Green diamonds traditionally symbolise peace, tranquillity, growth and fertility. They are amongst the rarest and the most highly-valued natural fancy coloured diamonds available ranking alongside blue, purple, pink, and violet diamonds in terms of rarity value. However, due to the popularity of blue and pink diamonds they have become somewhat obscured, although in actual fact they are rarer and this is largely due to the way in which green diamonds are formed. Here we take a closer look at this most intriguing of the natural fancy coloured diamonds:
Diamonds are formed when organised carbon atoms are pressurised and bound together in the earth’s core. As we know colourless diamonds are chemically pure and structurally perfect. Whilst in comparison natural coloured diamonds are formed when impurities occur in the chemical bonding, or defects in the crystalline structure. However, green diamonds are the exception. They acquire their unique colour from an extremely rare process of natural irradiation that occurs where carbon deposits in the earth contain highly radioactive material.
A natural green diamond will be exposed to radiation over a period of thousands of years during its formation underground. The radiation, usually coming from uranium near the Earth’s surface, has the innate ability to displace carbon atoms in the diamond from their positions. This changes the stones ability to absorb and refract light which allows it to reflect the green colour on its surface. The longer the diamond is exposed to radiation, the more vivid the green colour becomes. The fact that these conditions have to be absolutely perfect for a green diamond to form is the reason that natural green diamonds are a genuinely rare occurrence and this is what makes this gemstone so intriguing.
There is however no reason to be worried about the levels of radiation in green diamonds. Because this process takes place underground over thousands of years the actual diamond is rendered harmless. The green colour does not contain harmful chemicals and is merely the green light being reflected on the crystal, and the diamond retains only the radioactive stains NOT the properties of radioactivity.
The majority of natural green diamonds are mined in Brazil, Venezuela and Zimbabwe
How are green coloured diamonds graded?
The Gemological Institute of America (GIA) has a special colour-grading system for fancy coloured diamonds including green diamonds. This takes into account the hue, tone and saturation of the rocks. The term ‘hue’ refers to the primary colour of the diamond, the tint which appears on the surface i.e., blue, red, green, yellow. ‘Tone’ refers to how light or how dark the colour is, with the faintest grade nearing transparency while the darkest leans to black. ‘Saturation’ refers to how heavy the colour appears on the stone. The more vivid, deeper colours are graded higher on the chart.
How is a green diamonds’ colour intensity measured for grading?
The longer a green diamond is exposed to radiation then the deeper into the gem the colour will have penetrated and this will also determine the hue. As green diamonds are less affected with impurities, it is often difficult to classify these diamonds according to colour and they can range from faint green to fancy deep green. Pure green diamonds are graded as follows: Faint Green, Very Light Green, Light Green, Fancy Light Green, Fancy Green, Fancy Intense, Fancy Vivid, and Fancy Deep. Those classified Fancy Vivid Green are the rarest as they hardly ever occur so making them the highest priced.
Very often green diamonds will also display two secondary colours these being blue and yellow. You will therefore often see them colour graded as yellow, yellowish, blue, bluish, brown, brownish, gray, grayish, gray yellowish, and grayish yellowish.
To establish the origin of colour green diamonds are always submitted to a gem laboratory. However even with today’s advanced technology it is not always possible for the lab to produce a satisfactory assessment. Most of them are not green all the way through and many will show green radiation blotches or stains on the surface which get polished away during the cutting process, which lead to a loss of colour. In these cases diamond cutters have to work their way around this in order to present the highest colour saturation in the best way. It is highly unusual for a stone to be evenly coloured all the way through, but they do occur.
To add to the intrigue, mystery and beauty of natural green diamonds some display another extremely rare phenomenon. This is their ability to change colour to suit their environment, hence the name given to this type of diamond – ‘Chameleon Diamonds’.
Chameleon Diamonds are a variety of natural green diamonds that normally possess a green colour but can change from brown to yellow dependent upon their exposure to light and heat. For example, when heated or kept in the dark, they can turn to bright yellow temporarily and as they cool down or are gradually exposed to light, they turn back to their original green hue. There is no exact explanation as to why this phenomenon happens and no other diamond possesses this ability which is the reason why Chameleon Diamonds are twice as rare and are highly sought-after by diamond enthusiasts. A very famous Chameleon Diamond is The Chopard Chameleon which is a 31.31 carat oval shaped diamond.
Famous natural green diamonds
As green diamonds are so rare, only a handful of them are ever found. Perhaps the most famous green diamond in the world is the ‘Dresden Green’. Believed to have been discovered in India in the 18th century this stunning green diamond weighs an amazing 41 carats. It is the largest the known natural green diamond to have been discovered and has a clarity grade of VS-1, which was received by the GIA in 1988 as uniquely its colouration is uniformly distributed throughout. It was acquired by Augustus, King of Poland and Elector of Saxony in 1742 and it remains on view in the Green Vaults in Dresden today. It sets the benchmark for all stones of its kind because its colour is natural and homogenous all the way through.
Also famous is the ‘The Ocean Dream’ whose name refers to its unique Fancy deep blue-green shade that resembles the crystalline image of a very, very deep ocean. It weighs 5.5 carats and was put on exhibition in the Smithsonian’s ‘Splendour of Gems’ exhibition.
The ‘Aurora Green’ holds the title of the largest ever Fancy Vivid Green diamond weighing 5.03 carat. Its size is not the only remarkable property of this diamond is that it also has VS2 clarity and no fluorescence which is extremely rare for such a diamond. It was auctioned by Christie’s Hong Kong on May 31st 2016 and sold for a very impressive $16.8 Million which makes the price per carat in excess of $3.3 million dollars! This broke the record set at auction by ‘The Ocean Dream’ that sold in 2014 for $8.6 million, equivalent to $1.5 million per carat.
As mentioned before another famous natural green diamond is ‘The Chopard Chameleon’ which was acquired in 2007 by Swiss jeweller Chopard. He revealed this stunning green diamond to the world in its delicate setting at Baselworld in 2008. It is the centre piece of a ring surrounded by a delicate pavé setting of tiny fancy coloured diamonds and was designed by the renowned jeweller Caroline Gruosi-Scheufele. The Chopard Chameleon is the largest known chameleon diamond in the world, comfortably exceeding the previous record holder in size, a 22.28 carat chameleon heart shaped diamond. It was estimated to be worth $10 Million in 2008.
Famous celebrities who wear natural green diamonds
As green diamonds are so rare, they are not many who have been lucky enough to own/wear these amazing gemstones apart from royalty and the favoured few.
The ‘Orlov Diamond’ is a bluish-green diamond which belonged to Catherine the Great of Russia and is set upon her Imperial Sceptre. There are a total of 180 facets on the diamond which features a rose-style cut and this diamond is said to have the proportions of half a chicken’s egg
Queen Elizabeth is the lucky owner of a very rare chameleon diamond which was bought for Buckingham Palace anonymously. It is a very impressive 3 carat in weight and is heart shaped.
In 2010 and in 2011, Gossip Girl’s Blake Lively was seen wearing a stunning green diamond ring which was designed by Lorraine Schwartz and consists of exquisite deep green coloured diamonds.