The world’s largest Fancy Black Natural Colour diamond is currently on show at the Sotheby’s premises in the Dubai International Financial Centre. The rare Enigma diamond weighs 555.55 carats and has 55 facets. “Carbonado black diamonds are exceptionally old,” Sophie Stevens, jewellery specialist at Sotheby’s Dubai, tells <i>The National</i>. “We date them to approximately 2.6 to 3.8 billion years old and we believe they have extraterrestrial origins. “White diamonds and other coloured diamonds are typically found in Kimberlite rock and they come up to the surface of the Earth through volcanic eruption. Whereas Carbonado black diamonds are found in sedimentary alluvial deposits, which means they are carried down by water, such as streams. They are found very near to, if not on, the Earth’s surface." Carbonado diamonds are only known to exist in Brazil and the Central African Republic, which lends credit to the theory that they are the result of a meteorite making impact with the Earth billions of years ago, when the two continents were connected to form the supercontinent Rodinia. “What we think either happened is an asteroid collided with the Earth and created chemical vapour deposition that formed these diamonds, or indeed that these diamonds were part of the meteorite as it collided with the Earth,” Stevens explains. Previously unseen on the market, Enigma was unveiled in Dubai on Monday and will be on view in the emirate until Thursday, before it travels to Los Angeles and then London, where it will go on sale in a single-lot online auction between February 3 and 9. There is no reserve price for the auction. “Because black diamonds haven’t been seen on the market frequently, there are very few past examples at auction. So it’s a good idea to let the market decide and it will be interesting to see what the current demand is. One of the last ones at auction was in 2001 and it was a much smaller stone at 33 carats, while this one is 555.55,” says Stevens. “We chose Dubai and LA because of the nature and the type of diamond. We think it has a wider appeal to different collectors, not just your traditional gemstone collectors. So we thought Dubai and LA would be perfect to appeal to that wider database.” Enigma was acquired as a rough stone in the 1990s by its current owner, who proceeded to have it cut into its current shape, which is inspired by the Hamsa, a sign of power, protection and strength. “What is also exceptional about these black diamonds is they do not have the same chemical make-up as white diamonds, which have a single line of crystal symmetry, making them much easier to cut and facet. These are what we call polycrystalline, so they are made up of many aggregated small diamond crystals. The technical skill required to cut this in the first place, let alone to that very specific weight of 555.55 and with the 55 facets, is just remarkable,” says Stevens. Sotheby’s is accepting cryptocurrency, in addition to normal currency, for this sale. “We are not accepting crypto on everything. But for very select, unique stones, we are. We did this last year in Hong Kong, with the Key diamond, a D flawless pear-shaped diamond weighing 101.38 carats and it was paid for in cryptocurrency. “With the Enigma, because we are trying to appeal to beyond the traditional jewellery buyer, maybe these are people involved in the crypto world, or people involved in crypto start-ups. It makes it a bit more appealing to them. We have to adapt with the times, so we are exploring this across the business.”