Since DeBeers’ 1940s marketing coup with the now-renowned campaign slogan “a diamond is forever”, this stone has appeared to be just that – an enduring symbol of rarity and beauty touted across the global jewellery retail industry.
However, over the last 10 years, the market has seen a notable growth in the demand for precious coloured gemstones, particularly those from certain locations in the world that have not been subjected to any treatment used to improve their colour and clarity. On some occasions, prices for these significant gems have greatly exceeded those achieved for diamonds. As of 2014, the world record price at auction for the price-per-carat of a ruby fell just shy of $1million. Even the Elizabeth Taylor Diamond achieved only just over the $250,000 mark per carat in 2011. Here at Bonhams in London, we waved goodbye to 2014 with the December sale of a pair of art deco ruby and diamond clip brooches by Cartier for $785,000 – vastly exceeding the pre-sale lower estimate of $130,000.
When discussing coloured stones, we typically refer to the ‘Big Three’ – sapphires, rubies and emeralds. While some other gems are becoming more widely recognised in their own right, such as spinel, topaz and Padparadscha sapphires, it is still these main three that attract the most attention – and the highest prices. Their desirability lies in five principal categories: colour, durability, rarity, lack of treatment, and design.
Colour
The industry nomenclature of describing the colour of rubies, sapphires and emeralds goes far beyond simple ‘red’, ‘blue’ and ‘green’. One will often hear references to the ‘intense velvety blue’ of Kashmir sapphires, the ‘violety cornflower tint’ of Ceylon sapphires, and the ‘warm bluish-green’ of Colombian emeralds.
Specific colour terms have become so important in grading these stones as the best of the best that even gemmological laboratories can contain references in their reports on the ‘Pigeon Blood’ red colour of the top Burmese rubies.
Some organisations have attempted a colour grading system for sorting coloured gemstones – similar to the procedure used to grade diamonds – but the sheer range of numerous hues, tones and saturations make this an extremely challenging task.
Durability
While diamond is the hardest known material in the world, the Big Three do not fall far behind. Mohs scale of mineral hardness is used to measure the resistance of gems to scratches and scrapes. With diamond at number 10, sapphire and ruby come a close second at 9, and emerald coming in at a high 7.5. Not only do these gemstones look wonderful, but they can also withstand the inevitable knocks and scuffs of everyday wear!
Rarity
The fact that many of the mines, which produce the best-quality rubies, sapphires and emeralds, are now closed is one of the main driving forces behind the recent price increase for these gems. There simply isn’t the supply available to meet the growing demand! For example, the Kashmir mine that produced some of the world’s most exquisite and highly-prized sapphires was only accidently discovered after a landslide in the late 1880s, with the majority of the stones mined in a five-year period lasting until 1887. Large gem-quality rubies, sapphires and emeralds from other mines in Burma, Sri Lanka and Colombia are extremely rare and scarcely discovered.
With the growing consumer desire for the colour and liveliness of these gemstones, other regions in the world are stepping up to the challenge of meeting this demand. In the near future, we expect to see an increased number of stones from other areas that also produce beautiful gems, such as Mozambique rubies, Zambian emeralds and the continued supply of Sri Lankan sapphires.
Lack of Treatment
It is widely accepted that the majority of rubies and sapphires are subjected to some form of heat or chemical treatment to improve their colour and clarity. It is believed that around 95% of the world’s rubies and sapphires are treated in this way, with some estimates going so far as to propose that only 0.5-1% of these gems are free from any treatment. Therefore, untreated stones are considered exceptionally scarce.
This becomes more pronounced when we look at emeralds, which naturally contain many inclusions and are therefore commonly treated at the mines and cutting centres with oil to conceal their cracks and fractures. The rarity of untreated emeralds becomes apparent when we look at recent auction results: in April 2014, the Fine Jewellery auction at Bonhams London featured a ring set with a step-cut emerald weighing 10.49 carats, which was Colombian and free from any indications of treatment. The ring sold for £362,500 against a pre-sale estimate of £150,000-200,000.
Design
Big jewellery houses have long used these three gemstones within their most exquisite and famous designs. Jacques Cartier, the youngest of the three Cartier brothers, made frequent trips to India from 1911 to source their stones from Indian merchants and explore the intricate carving techniques employed by the Maharajahs’ lapidaries.
The partnership of exceptional untreated gemstones with period jewellery designs by these houses can command remarkable prices. In December 2014, Bonhams London sold an art deco ring set with a 5.34-carat step-cut Kashmir sapphire for £206,500 against a pre-sale estimate of £100,000-150,000, and a ring by Van Cleef & Arpels from 1923 set with a 13.34-carat sugarloaf cabochon Burmese ruby for £350,500, which was originally estimated at £80,000-100,000.
With sales such as these at auctions, the jewellery market can certainly look forward to a colourful future of these gems, giving the ‘King of Gems’ diamond a run for his money!
Sophie joined Bonhams in 2013 as a Specialist in the Jewellery department and is based at their New Bond Street headquarters. Prior to joining Bonhams, Sophie worked for an international jewellery and gemstone company since 2009, after working in PR and Communications in Beijing and London. Sophie gained a degree in Theology from the University of Bristol and holds gemmology and diamond grading diplomas from the Gemmological Association of Great Britain. She is also Reviews Editor at Jewellery History Today, the magazine of the Society of Jewellery Historians. Follow on Twitter at @Bonhams1793
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