The allure of coloured diamonds

Bathed in the winter sun, the soft light it gave off was mesmerising and quite unlike anything we had seen before, and its strange beauty got us thinking about colour diamonds beyond the more usual pink, blue and yellow, and those that contain a combination of more than one colour.

In the swirling gases and forces at work deep in the body of our young planet, millions of years ago, nature created diamonds in all manner of colour combinations. Clear whites, pure yellows, pinks and blues have traditionally been the most sought-after, but colour diamonds with a secondary moderator hue, such as a green, grey, yellow, purple or blue, are stepping out of the dark.

A visit to Bond Street’s top diamantaires reveals that there is indeed a quiet chromatic revolution going on.  Only a decade ago, straight-up top-grade pink, blue and yellow diamonds were the only acceptable colour solitaire to flash to show both sophistication and deep pockets. But it seems we are warming to more adventurous choices in our search for something truly different.

Coloured or fancy diamonds – as the Americans refer to any diamond that exhibits colour beyond the Z range, or diamonds that exhibit any other colour face-up – are graded by their dominant colour, such as pink, yellow, blue or green, and then by the secondary or moderating colour.

The authoritative Gemological Institute of America (GIA) created the useful circular chart above to shows how the different colours flip through the spectrum, from, say, Orangy Red to Reddish Orange. In the introduction, editor John M King explains: “For most people, colour is an intuitive response rather than a true knowledge of the systematic ordering of colour appearances. Both, however, are crucial when the romance of colour also becomes the business of colour.”

But not all colour diamonds are equal, and some colour combinations work better than others. It is generally accepted that purplish pink is a pretty combination, as is blue green or green blue.  What the diamonds we have selected all have in common is that they are all an appealing balance of hue, tone and saturation.

The complexity of grading and pricing these stones has been both their ally and their downfall as valuing them is something of a minefield. While whites have well-respected online price charts that are constantly updated, there is no reference for orange and green diamonds, never mind the variations of moderating colours.

But what is clear is that the pure colours, such as green or orange, command higher prices, and the majority of auction record breakers are single colour top-of-the-range Fancy Vivids, such as the 15.38 carat Unique Pink that sold for $31.5 million or the 14.62 carat Oppenheimer Blue, purchased for $57.5 million.

Much like the art market, prices can be arbitrary, with deals taking place behind closed doors and no auction reference prices to rely on. But we know from the experts on Bond Street that a 3-carat Vivid Orange diamond would sell for say $7 million, while a Vivid Yellowish Orange would possibly only fetch $2 million. 

Pricing issues aside, the grande dame of diamonds on Bond Street, the formidable Mrs Moussaieff – or Mrs M to those who know her – declares: “Unusual coloured diamonds are certainly becoming more sought after as people become far more educated about diamonds. 

Clients from the Far East and the Middle East are buying anything from Grey to Yellowish Green or Greenish Yellow.  They also love Orangey Yellow and Orangey Pink.  The most unusual diamond I have ever seen was a beautiful Violet colour.”

Colour-diamond expert Louise Kruger offers advice: “Coloured diamonds is a specialised category, and you need specialist advice to know your way through the overtones. You can make the best investments possible with colour diamonds, but also the worst ones. ‘Beauty is in the eye of the beholder’, as they say, so if you fall in a love with a specific colour, make sure you are paying its real value and not your perception.”

The Jewellery