Coloured diamonds, like colourless diamonds, are created naturally from carbon deep beneath the Earth’s surface at temperatures greater than 1000 degrees Celsius over millions of years. Changes in their chemical structure as they form, however, are what give coloured diamonds their gorgeous, unique colours, altering the way they reflect light and the colour our eyes see. These little variations are extremely rare, occuring in only 0.1 percent of all diamonds, yet they can result in stunning colours covering the entire colour wheel, including pink, purple, red, blue, yellow, brown, and every colour in between, all created naturally.
How are Coloured Diamonds Priced?
Cut, clarity, carat, and colour are used to grade and price coloured diamonds. The pricing rules for colourless diamonds apply to cut, clarity, and carat, but colour grading is very different. There are roughly 30 base colours to choose from, with over 200 different colour combinations possible. A laboratory grader analyses the base colour to determine the color’s specific name and any secondary colors. The colour of a green diamond with touches of blue, for example, is described as “bluish green.” In order to determine the Fancy Colour of a diamond, a grader will look at the hue, tone, and saturation of the colour. From least to most saturated, this grading is decided by the colour intensity, and is classed as faint, very light, light, fancy light, fancy, fancy intense, fancy vivid, fancy dark, or fancy deep. The diamond will be more expensive if the colour is deeper and more intense.
Red Diamonds
Only 20-30 red diamonds exist in the world, making them the rarest of all coloured diamonds. They receive their lovely red colour through a rare process that alters the crystal structure of the diamond during formation, causing light to travel through it differently than colourless diamonds. Due to the rarity of this process, red diamonds are often only half a carat to a carat in size. Still, their rarity and their intense, crimson color make them the most expensive per carat of all the colored diamonds, and on average will cost over $1 million per carat. The largest red diamond ever sold, weighing 5.11 carats, was bought for $8 million, at $1.6 million per carat. You can shop these rarities at Blue Nile, who offer an expansive selection of colored diamonds for you to choose from.
Blue diamonds
The element boron, which replaces some of the carbon in the diamond crystal structure and can generate anything from a tinge of blue to a deep, rich blue colour in the diamond, is responsible for its blue colour. Only a few mines in the world will mine blue diamonds because they are so uncommon, and they are located in South Africa, Australia, and India. Although they are less rare than red diamonds, they can grow to be considerably larger and are frequently sold for more, despite costing less per carat. That doesn’t mean they aren’t expensive; a 1 carat medium toned blue diamond can cost up to $200,000. And, like other coloured diamonds, they get more expensive as the colour and carat size grow. The most valuable blue diamond ever sold was a 14.2 carat fancy vivid blue diamond that sold for $57.5 million at $3.9 million per carat. The Hope Diamond, which is currently kept at the Smithsonian and weighs 45.2 carats and is estimated to be worth $250 million, is the blue diamond that truly takes the cake. These blue gems can be found at James Allen, which has a large selection of coloured diamonds and 360-degree views of each one.
Pink Diamonds
Argyle diamonds, a type of pink diamond, are among the rarest coloured diamonds, and are mostly mined by one single mine in Australia, the Argyle mine. Pink diamonds can be more expensive than blue diamonds, despite their same rarity. This is owing to the tremendous demand for their charming, romantic pink tint. These gems are likewise a mystery: gem experts don’t know what causes their colour. They are constructed of pure carbon, much like colourless diamonds, but have a unique crystal structure that reflects the beautiful pink colour that our eyes see. Pink diamonds mined outside of the Argyle mine are less expensive than Argyle pink diamonds, but they can still break your bank!
Pink diamonds, like other coloured diamonds, have a wide range of prices per carat due to changes in size, colour, and clarity. As a result, the price of a single carat pink diamond can range from $10,000 to over $700,000. The Pink Star, a 59.6-carat pink diamond that sold for $71.2 million in 2017 at $1.19 million per carat, is the most renowned pink diamond.
Yellow Diamonds
Yellow and brown diamonds are the most prevalent coloured diamonds, accounting for more than half of the coloured diamond industry. They are still extremely rare, but their low price and eye-catching colour have made them the most sought-after coloured diamonds. Yellow diamonds receive their colour from the element nitrogen, which absorbs blue light and reflects a beautiful yellowish colour. They are frequently discovered with a variety of secondary colours, but Canary Yellow Diamonds, a typical term for pure fancy yellow diamonds, are the most valuable and sought after. Yellow diamonds are less expensive per carat than other coloured diamonds since they are less rare. Light yellow diamonds can even be less expensive than colourless diamonds of same size. On average, a yellow diamond with good clarity and colour will cost $3,000-5,000 per carat. The price of a fancy vivid yellow diamond can range from $8,000 to $16,000 per carat. The Graff Vivid Yellow diamond, weighing a staggering 100.90 carats and selling for $16.3 million in 2020, was the most expensive yellow diamond ever sold.
Lab-Grown Coloured Diamonds
Because coloured diamonds are rare in nature, they are quite expensive, but lab-grown coloured diamonds can be a more inexpensive option. Lab-grown diamonds are identical to mined diamonds, however they are created in a lab at high temperatures rather than deep underground. A synthetic 1-carat blue diamond, for example, will cost on average $8500, compared to $200,000 per carat for a mined blue diamond. In addition, lab-grown diamonds have a smaller environmental impact and are guaranteed to be ethically sourced, making them a more affordable and sustainable option. Blue Nile has a large selection of lab-grown diamonds that may be used to create beautiful and cheap jewellery.
