
JANUS JEWELS’ GUIDE: BUYING & SELLING COLOURED DIAMONDS
FANCY COLOURED DIAMONDS EXPLAINED
How are natural coloured diamonds made? Are coloured diamonds a good investment? And why are red diamonds so expensive? Discover all this and more in our Fancy Coloured diamond online guide.
Once upon a time — back when diamonds were a girl’s best friend — the only diamonds that counted were colourless ‘white’ diamonds. But that’s brilliant marketing for you. In truth, diamonds range in colour from milky white diamonds to black diamonds. And incredibly, some natural coloured diamonds are worth way more than the most dazzling, colourless diamond ever could be.
HOW ARE COLOURED DIAMONDS MADE?
The finest, colourless Type IIa diamonds consist solely of carbon atoms. They have no defects or impurities within their crystalline structure, and it’s this purity that gives them their fabulous colourless sparkle. Coloured diamonds begin life the same way. But, at some point during their formation, something happens to change that. For example, most naturally coloured diamonds also feature trace elements of chemicals such as boron, sulphur or nitrogen. Essentially impurities that altered the diamond’s carbon structure during its creation, these ‘trapped’ chemicals can create diamonds of varying blue, green or yellow shades, respectively.
WHAT ARE THE BEST COLOURED DIAMONDS?
Impurities or defects within a diamond’s atomic structure strongly influence a stone’s colour and can combine to create visually stunning colourful jewels. The most valued of these are called fancy colour diamonds. Only 1 in 10,000 diamonds has a fancy colour.
Whether coloured or colourless, a diamond’s perceived beauty and worth are based on the 4cs: carat, cut, colour and clarity. But while a ‘white’ diamond’s value increases based on its absence of colour, with fancy colour diamonds, hue, tone and saturation of colour are vitally important. The stronger, purer, and more vivid a gem’s colour, the more valuable it invariably is. The most highly sought-after fancy colour diamonds are:
- Yellow
- Orange
- Pink
- Blue
- Green
- Red
Each of these colour types refers to the diamond’s primary colour, but most coloured diamonds also have a secondary tone. That’s why you’ll often see stones described as, say, Fancy Vivid Purple Pink, or — as with this necklace’s stunning swallowtail centrepiece — Fancy Orangy Pink.


PINK DIAMOND BUTTERFLY NECKLACE
GBP 22,000
EnquireA delicate and feminine jewel; the butterfly’s minimalistic form contrasts delightfully with the striking central stones. Created using exceptional white diamonds, platinum and 18K rose gold; the GIA certified 0.59 carat, Fancy Orangy Pink, pear shape diamond ‘swallowtail’ moves freely to maximum effect. A simple joy.
ARE ALL NATURAL COLOURED DIAMONDS EXPENSIVE?
The term rare is used and abused by today’s jewellery trade, so don’t fall for a good sales pitch! Coloured diamonds make up less than 0.1% of ALL mined diamonds: so, generally speaking, they’re exceedingly rare. However, some hues — like grey, brown and some paler shades of yellow — are more common and less popular than even colourless stones. As with any commodity, supply and demand dictate price; so, these colours are relatively affordable compared with their classic colourless equivalents.
The finest Natural Fancy Colour diamonds are those infused with pure saturated colour. Seldom ever found in nature, chances are they won’t rock up at your local village jeweller. These unique jewels are rarer than rare and come with prices to match.
So, how do the main colours rate when it comes to price per carat?
- Relatively affordable: Fancy Yellow Diamonds.
- Investment Tier 1: Intense and Vivid Yellow Diamonds and Orange Diamonds.
- Investment Tier 2: Pink, Green and Blue diamonds
- Billionaire territory: Red diamonds

YELLOW DIAMONDS
The most widely available colour, yellow diamonds account for some 60% of all coloured diamonds. A yellow diamond’s colour results from nitrogen impurities: these absorb blue light, causing the diamond to appear yellow. Ranging in shades from the palest yellow through to an intense Canary Yellow, these stones have become increasingly popular for ‘alternative’ engagement rings.
BLUE DIAMONDS
Boron impurities cause a blue diamond’s stunning natural colouration. Incredibly, only the tiniest trace amount is required: in a natural Type IIb blue diamond, the boron concentration is approximately just 0.5 parts per million. The most famous Blue diamond is the Hope Diamond, a fancy dark grayish-blue stone of 45.52 carats, once owned by King Louis XIV of France. The finest blue diamond ever offered at auction is the 14.62 carat, vivid blue Oppenheimer Blue. A ‘once in a lifetime’ stone; it sold in 2016 for a then-world record price of $57.5 million (including commission and fees).

GREEN DIAMONDS
Green diamonds are caused by natural radiation emitted near the diamond crystal during its formation. It’s incredibly unusual to find a green diamond with even colouration. The best known is the magnificent 41 carat Dresden Green. With a documented history dating back to 1726, it’s thought to be the largest, finest naturally green diamond that’s ever existed.
RED & PINK DIAMONDS
How pink and red diamonds get their unique colour is still up for debate. Like colourless diamonds, red and pink diamonds consist solely of carbon, so impurities don’t cause their colour. The most popular view is that a dislocation in the diamond’s atomic structure occurs during formation. This is known as plastic deformation, and it results in diamonds of varying shades of pinks and reds.
In April 2017, The Pink Star, a 59.6 carat diamond, became the most expensive gem ever auctioned when it sold at Sotheby’s for $71.2 million!
The rarest, most valuable diamonds of all, though, are red diamonds. The discovery of a red diamond is such an unusual event that between 1957 and 1987, the Gemological Institute of America (GIA) wasn’t asked to grade a single one! Although by far the most expensive diamond per carat, most red diamonds are less than half a carat in size. Exceptionally rare, only thirty true red diamonds are thought to exist.
The most revered red diamonds are those graded Fancy Red: a pure, ruby red, with no secondary modifying colours at all, these stones are exceptionally rare. The world’s most famous Fancy Red diamond is the Moussaieff Red. A 5.11 carat, internally flawless, triangular brilliant-cut diamond, it’s the largest Fancy Red natural colour diamond ever graded by the GIA. An astonishing stone, today it’s worth at least $20 million.

THE GIA FANCY COLOUR DIAMOND GRADING SCALE
Fancy coloured diamonds come in a range of colour strengths. Grading them is a hugely specialised science: as each diamond is unique, there’s no handy Pantone colour chart to refer to! The world’s leading gemstone authority, the GIA, uses this scale for grading fancy coloured diamonds:
- Faint
- Very Light
- Light
- Fancy Light
- Fancy
- Fancy Intense
- Fancy Vivid – the best of the best
- Fancy Dark
- Fancy Deep
Confusingly, the scale doesn’t entirely reflect the order of value. Fancy Dark and Fancy Deep diamonds have a darkness/inkiness that detracts from their brilliance. Although often extremely attractive stones with a strong, vivid body colour, their slight dullness marks them down to below the best of the best and reduces their worth. So, no matter its colour, a good quality Fancy Intense diamond with no undertone will always be more valuable than its Fancy Dark or Fancy Deep counterpart.


Whatever a diamond’s colour, never ignore its cut. There are some wonderfully coloured but frankly ugly stones that, on paper, are worth a fortune. Ideal gems for when you’d rather put your money in rocks than stocks: they make great investments but (whisper it) dreadful jewellery. Remember, the better the cut, the better the diamond.
WHY YOU SHOULD BUY GIA CERTIFIED DIAMONDS
It takes years to learn all the factors that determine a coloured diamond’s value. So, if you’re thinking of buying coloured diamonds, either as loose stones or as jewellery, don’t just rely on an auction catalogue listing or some sales bumf. You need to be sure that they are natural stones that have not been treated. And you need an expert to tell you that, so seek professional advice. At Janus Jewels, we have the know-how and industry contacts to source the best stones for your money. To find out how we can help you, give us a call.
Whether you seek our assistance or not, it’s vital that any stone you buy has a GIA certificate. The gold standard (yes, we know) of gemstone certification, a GIA certificate will confirm that a stone is of natural colour, along with its grade of colour and that it’s not been treated in any way. Man-made (lab-created) diamonds — especially small pink and yellow stones — are increasingly being passed off as the real thing by fraudulent dealers. Don’t get caught out. Get expert advice and get a certificate.
FANCY COLOUR DIAMOND ENGAGEMENT RINGS
Colourless or near colourless diamonds account for some 85% of engagement rings. So, to stand out from the crowd, coloured diamonds should be your go-to gems. After saying yes to Ryan Reynolds, Blake Lively donned a light-pink oval cut diamond. And Ben Affleck and Jennifer Lopez sealed their engagement with a multi-million dollar 6.1-carat pink diamond engagement ring, designed by Harry Winston. The first time that a mega-money coloured diamond had hit the headlines, it caused pink diamonds’ popularity to soar. Meanwhile, Heidi Klum, Paris Hilton and Kelly Brianne Clarkson all rocked yellow diamonds.
But you don’t have to be Hollywood to add a splash of colour to your life. With Janus Creations’ bespoke service, you can have the engagement ring of your dreams using any coloured diamond of your choice. The only thing holding you back is your imagination. So, call us today to find out how we can make your forever jewel a reality.

ARE FANCY COLOURED DIAMONDS A GOOD INVESTMENT?
Over the past decade, the value of fancy colour diamonds has risen rapidly. Once considered a bit quirky, now they’re firmly established as collector and specialist stones. At Janus Jewels, we see our more discerning clients choosing coloured diamonds for their investment potential and as alternative engagement rings.
Whatever your reasons for buying coloured diamonds, choose wisely, and your jewels will only increase in value. For, unlike white diamonds, fancy coloured diamonds are extraordinarily rare. It’s this limited stock, compounded by increased popularity, that’s driving prices ever higher. With traditional financial investments offering historically low returns, wise investors are buying coloured diamonds as diversified assets and stockpiling them. With fewer fancy diamonds coming onto the market, specific sizes and colours are becoming more difficult to source. Without a doubt, coloured diamonds are the ‘hot’ gemstones of the 20s.
GET EXPERT HELP BUYING & SELLING COLOURED DIAMOND JEWELLERY
Whether you long for a specific stone for its beauty or as an investment, we can source the coloured diamond of your dreams. Just tell us what your heart desires, and we will find it.
We can help, too, if you’re tired of your coloured diamond jewellery or are looking to realise an individual gem’s worth. Whether you sell at auction or via our private network of serious collectors, we’ll ensure you get the best price for your jewels.
For free advice and appraisals, get in touch today.