A Guide to Blue Diamonds

blue diamond guide

Welcome back to the Diamonds Hatton Garden blog where we bring you the latest from our Hatton Garden Jewellers. Following on from our series on natural fancy coloured diamonds, we turn to the beautiful fancy coloured blue diamond in our new guide to these incredibly beautiful and rare stones.

How are blue diamonds formed?

Natural fancy coloured blue diamonds are diamonds that are naturally formed under immense pressure deep in the Earth and have a range of blue colours or hues. As the diamond is formed the presence of Boron causes the diamond to change colour and receive the wonderful range of blue hues and tones that make these rare gemstones so incredibly prized.

blue diamond guide

Where are blue diamonds found?

One of the rarest of all fancy coloured diamonds, blue diamonds are found in three specific locations – Australia, South Africa and in parts of India. Blue diamonds, in particular, command large prices both in private sales and at auction due to their rarity and, given that they are only found in three places on Earth, they are incredibly rare!

How rare are blue diamonds and what do they cost?

Out of all fancy coloured diamonds, blue diamonds are the rarest and most expensive – excluding fancy coloured red diamonds. Fancy coloured blue diamonds are only found in three sites across the World – Australia, South Africa and parts of India. As with other fancy coloured diamonds, the more intense the colour saturation the rarer and more expensive the diamond. Typically speaking, blue diamonds are usually smaller on the carat sale meaning that blue diamonds above the carat weight of 2-3 are very uncommon – another factor in their price. Sue to their rarity, blue diamonds are favoured by collectors and investors. It has been estimated that for every 1 carat of jewellery quality blue diamonds there are some 150 Picasso paintings! 

Prices vary for blue diamonds depending on their colour intensity, size and shape – howiever, on average a light blue diamond of around 0.3 carats costs around £12,500GBP. Within diamonds, there does not exist an economy of scale and if we move up the carat weight the price does not increase in a linear fashion. For example, a 0.5 carat blue diamond of the same intensity will cost around £22,000GBP. He deeper and more vivid colours command even higher prices and as the colour intensity and size increase so do the prices and it is not uncommon to see carat prices between £100,000GBP and £200,000GBP.

How to buy blue diamonds

Buying a blue diamond can be one of the most enthralling experiences that one can have. The rarity, brilliant colours and story of the diamonds make an intoxicating mix. Read more in our guide how to buy blue diamonds  

How are blue diamonds graded?

Blue diamonds, like all fancy coloured diamonds, are graded on their colour scale as which often mentions a mixture of another two or three colours which provide the overall colour of the diamond. The rarest of all blue diamonds are those which have a pure blue colour and other colour combinations such as grey-blue and green-blue are more common. The certificate that accompanies the diamond will describe the colour of the diamond and mention if there are secondary or tertiary colours within the mix. Not only is the colour itself graded but the intensity of the colour is an important factor which one must consider when purchasing a fancy coloured diamond. The colour intensity is the same across all fancy coloured diamonds and is as follows: faint, very light, light, fancy light, fancy, fancy intense, fancy deep and fancy vivid. The further down the list (closest to fancy vivid) the rarer the colour and thus more expensive. 

blue diamond colour spectrum

What are the most expensive/famous blue diamonds?

Blue diamonds, due to their price and rarity, almost seem mythical in nature. The most expensive and famous ones even more so. We have chosen two of the most prized fancy blue diamonds ever to inspire you and to set your jewellery dreams off! 

In 2015, the 12.03-carat ‘Blue Moon’ diamond was sold for over $48 million at auction. At $4 million per carat, the Blue Moon diamond is one of the most expensive diamond per carat ever sold. The diamond was discovered in 2014 at the Premier mine in South Africa and demonstrates the highest possible colour grading for blue diamonds. This means that it is free of any inclusions or scratches. The Gemological Institute of America (GIA) has even labelled the Blue Moon Diamond as internally flawless, a perfect clarity grade.

The Blue Hope Diamond might not be labelled as flawless, but it is one of the most stunning gems in the world. It is a 45.52-carat stone that was found in India. Folktales say the diamond has been cursed for being stolen from the eye of a scared Hindu Goddess Sita. An assortment of owners through history have experienced tribulation while owning this gem. Surprisingly, this wouldn’t be the first time a diamond was infamous for being stolen from a religious statue. Today, the gem is part of the National Gem Collection and holds an estimated value of $250 million.

As one of the UK’s leading suppliers of loose diamonds, Diamonds Hatton Garden are on hand to assist you with all of your diamond jewellery needs. Contact our Hatton Garden jewellers today via info@diamondshg.co.uk or on +44 7951 060238to book your appointment.