American Marconi Wireless News - Largest ever cut diamond at auction sells for £3.2 million

The rare black, or carbonado, diamond is believed to have been created when a meteorite or an asteroid hit Earth more than 2.6 billion years ago.

The 555.55 carat, 55-faced diamond reached £3.16 million, excluding the buyer's premium, at an online sale held by London's renowned Sotheby's auction house.

Carbonados are usually found close to the Earth's surface, suggesting extraterrestrial origins.

"It is thought that this specific type of black diamond was created either from meteoric impacts producing natural chemical vapour deposition or an extraterrestrial origin -- from supernovae explosions that formed diamond-bearing asteroids which ultimately collided with the Earth," said the auction house.

One of the most difficult substances to cut, the diamond had never previously been shown by its unnamed owner of the past 20 years.

Experts took three years turning the rough diamond into a 55-face jewel and it recently went on show in Dubai, Los Angeles and London.

Its shape was inspired by the Middle East palm-shaped symbol of power and protection, the Hamsa, which is also associated with the number five.

"The Enigma's price did not quite reach intergalactic levels. But what cannot be denied is that the Enigma is a diamond with unparalleled bragging rights," said Tobias Kormind, managing director of Europe's largest online jeweller, 77 Diamonds.

"The size, shape and source of the Enigma diamond make it ground-breaking and amazing," he added. "Most diamonds are cut into one of 10 popular shapes but the Enigma's form resembles a hand."

The Enigma, which was listed by Guinness World Records in 2006 as largest-known cut diamond in the world, is not a gem quality diamond, and carbonados are not normally used in jewellery or sold at auction, but have grown in popularity recently.

They are usually used in industrial drilling due to their extraordinary hardness.

Sotheby's called the diamond a "cosmic wonder" ahead of the sale, which also accepted cryptocurrency bids.

Last year in Hong Kong, the Key 10138 diamond sold for $12.3 million, which was paid in cryptocurrency.

A.Mahlangu--AMWN