A heavy black diamond named ‘The Enigma‘ is set to be sold at an auction at Sotheby’s, an art and jewels company headquartered in New York City. 

The gem, also known as carbonado diamond, weighs a whopping 555.55 carats. While carbonados have only been found in Brazil and the Central African Republic, many researchers and scholars theorize The Enigma’s origin to be from  outer space.

According to Sotheby’s, the enigmatic diamond will be auctioned from February 3 at 6 am PST to February 9. Cryptocurrency will also be accepted as payment.

The firm also added that The Enigma tops the list as the largest faceted fancy black diamond to ever be auctioned and has previously been listed in the 2006 Guinness Book of World Records as the world’s largest cut diamond.

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In conversation with Reuters, Aaron Celestian, a geologist and the custodian of mineral sciences at the Natural History Museum of Los Angeles, said, “They are shrouded in mystery as to the origin or formation because there’s not that many of them found on Earth.”  

Celestian further added that most carbonados date back 2.6- 3.2 billion years. According to him, Earth being 4.6 billion years old, carbonados came into existence during the movement of tectonic plates and the beginning of the atmosphere’s oxygenation.

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Elucidating the origin, Celestian stated, “We think that they could have formed super deep within the Earth’s interior, far deeper than what we already know of diamonds. There’s hypotheses that suggest that they formed at impact sites where a large asteroid hit Earth. There’s also interstellar hypotheses that suggest that they grew in space and then later fell on the surface of Earth.”

The geologist also believes that delving into The Enigma’s origins can help scientists better understand Earth’s minerology and the evolution of the solar system.

The Enigma is speculated to be sold at between $4 million and $7 million. The rare diamond was earlier in possession of its owner for over two decades, but not much is known about its history before being acquired.