Diamonds: No longer a girl's best friend

As the stars lined up for the 70th Annual Golden Globes Awards in Beverly Hills the glittering jewels adorning the necks and earlobes of Hollywood's A-listers came courtesy of the most expensive brands on the planet. Actresses Catherine Zeta Jones, Sienna Miller and Isla Fisher and singer Adele were bedecked in exquisite pieces from Cartier and Van Cleef & Arpels.

The parent company of these brands will reveal just how booming expensive jewellery is in its results tomorrow. Swiss-based Richemont is expected to report a 11 per cent jump in third-quarter sales.

Luxury goods groups that have traditionally focused on other types of flashy products are also looking to get in on the action. Last week, Swatch, the watchmaker, snapped up the jewellery arm of Marilyn Monroe-favourite Harry Winston in a deal worth more than £600m.

John Guy, an analyst at Berenberg Bank, thinks the move is a "positive strategic step" which will help Swatch expand its "footprint in prestige jewellery as well as into the Americas".

Monroe may have sung that diamonds are a girl's best friend, but there are other, lesser known precious gems that are starting to become very good mates indeed. Morganite, from the colourful beryl family of gemstones that include emeralds, and labordorite, which is said to promote psychic abilities, are just two emerging rocks.

Jeweller Bec Astley Clarke says: "Women are now buying their own fine jewellery and not just relying on gifts from men. The old fashion advert of a diamond nestling in a cleavage is not what women want.

"We are certainly noticing a trend toward women wanting to learn about expensive gemstones. They love the colours and they want to be educated. Often these precious gems are worth a lot more than diamonds."

A savvy businesswoman is backing Astley Clarke's claims. Carmen Busquets, the Venezuelan luxury-goods investor who made almost a £100m profit from the sale of fashion website Net-a-Porter, has invested close to £1m in the business.

Astley Clarke is using this to help expand her brand online and also put the gemstones into shops. She now sells in Selfridges, Liberty and Harrods and could open a dedicated store in London in the next 18 months. Next is Asia and the US.

The people at Fabergé agree that women are driving the market. The brand, synonymous with Russian tsars and famous for its intricately designed ornamental eggs, has been bought by AIM-listed Gemfields, which is 63 per cent owned by former BHP Billiton boss Brian Gilbetson.

Fabergé's managing and creative director Katharina Flohr says: "We are continuing to see women buy jewellery for themselves – it's about empowerment, successful career women rewarding themselves.

"Across our network, jewellery under £80,000 is mainly bought by women. Women are becoming more adventurous, from traditional stones such as emeralds and rubies to more unusual stones like paraiba tourmalines, spessarite garnet and fire opals."

She adds: "We are seeing coloured gemstones making a comeback. Women are seeking jewellery that is more complex and ornate and isn't shy of colour – bright is beautiful."

Mining is out of vogue

Gems are "in" but diamond mining is out of fashion for traditional mining concerns.Last year, BHP Billiton sold its 80 per cent stake in the Canadian diamond mine, known as Ekati, to Harry Winston for $500m (£315m).

Now that Harry Winston has offloaded its jewellery business it could be ready to buy out its joint venture partner Rio Tinto from the unloved Canadian Diavik mine, raising its 40 per cent stake to 100 per cent.

BHP and Rio have sought to exit the diamond sector on the grounds that it is too small and risky a market for them to operate in. Anglo American is the only large-scale diamond miner left – it owns 85 per cent of the jewellers De Beers.

The supply of good quality diamonds is key to the brands. Laurence Graff's Graff Diamonds owns a stake in miner Gem Diamonds while US retailer Tiffany & Co is funding part of AIM-listed DiamondCorp's development of the Lace Mine in South Africa.