“She is more precious than rubies,” says the Bible of a virtuous wife. Precious stones abound in the Holy Book – not just rubies, but emeralds, sapphires, topaz, onyx, jasper, chalcedony and whatever else the authors felt would emphasise the immeasurable value of chaste spouses, wisdom and other priceless commodities, or enhance the status of kings and angels. Diamonds, however, are thin on the ground, their colourless sparkle evidently not much prized in the Middle East of a few millennia ago.
In the 20th century, diamonds were top of the gem pile – at least in part because of a stunningly good marketing job by De Beers, which held a monopoly of the business. Women could not get married without a diamond on their finger. But the collapse of De Beers’s monopoly undermined the scarcity that the marketers had worked hard to create, and the price of run-of-the-mill diamonds has stagnated since the early 1980s.
Coloured stones, by contrast, are genuinely scarce. That helps explain why, in recent years, the value both of coloured diamonds and of other types of precious stones has been rocketing. Earlier this year a huge pink diamond became the most valuable gem ever sold when a Chinese company bought it at auction at Sotheby’s for $71m. A month later a pair of matched diamond earrings, one pink and one blue, became the world’s most expensive when they fetched $57m (buyer unknown).
At the heart of this boom is a huge increase in the number of wealthy people willing to pay vast sums for unique gems, coupled with a tiny supply of truly exceptional new stones. “There was only one arrow, and that was up,” says Alisa Moussaieff, a jeweller and diamond dealer to the world’s very wealthy, of rare coloured diamonds. “There is no question that there are fewer high-quality stones and more buyers on the market.”
Demand for vibrant colours has also spilled over into diamonds’ most aristocratic of cousins: rubies, sapphires and emeralds. Take rubies. Their price more than doubled over the decade to 2015. Driving up prices were buyers in China, for whom the stones’ colour symbolises prosperity and royalty, says Ian Harebottle, the chief executive of Gemfields, the world’s biggest miner of rubies and emeralds. Other new entrants to the world’s plutocracy are also bringing home-grown tastes to the gem market. India’s Bangalore-based technology titans are particularly keen on yellow sapphires, says Guy Clutterbuck, an independent gemstone hunter.
Another reason for surging prices is that Gemfields has started to consolidate a fragmented and largely artisanal mining industry – trying to do for coloured stones what De Beers did for diamonds. After buying the world’s largest emerald mine and biggest ruby deposit, it now accounts for 30-40% of the world’s supply of these two gems. This has allowed it to ensure a steady supply of stones to jewellers and also given it an incentive to invest in marketing them.
The company now spends about 15% of its revenue marketing the stones. The impact is evident in the price of top-notch emeralds coming out of its mines, which has risen from about $4 per carat in 2009 to $70 last year. “We are trying to rebuild one of the world’s greatest industries,” says Harebottle. Among other investments his company bought Fabergé, a jeweller, to promote designs incorporating coloured gemstones.
Such efforts have been paying off, with almost all of the main houses expanding their lines. One jewellery firm with a long history of using coloured gemstones is Tiffany & Co. It helped develop the market for kunzite, a gem discovered in 1902 and named after its most famous gemologist, as well, more recently, as tanzanite, a gem discovered half a century ago in east Africa. Tiffany has seen “an intensely growing appetite for coloured gemstones,” says Melvyn Kirtley, the company’s chief gemologist.
New designs and techniques of working coloured jewels are also whetting customers’ appetites. Pre-eminent among the innovators is Albert Boghossian, a Lebanese-born Swiss jeweller whose nephew marks the sixth generation to enter the family business. Speaking in subdued tones and followed by an assistant who anxiously snatches and locks away jewels he has absent-mindedly left on this counter or that, he traces the evolution of the techniques his firm is pioneering. From one glass case he takes a flower carved from turquoise that is inlaid with diamonds, from another a sapphire carved into a bed of light blue chalcedony. Or take the work of Marco Bicego, an Italian jeweller who has been experimenting with unusual combinations that include green, grey and brown rough diamonds.
This flowering of creativity has boosted demand for little-known stones such as alexandrite, some of whose values have soared. Tourmalines, for instance, have tripled in price over a decade, not least because of their varied colours. “My favourite gemstones are blue sapphires...and all kinds of tourmalines,” says Bicego. “Tourmalines can have such an outstanding variety of colours from pink and green to blue and yellow. They are a real natural rainbow!”
Yet as tastes have broadened away from diamonds, so too have the risks consumers face. The size of the coloured gemstone market is less than a tenth as large as that of diamonds. And with its fragmented supply and huge variety of stones of different properties, it is far more difficult for consumers to understand. Some stones, such as tanzanite, must be treated to take on their colour and thus are, to a certain extent, human creations. But many other gemstones may be surreptitiously improved. Two rubies, for instance, may look identical to the untrained eye. But whereas the stone with a natural red hue may sell for as much as $30,000, a near identical one that has been heated may be worth just a few hundred dollars, says Stuart Robertson, the research director of GemGuide, which publishes the gem industry’s main price index.
And as much as these stones and colours may be opening up whole new avenues of exploration for fashionable designers, sometimes the oldest wisdom still holds true. In 1912, the style editors of the New York Times offered their readers a large spread on the etiquette of jewels. Among such dubious claims as the notion that a dark-skinned brunette who wears rubies ends up “eclipsing her best tones and producing only an unpleasing gypsy likeness” is one pearl that has retained its value: “The woman who takes care not to wear them for mere garish display can add much to her appearance.”