A prasiolite may not be for ever, but it is a girl's new best friend. For gems with names more likely to be found in a geology textbook than a high-class jeweller's are outshining diamonds, rubies and sapphires.
Sodalite and tanzanite don't sound romantic, but these semi-precious stones are now so popular that they make up nearly half of all pieces of jewellery sold by Britain's top designers.
Fashionable jewellers such as Stephen Webster, Theo Fennell, Pippa Small and Dinny Hall are turning their backs on diamonds and using lesser-known stones such as morganite, citrine and tourmaline.
But, while these are proving popular, buyers have been warned that the value of a semi-precious stone will diminish, as they are more likely to chip.
This is not stopping celebrities from queuing up to be seen with the latest designs. Model Liz Hurley, actress Uma Thurman and pop star Rachel Stevens are fans of Dinny Hall, while at last week's Grammy awards ceremony, pop star Christina Aguilera, rapper Jay-Z and country and western stars the Dixie Chicks wore jewellery by Stephen Webster. "These stones allow us to do something different," Mr Webster said. Even the term "semi-precious", he added, is out-dated. "I recently sold a tanzanite ring for $50,000 - you can't call that semi-precious."
It is a view echoed by luxury jeweller Theo Fennell. "Some of these stones can be far rarer and more beautiful than precious stones," he said.
The rising price of gold and diamonds has accelerated the semi-precious boom. Gold is more than $575 an ounce - an 18 per cent rise on last year. Prices of rough diamonds have risen by as much as 40 per cent in the past two years.
"Diamonds are extortionate," said Ms Hall. "People coming in for a pink diamond see the prices and choose a pink tourmaline or zircon instead." But it is for their vibrant and varied colours, rather than their intrinsic value, that designers such as Solange Azagury-Partridge - dubbed "Queen of bling" by Elle magazine - have turned to semi-precious stones. "You can't get a precious stone that is purple," she said. "Companies like Cartier have suddenly realised there is a big market in semi-precious stones."
Designer Pippa Small is of the same mind and said: "I don't feel there should be any reason why a crystal cannot be seen to be as beautiful as a diamond."
Asprey, the London jewellers, find semi-precious stones are now "incredibly popular". Lord Bruce Dundas, Asprey's managing director, said: "We have particularly noticed an increase in men purchasing them as gifts."
Then there's the sheer variety. Vicki Beamon, creative director of Erickson Beamon, said: "We have recently been designing with agate, jasper, coral, carnelian, rose and smoky quartz, tourmaline, carved jade, amethyst and rock crystal. Customers really are looking for a unique style."
The vogue for the stones could, in part, be due to ethically aware consumers veering away from "conflict diamonds". In the run-up to Valentine's Day, Amnesty International and Global Witness have published a guide to buying ethical diamonds. The charities saywarlords in countries such as Sierra Leone and Angola have used billions of dollars from the sale of diamonds to fund wars.
STEPHEN WEBSTER: 'There is no shortage of colour in a jeweller's window now.' Clients: Madonna, Cameron Diaz.
THEO FENNELL: 'The rare coloured stones are making a huge impact.' Clients: Elton John, Naomi Campbell.
PIPPA SMALL: 'They create fantasy and dreams.' Clients: Julia Roberts, Mick Jagger.
DINNY HALL: 'Diamonds are extortionate.' Clients: Liz Hurley, Uma Thurman.
VICKI BEAMON: 'Semi-precious stones have always been essential to our philosophy.' Clients: Kate Moss, Donna Karan.
Out with the old...
DIAMOND: Once queen of the stones, the diamond's image has been tarnished by being mined in war zones.
RUBY: Top rubies might be worth more than diamonds, but the red hue no longer lures the fashionistas.
SAPPHIRE: Princess Diana's engagement ring contained one. Designers now use cheaper alternatives.
EMERALD: According to Indian scriptures, they had healing qualities, but high prices can put people off.
In with the new...
MORGANITE: Sales of pink morganite rose after Ben Affleck gave an engagement ring to Jennifer Lopez.
TANZANITE: Made popular by Tiffany's, tanzanite is becoming more expensive as its popularity has soared.
PRASIOLITE: Greenish stone, produced by heating amethyst. Alternative to emeralds.
TOURMALINE: Called the "rainbow gemstone" due to its spectrum of colours.Reuse content