrist, explaining that Lemarchand would sketch the big cats at the zoo in Vincennes in France, in order to make his designs as lifelike as possible. Its impressive miniature engineering – the articulated body enables the cat to lie sleekly over the wrist, its paw stretching outwards – conveys a powerful sensuality. Run your fingers across the pavé diamonds along its back and you can feel the animal's musculature. If the bracelet had been given to Simpson before the abdication it might have reflected her image as a sexual predator, a kind of "Mata Hari" as Hugo Vickers, author of Behind Closed Doors – The Tragic Untold Story of the Duchess of Windsor, to be published in April 2011, puts it, fuelled by society rumours that during a year spent in China in the 1920s Simpson had become skilled in the erotic arts. By 1952, however, the message is more like here is the cat that got the cream.

At least that's what it looked like on the surface. Perhaps, however, these later jewels tell the story not only of passion, but of excess and an obsession with style borne of lack of purpose. In her 1988 book The Windsor Style, Suzy Menkes reveals the underlying shallowness of the couple's life in exile in their lavishly decorated home in Paris. She repeats a line spoken by Edward VIII to a friend, in which he says: "You know what my day was today? I got up late and then I went with the Duchess and watched her buy a hat." It captures the rather empty pursuit of style that characterised their days. The Duchess declared that she "would rather shop than eat", and spent much of her time being fitted for couture dresses. In Menkes' book, the Duchess of Marlborough, one of the couple's social circle, is quoted as saying, "I went to look at the flowers at [the Duchess's funeral]. It was tragic. They were all from dressmakers, jewellers, Dior, Van Cleef, Alexandre. Those people were her life."

Of course this was over a decade after the Duke of Windsor had died, and the Duchess was left a widow, and few lives can live up to the unfading, eternal lustre of diamonds, sapphires and rubies. Despite the more nuanced reality behind the image, and the fact that the Duke was already disillusioned with the duties associated with being king when the romance blossomed, what these jewels will be associated most with is a love affair powerful enough to make a king give up an empire. That's what will bring down the hammer at Sotheby's tonight.