An unknown buyer used $4.3 million in cryptocurrency to buy a billion-year-old space diamond from Sotheby's

• Sotheby's sold a billion-year-old black diamond from space for $4.3 million worth of cryptocurrency.
• Named the Enigma, the diamond is 555.55 carats with 55 facets, aka flat surfaces.

A billion-year-old diamond from space sold at auction for $4.3 million worth of cryptocurrency.

Sotheby's announced Wednesday that the Enigma — an extremely rare, black 555.55-carat diamond — sold to an unidentified buyer who paid in cryptocurrency. The Enigma, according to the Guinness World Record Book, is the largest cut diamond in the world.

While most diamonds are uncovered deep within the Earth, the Enigma is an "extremely rare carbonado," which is a type of diamond discovered near the Earth's surface and believed to have extraterrestrial origins, the London-based auction house said.

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

On Twitter, crypto entrepreneur Richard Heart made a video claiming he was the buyer of the rare space diamond. He said once the payment goes through, he'll rename the item the HEX.com diamond, a reference to a crypto platform he's part of.

In its rough original form, the diamond weighed more than 800 carats. It took three years to get it into its current form with 55 facets, aka flat surfaces, weighing exactly 555.55-carats and having a high degree of polish, Sotheby's said. The Enigma's chosen shape is a Hamsa, a Middle Eastern palm symbol representing protection, blessings, power, and strength.

The nearly 300-year-old auction house has been diving into the crypto world. Last year, it began accepting cryptocurrencies as a form of payment in an effort to expand its client base and has been auctioning digital collectibles known as NFTs.

Crypto enthusiasts have a propensity for big items. The Wall Street Journal in its report said the auction house sold a 100-carat diamond for $12.3 million in crypto in July. Also last year, crypto Twitter rallied around tiny cubes of Tungsten that are extremely dense. They even bid for the opportunity to touch a 2,000-pound Tungsten cube once a year.