When it comes to purchasing green precious stones, the majority of people instantly look to the emerald, but not many people are aware that 100% natural green-coloured diamonds are also an option. Find out how green diamonds form, what special features they have, and how valuable they are.
Diamonds are formed over the course of millions of years, deep beneath the earth's surface. Carbon, the building block of all diamonds, is compressed by the high pressure more than 100 kilometres beneath the surface of the earth, and together with heat, this can bring about the formation of a diamond – the hardest material in the world. With a little luck this will later reach the earth's surface via a volcanic vent before the heat destroys it again.
The majority of diamonds are colourless
or have a slightly yellowish shine, which comes about as a result of the incorporation of nitrogen into the precious stone's crystal lattice. Likewise, with many other colours of diamond, different substances
within the structure of the diamond are responsible for the colour. In this respect, green diamonds are the sole exception, as in this case natural nuclear radiation during the formation of the diamond is required to produce the colour. Depending on the strength and duration of the radiation, the intensity of the colour may vary.
To get straight to answering the question that shoots through many people's minds: green diamonds are not radioactive - radiation was indeed responsible for the colouring, however, the stones themselves have long since stopped emitting any alpha, beta, or gamma rays and are completely harmless.
Alongside the very rarely occurring pure green diamonds, many green diamonds have a so-called overtone, a second colour
that blends with the base tone, such as yellow, blue, or brown. The colour spectrum of green diamonds is broad, ranging from brownish and olive tones, to light yellowish green or turquoise. As is standard with coloured diamonds, the cut of the diamonds is based primarily on the colour - on how this can be shown off in its best light. Unusual cuts are therefore more common with "fancy" diamonds than with their colourless brothers and sisters.
The most famous green diamond is the "Dresden Green", an almost 41-carat green diamond from India. It is named after the German city, the seat of the Saxon elector August III, also known as August the Strong. He purchased the diamond in the early 1740s. The stone only narrowly avoided the art theft of November 2019, when many valuable, historical pieces were stolen from the Green Vault in Dresden. Luckily, at this point in time it was being exhibited in New York.
Also very well-known is the "Ocean Dream", a bright, blue-green diamond, which was auctioned off in 2014 by Christies in Geneva, as part of the legendary "Magnificent Jewels" auctions. The 5.5-carat precious stone achieved an outstanding result of almost 8 million Swiss Francs, which at the rate of exchange at the time amounts to just over 7 million euros.
The majority of green diamonds are rather small, with examples weighing more than 1 carat very rare. The price for stones with a weight of one carat starts at around €45,000 for stones with a slightly greenish colour, whereas stones with a "fancy vivid green" colour can fetch €250,000 per carat without any difficulty. Unusual green diamonds, which are popular amongst collectors, can achieve even higher values.
In conclusion: unlike affordable green emeralds, green diamonds are only suitable for investors with considerable wealth.
As rare as natural green diamonds are, relative to the increase in value it is actually very simple to add a green colour to colourless diamonds after they have formed. To this end, the diamond is actually inserted into radioactive radium salt , whereby the constant, relatively low level radiation colours the diamond green over time.
While recent processing of this nature can be proven using a Geiger counter, proving manipulation that took place some time ago is more difficult.
In order to make it easier for laboratories such as the GIA to recognise natural green diamonds, the diamond cutter will generally leave a small, inconspicuous area on the girdle of the diamond, the rondiste, unfinished.
Investment diamonds should only ever be purchased with a certificate from a reputable laboratory, and in the case of green diamonds this is all the more important in order to be able to safely rule out the possibility that the colour of the diamond has been altered.
Are you interested in purchasing 100% natural, coloured diamonds as an investment? The experts at BNT Diamonds will be happy to advise you. Contact us by email of chat, or speak to our team directly by calling +32 3 201 24 90.
