More information on naturally coloured diamonds

Natural fancy diamonds are very exclusive and rare, even rarer than colourless diamonds. A true natural coloured diamond has been gifted to us by nature and can be found in a variety of colours, from pink to yellow to brown and even red. Fancy coloured diamonds are only to be found in very limited areas.

Only one in every 10,000 diamonds has a natural colour and is therefore called a fancy coloured diamond. Fancy coloured diamonds are purchased almost exclusively for the intensity and distribution of the colour of the diamond. Criteria considered when purchasing a white or colourless diamond, such as cut proportions and clarity, are less important when purchasing a fancy coloured diamond.


The cause for the colour in coloured diamonds varies from colour to colour. For instance, yellow diamonds owe their cheerful hue to the presence of nitrogen. Blue diamonds, on the other hand, contain boron, which causes a blue colour. The cause of pink and red diamonds' remarkable colour is unknown for certain, though speculations state that they are variations of the result of fractures in the crystal lattice. The rarer the colour, and the more intensely the colour shows, the higher the value. Yellow and brown diamonds are most commonly found, while red, blue, and green diamonds are among the rarest of all fancy colours.


Colour intensity, namely the deepness or richness of the colour, is the most important parameter when purchasing a fancy coloured diamond. The more intense the colour, the rarer and more valuable the diamond will be. Diamonds with lighter colour intensity levels such as faint, very light, light, fancy light, and fancy are more common than diamonds with the richer intensities of  fancy intense, fancy vivid, and fancy deep, and thus less in value.

All fancy coloured diamonds of BNT Diamonds are 100% natural, and not treated.

Below you can find some examples of different colours and intensities:

   Fancy pink-brown

   Fancy brownish pink

   Fancy light pink

   Fancy pink

   Fancy deep pink

   Fancy brownish greenish yellow

   Fancy grayish/greenish yellow

   Fancy light yellow


After colour grade, carat weight has the most impact on price for fancy coloured diamonds. One carat equals to 0.2 gram. The word "carat" comes from the "carob" seed, the original unit of measure for diamond traders. As the carat of a diamond increases, the diamond's price increases at an exponential rate because the rarity goes up like this. Fewer than one in one million mined rough diamonds are large enough to produce a polished 1 carat diamond. The diamond prices for fancy coloured diamonds rise exponentially with carat weight.



As diamonds are formed deep within the earth, under extreme heat and pressure, they often contain unique birthmarks, either internal (inclusions) or external (blemishes). Clarity grading goes from LC (loupe clean) or IF (internally flawless) to I3 (included). The higher graded on the clarity scale, the more precious and special, and the higher the price.
Due to the nature of fancy coloured diamonds, clarity is less important than it is in their colourless counterparts. This is true because inclusions tend to be masked by the diamond's colour.


Fancy colour diamonds are primarily cut to emphasize their colour. This contrasts with colourless diamonds, that are cut to maximize their sparkle or brilliance. While fancy coloured diamonds still exhibit brilliance, colour is the most important characteristic considered when they are being cut.


Shape refers to the overall outline of the diamond when viewed from the top (e.g. round, princess or cushion). A lot of fancy coloured diamonds are cut into non-common shapes to enhance their natural colour. Because of the rarity of fancy coloured diamonds, not all colours are available in any shapes at any given time.

If you are looking for a specific fancy coloured diamond, please contact our experts through or +32 3 201 24 90.

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