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What to know before investing in coloured diamonds

Most people can appreciate the lustre of beautiful gems, but there’s no denying that the world of fine jewellery is cloaked in mystery — and oftentimes confusion — when it comes to diving into the finer technicalities and characteristics of gems (and we’re not just talking about the 4 C’s). To help polish our understanding, we’ve tapped Hong Kong jewellery expert Louisa Chan to answer some of our biggest questions about the world of jewellery. In this column, she breaks down the basics of colour diamonds, from the source of colour to the gradings and the common misconception of size.

Colour diamonds have popped onto every jewellery buyer’s radar in the recent decade. (Image credit: Tiffany & Co.)

In the recent decade, record-breaking auction results have widely publicised the rarity of colour diamonds. Though now on every jewellery buyer’s radar, few comprehend their occurrence as compared to traditional white (colourless) diamonds. It is not uncommon that clients feel ‘deceived’ when they’re shown the true colour of a pink diamond and at times thwarted when it’s revealed to them the market price of a blue diamond of just over two carats.

What are the reasons for the deviation between public perception of colour diamonds and reality? Let’s take a closer look at the common myths of both colour and size. 



Diamonds could be naturally imbued with colours such as yellow, pink, blue, green, orange, purple and red, which is caused either by chemical impurities or defect in their lattice. For example, the brownish and yellowish hue in a diamond comes from nitrogen, blue from boron, and it is generally accepted that structural defects in the crystal structure are the reason for the pink colour to occur. With that said, a top-grade red diamond won’t display the same red as rubies, and a superb blue diamond looks nothing like sapphires.


GIA gradings

Similar to the 4Cs that white diamonds are known for, GIA has a set of parameters to grade colour diamonds. With the exception of the colour red, the optimal balance of tone and saturation will earn them the Fancy Vivid grade, followed by Fancy Intense, Fancy, Fancy Light, Light, Very Light. (If this sounds confusing, take Fancy Vivid as ‘D’, Fancy Intense as ‘E’, so on and so forth.) It is important to note that every grade represents a range. There will be E-colour diamonds that are whiter and closer to ‘D’, others will be less white and closer to ‘F’. This may be less obvious for white diamonds, but when it comes to colour diamonds, for example, a Fancy Intense Pink that almost got graded Fancy Vivid has a more significant and visible pink hue than that of a borderline Fancy Pink.


A common trick to be aware of

Truth be told, any untrained eye will find the colour of an unmounted Fancy colour diamond rather difficult to see, many may even say they appear to be colourless. Unfortunately, only on very rare occasions do diamond roughs possess a colour intensity strong enough to realise a Fancy Vivid or Fancy Intense colour faceted stone, therefore it is common practice for jewellers to colour the backing of mountings to enhance a natural colour diamond’s beauty, and subsequently increase the saleability of lower-grade colour diamonds.



The general public, who readily accept these beautified products and are fed images of superb specimens purchased by the world’s leading collectors and tycoons, develop an almost distorted view on what a colour diamond should look like in real life.

Indeed, wonders in nature that exhibit pure and intense colours are so scarce that even if you have the means and are willing to wait, it is highly unlikely that you would behold a 15-carat Fancy Vivid Blue diamond or a 5-carat Red diamond in your entire lifetime.


The public’s perception

Marketing campaigns instil in our mind that any worthy engagement ring should hold a diamond of at least one carat. White diamonds of 2 to 5 carats are generally considered precious but not unheard of. Sometimes we read in the news that celebrities own white diamonds that weigh over 10 carats, and the uber-wealthy can afford rocks that are over 20 or 30 carats. However, this concept does not apply to colour diamonds.

The 14.62-carat Oppenheimer Blue was the largest and best quality Fancy Vivid Blue diamond ever to appear at auction.

In 2016, ‘The Oppenheimer Blue’, an emerald-cut Fancy Vivid Blue diamond that weighed 14.62 carats and fetched US$57.5 million, was the largest and best quality blue diamond ever to appear in auction. In the same year, the Aurora Green, a Fancy Vivid Green diamond weighing 5.03 became the largest Fancy Vivid Green diamond ever sold at auctions. Just last year, ‘Pink Legacy’ set a new record for the price paid per carat for a pink diamond at auction. It weighed 18.96 carats.

The Pink Legacy, a Fancy Vivid Pink diamond of 18.96 carats, set a new record for the price paid per carat for a pink diamond at auction in 2018.

All of the above-mentioned colour diamonds are considered exceptional and unbelievably rare specimens that only a very niche group of collectors could afford and appreciate. These examples also give us a sense of limit when it comes to the size of diamonds of various colours. Top-tier colour diamonds generally come in small sizes and quantities. The higher you go along the colour grading scale, the more difficult it is to find stones that are of substantial weight. And by substantial I mean anywhere from 1 carat to a few carats.


A final note to remember

Consumer products nowadays are so abundant we tend to forget that every diamond represents the marriage of miraculous happenings in nature and human craftsmanship. The Earth is our provider of the most amazing palette of colours, and as intelligent as humans are, we are here to discover and imitate.

This article first appeared on Lifestyle Asia Hong Kong

Louisa Chan

Originally trained as an architect and translator, Louisa incidentally entered the world of high jewellery when she was presented with an opportunity to work in auction business. She is currently a Jewellery Specialist in an international auction house and also an avid collector of vintage costume jewellery.