Diamonds come in all shades of colour. However the majority of jewel-quality diamonds range from almost colourless to a very light yellow or brown. These account for approximately 95% of polished diamonds.
For centuries, the perfect diamond has been described as colourless (white). Nevertheless diamonds come in all colours of the rainbow including yellow, orange, red, blue and even black. Intensely coloured diamonds, known as fancy colour diamonds, are extremely rare. Such stones are very highly valued, simply because of our fascination with freaks of nature.
Fancy Colour Diamonds: Key facts
Only about one in 10,000 (0.01%) diamonds is a fancy colour diamond.
Fancy colour diamonds are extremely valuable due to their intense colour.
Fancy colour and colourless (white) diamonds often originate from the same mine.
can fetch from 5 to 100 times as much as colourless diamonds.
Blue and red
diamonds are the rarest of the fancy colour diamonds.
Yellow and brown
are the most affordable and less rare of coloured diamonds. They fetch around one third of the price of white (or colourless) diamonds.
What causes colour in diamonds?
The creation of diamonds
Diamonds are a crystallised mineral that originate from very pure carbon atoms. These carbon atoms form into a crystal more than 150 km beneath the surface of the earth. The formation occurs under enormous pressure combined with extreme temperatures. Diamonds take millions of years to form.
The transportation of diamonds to the earth's crust
During or after their formation, diamonds are brought to the surface of the earth with magma during volcanic eruption. This liquid rock that transports diamonds to the earth’s surface is known as kimberlite.
In rare cases such as the Argyle mine in Australia, the diamond-carrying stone is known as lamproite.
The source of colour in diamonds
During its formation, other atomic impurities can occur in the crystal structure of the diamond. These impurities absorb light from parts of the visible spectrum, hence resulting in various colour shades. The most commonly occurring impure atom in diamonds is nitrogen.
The Argyle fancy colour diamonds
An exception are the Argyle diamonds mined in Australia. These diamonds are very pure. The cause of their marvellous rare pink colour is a simply a freak of nature.
The Argyle mine was established as the first major diamond mining operation in Australia in 1983. At its peak, the mine produced over 42 millions carats of rough diamonds. This volume represents 40% of the world’s diamond production. A large proportion of the mined diamonds are small to brown to yellow. Only a limited amount of this production qualify as rare pink diamonds.
Grading of fancy colour diamonds
Similar to colourless (white) diamonds, fancy colour diamonds are also colour graded. However the grading scale is different than that of colourless diamonds, which ranges from D to Z. The majority of gemological laboratories use the following international standard to certify fancy colour diamonds:
[Fancy] [Intensity] [Hue] natural colour, e.g. fancy intense pink
Should you have any questions on fancy colour diamonds, our expert staff are available to help on 0845 548 9858.