How To Choose a Coloured Diamond

| 4 min read

If you think of a Diamond, you probably think of a Colourless stone. But did you know that there is a huge array of colours of Diamonds naturally created by Mother Nature herself? So how do you choose a great Coloured Diamond? Use this handy guide to help you pick the perfect gem for you.

Coloured Diamonds have been gaining popularity in recent years. Popularised by the likes Mariah Carey, Jennifer Lopez, and Heidi Klum, a Fancy Coloured Diamond is as eye-catching as it is rare. Follow these useful tips to make sure you get your perfect gem.


Pick a budget and stick to it. It is very tempting to spend more than you wanted, but it is worth shopping around to make sure you’re getting a great deal.

I’m going to mention lots of money saving tips in this blog, as Coloured Diamonds are incredibly rare and can be incredibly expensive.


Coloured Diamonds are judged chiefly for their colour.

Coloured Diamonds gain their colour from impurities in the gem – either Boron, Nitrogen, Hydrogen, natural Radiation, or in the case of Pink or Red Diamonds, by an unusual alteration in the crystal structure. Black Diamonds are thought to be from outer space!

These are the colours of Diamonds you might come across (from least rare to rarest):

  • Brown
  • Fancy White
  • Yellow
  • Blue
  • Green
  • Black
  • Pink
  • Orange
  • Purple
  • Red

Whereas Colourless Diamonds are graded by how little colour they have, the opposite is true of Coloured Diamonds.

The most prized colours are deep in tone and richly saturated.

Most Diamonds are Yellow or Brown, but the majority will be at the low end of the D-Z Colour Scale. Once they have more colour than this, they are ‘Fancy Coloured’ and there is a significant price jump.


The rarest naturally Coloured Diamonds are incredibly expensive – regularly hitting $1 million per carat at auction. Most of us don’t have this kind of cash!

Luckily, with a little help, Diamonds can be enhanced to show these colours. Natural gemstones can have their colour improved with the following treatments:

• Irradiation (sometimes followed by annealing)

• High-pressure high-temperature treatment

These treatments mimic the work of Mother Nature herself, resembling the natural processes of heat, radiation, and pressure. These are always regarded as genuine Diamonds, and will always command higher prices than synthetics and simulants. We will always let you know what treatments your Diamonds may have had.


The way a Coloured Diamond is cut can have a significant impact on how the colour looks. Cuts are often chosen to emphasise the Diamond’s colour. Some of the best cuts to bring out the colour in for Coloured Diamond are:

  • PEAR
  • OVAL

Round Brilliant cuts, which are incredibly popular for Colourless Diamonds, aren’t one of the best cuts to bring out colour. If you are lucky enough to get hold of a Round Brilliant cut Coloured Diamond with rich colour, you have an exceptionally unusual treasure.


Like Colourless Diamonds, Coloured Diamonds are judged for their clarity, using the following scale:

Here at Gemporia, we usually recommend I1 graded Diamonds, as you can’t see the difference between any of the higher grades to the naked eye (but your wallet will notice the difference!).

It is worth bearing in mind however, that even Coloured Diamonds fetching millions of dollars per carat often have inclusions that are easy to see to the eye. When it comes to Coloured Diamonds, colour is by far and away the most important thing!

Carat Weight

When it comes to size, then bigger is obviously better. Diamonds range from fractions of a carat to hundreds of carats, but the larger stones have a larger premium, as they are rarer. If you double the size of a Diamond, the price would more than double, as the rarity increases.


When you are buying any gemstone, particularly if you are looking to spend a lot, it is important to make sure that the item comes with a certificate. The certificate should have, as a minimum:

  • What the gemstone is
  • The carat weight
  • If it is in a setting, what the metal is
  • What treatments the gem might have had

Additionally, make sure you know the seller’s returns policy, and that their Diamonds are ethically sourced.

Do You Love It?

I think this is so important! In the end, it all comes down to this question. Nobody’s opinion is as important as yours. Yes, it is worth checking what other prices are on the market, and being sure that you know what you are getting, but… if you fall in love with a gemstone it is probably the gemstone for you. Gemstones are unique, they have a character that we can fall in love with, and no other gem is going to be exactly the same. If you love it, go for it!

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