By Ase Anderson in London

Pearls have shaken off their fuddy-duddy image and are on course to rival diamonds as the fashion set's choice of gems, with natural pearl necklaces and earrings smashing records at auctions.

No longer seen as the preserve of twin-set-wearing ladies who lunch, these treasures of the sea are now gracing the necks and earlobes of style icons such as Sarah Jessica Parker, Kate Middleton and Angelina Jolie.

The trend is reflected at the big auction houses, where natural pearls are increasingly beating their pre-sale estimates and going under the hammer for record-breaking sums. The Graff Vivid Yellow diamond may have dominated the headlines after last month's Magnificent Jewels and Noble Jewels at Sotheby's Geneva, but natural pearls also performed extremely well, with many lots far outstripping their estimates.

An important natural pearl necklace, consisting of a strand of graduated natural pearls measuring between 7.75 and 12.15mm sold for almost $3 million - more than eight times its estimate. And at the same auction, the hammer went down at $1.02 million for a natural pearl necklace with rubies and diamonds, four times the estimated price, while a natural pearl necklace beat its pre-sale estimate more than 12-fold, fetching close to $831,000.

May 2014 saw the sale of the largest natural saltwater pearl ever to appear at a public auction. Weighing an impressive 33.15 carats, the pearl was sold for £811,000 at British auction house Woolley & Wallis, far higher than the £80,000-120,000 estimate. Believed to be one of the largest in the world, the pearl was bought by David Morris jewellers, who intend to incorporate it into a necklace.

In April this year a pair of extremely rare natural pearl earrings that once belonged to Empress Eugenie of France, the wife of Napoleon Bonaparte, set a new world record for a pair of natural pearls when they were auctioned for US$3.3 million by Doyle New York. The warm-grey drop-shaped pearls measure 23mm high by 13mm wide and are mounted in antique silver and diamond caps which were set onto a platinum and diamond pendant, dating from the 1920s. The earrings were accompanied by a note saying they had once belonged to Empress Eugenie, as well as a report from the Swiss Gemmological Institute SSEF, attesting to their extraordinary characteristics.

The final sale price was $900,000 higher than the previous record for a pair of natural pearls, which was set when Sotheby's Geneva sold a pair of pendants that previously belonged to Italian actress Gina Lollobrigida for $2.4 million in May 2013. That pair in turn broke the $1.99 million set by Christie's New York in 2011 at the auction of Elizabeth Taylor's jewellery.

Natural pearls also led to intense bidding at Christie's Magnificent Jewels sale in Geneva last year when a single-strand natural pearl necklace set a new world record for a piece of its kind, selling for $8.5 million, way above its $2-3 million estimate. And in May this year Christie's Geneva sold a natural pearl and diamond necklace from the Estate of Baroness Gunhild Thyssen-Bornemisza de Kaszon for just over US$3 million.

British auction house Bonhams attributes the fierce bidding and escalating prices to the increasing rarity of natural pearls. The supply of new natural pearls has been hit hard by a combination of overfishing and pollution. As a result, the number of quality natural pearls going under the hammer - in terms of size, shape, lustre and lack of blemishes - has dramatically decreased in recent years.

Jean Ghika, head of jewellery in the UK and Europe at Bonhams, says: "Long term, [natural pearls] will become more of a rarity and therefore even more highly prized. As a result, pearls that have some age, or were part of a historic collection, can be highly appealing to potential buyers and investors." This winning combination of history and provenance came together perfectly with the sale of the 16th-century La Peregrina, a pear-shaped natural pearl whose history spans 500 years.

It caused a bidding war at Christie's New York in 2011, when Elizabeth Taylor's collection of jewels went under the hammer. Estimated to sell for $3 million, it vastly exceeded its estimate, achieving a huge $11.8 million, with the fact that Taylor had commissioned Cartier - one of the world's most famous jewellers - to redesign the necklace, setting La Peregrina alongside pearls, diamonds and rubies, only serving to increase its desirability.

Ghika adds that the "Kate Middleton factor" has also played its part in making the gems more appealing to a younger generation. The stylish Duchess has been spotted pairing pearl jewellery with fashionable outfits on several occasions.

"Pearls were once seen as a bit dated, perhaps the preserve of an older generation, but we've seen a complete change in how they are viewed," she says. "A younger fashion set is now completely at home wearing classic pearl earrings and you're as likely to see them in nightclubs and at premieres as you are at Ascot or the Epsom Derby."

Read more on the history of pearls