This Huge Black Diamond Just Sold For $4.3 Million. No One Knows Where It Came From

ByMaya Wei-HaasPublished February 9, 2022• 8 min readWith a final closing bid of $4.28 million, an anonymous buyer just became the new owner of the 555.55-carat black diamond known as the Enigma. The sale of this bizarre stone has reignited a long-simmering debate about where it came from, stoked by the controversial theory that it…

Printed February 9, 2022

8 min learn

With a final closing relate of $4.28 million, an anonymous buyer merely turned the fresh proprietor of the 555.55-carat sunless diamond is named the Enigma. The sale of this peculiar stone has reignited a lengthy-simmering debate regarding the build aside it came from, stoked by the controversial concept that it might presumably be pleased arrived from outer deliver.

The Enigma and all varied carbonado diamonds fashioned in a mysterious match some 3.8 to 2.6 billion years ago. Jet sunless, opaque, and whole of viewed holes, carbonados be pleased a varied mixture of physical and chemical system unlike any varied known diamonds.

They are chanced on in biggest two regions of the realm—Brazil and the Central African Republic—and can develop astonishingly massive. The group involves the hulking 3,167-carat Brazilian carbonado is named Sergio—the biggest diamond ever chanced on. And the Enigma itself isn’t any diminutive rock at nearly the dimension of a racquetball. “Right here’s a refined honking immense diamond,” says Thomas Stachel, a mineralogist specializing in diamonds at the College of Alberta.

Unless lately, though, carbonados were acknowledged not for their beauty nevertheless for their toughness. Now not like the one crystals of broken-down gem diamonds, carbonados are made up of an interlocking community of crystals, which imparts additional resistance to fracturing below stress and makes them treasured as industrial abrasives. Carbonados were weak as drill bits that can puncture tricky rock and with grinding wheels that sharpen instruments.

Carbonado’s many oddities be pleased led to a slew of theories about their starting build aside. “There will not be any single mannequin that explains all the pieces,” says Wuyi Wang, vice president of compare and style at the Gemological Institute of The US, who licensed the Enigma as a pure carbonado.

Burnt diamonds

The fable of these extremely-tricky minerals unfolds in two spots on either aspect of the Atlantic Ocean. Gloomy diamonds were chanced on in the 1840s by miners in eastern Brazil who named the minerals carbonado after the Portuguese observe for burnt or carbonized. A protracted time later, carbonados also turned up in the Central African Republic—the biggest varied build aside of living they’ve ever been chanced on.

The carbonados at these two places “are so equivalent in minute essential points” that they be pleased got to be connected, says Peter Heaney, a mineralogist at Pennsylvania Express College. Carbonados were in all likelihood deposited when the 2 landmasses were joined as a single swath for greater than one billion years, splitting into the paired places after Earth’s final supercontinent Pangea broke aside starting 180 million years ago.

Thru the millennia, wind and water be pleased erased most varied clues to the sunless diamonds’ origins, eroding the rocks that the gems fashioned in and scattering the grains along the shores of primitive rivers.

Spherical 150 years ago, a equivalent field shrouded the origins of the kind of diamond that is most ceaselessly mined this present day, says Pierre Cartigny, a geochemist who specializes in diamonds at the Paris Globe Institute of Physics. Answers began to consume shape in the 1870s when the diamonds were chanced on embedded in vertical pipes of volcanic rock in the Kimberley deliver of South Africa. As scientists later realized, violent volcanic eruptions blasted these conduits to the skin, dragging the stones now is named kimberlite diamonds from deep underground with a surge of magma.

For the carbonados, Cartigny says, “we’re most ceaselessly support 150 years ago.” With out a host rock, scientists can biggest uncover about clues in the uncommon system of the sunless diamonds themselves—nevertheless each one appears to be like to relate a varied fable.

Befitting its title, no one is conscious of exactly the build aside on Earth the Enigma comes from. The diamond used to be estimated to be greater than 800 carats, such as 160 grams, when it used to be bought anonymously in the 1990s, primarily primarily based fully on the vendor’s consultant. It used to be later cut into its distinctive 55-aspect shape—a job that took three years as a result of the stone’s unprecedented toughness.

By meteorite or mantle

As diamonds crystallize in the large pressures deep inside of Earth, they every so often encapsulate minerals from the planet’s mantle, such as deep crimson garnet or inexperienced olivine. But these minerals are absent in carbonados. As a replacement, geologists be pleased chanced on an exotic array of metals, such as the titanium nitride mineral osbornite, which is most ceaselessly chanced on in meteorites.

Maybe the diamonds fashioned on carbon-well off stars or planets, bits of which were carried to Earth in meteorites for the interval of a interval between 4 and 3.8 billion years ago when deliver rocks step by step pelted our planet.

Stephen Haggerty, a diamond geophysicist at Florida Worldwide College, in the beginning proposed this extraterrestrial starting build aside at the 1996 conference of the American Geophysical Union—and he serene vehemently contends that is the biggest logical explanation for the carbonado’s many curiosities.

“I’d be fully overjoyed if anyone comes up with a scientifically sturdy various,” he says.

Other scientists aren’t so obvious. When Penn Express’s Heaney first began finding out carbonados in the 1990s, the meteorite proposal regarded a logical explanation. But the more sunless diamonds he analyzed, the more likely it perceived to him that they fashioned in Earth’s mantle.

He points out that scientists be pleased identified about a of the same exotic metals in kimberlite diamonds. And osbornite, while rare, has also been chanced on encapsulated in minerals and rocks fashioned deep in Earth’s mantle.

But the proof that in actual fact changed Heaney’s mind used to be the mammoth dimension of many carbonados. Diamonds were chanced on in meteorites—or fashioned by the crude warmth and stress of meteorite impacts—nevertheless these extraterrestrial stones are all diminutive.

“It be nothing like a jewel,” Cartigny says. “You might presumably presumably not make anything else of it.”

The explicit stipulations in the mantle that might enable for carbonado formation live unsure. One puzzling feature is that all carbonados are stuffed with holes, like sponges. Most Earth diamonds impress not not up to a hundred miles below the skin in sizzling temperatures and crushing pressures. Pores couldn’t continue to exist such stipulations.

“They would per chance merely crumple on themselves,” Haggarty says, noting as a replacement that such pores might presumably be pleased fashioned as molten carbon degassed on the skin of death stars.

Other compare suggests the pores stands out as the terminate result of carbonados crystallizing from sizzling subterranean fluids, or in all likelihood the cavities were as soon as stuffed with minerals which be pleased lengthy since washed away. Heaney suggests the cavities might presumably be pleased as soon as contained phosphate minerals enriched in radioactive points, which might presumably be pleased broken the diamonds’ crystal lattice construction and darkened the diamonds’ colour as they decayed.

The interconnected networks of pores, nevertheless, make it complicated to notice any final cloth, because it’s not straightforward to relate whether or not inclusions are authentic or minerals that fashioned later in the diamond’s life, Cartigny says.

“The carbonado in actual fact is a complicated field,” Stachel says, adding that the main might presumably lie in the chemistry of the diamonds themselves.

Chemical curiosities

While diamonds are fully aloof of carbon, the aspect can consume the impress of heavy or gentle isotopes. Upright to their nature as enigmas, carbonados’ isotope signature differs from most frequent diamonds: It be great lighter than diamonds that impress deep inside of Earth, more such as the natural carbon that makes up life.

Some scientists counsel that this gentle carbon signature might presumably indicate carbonados fashioned from natural cloth dragged deep below the skin in subduction zones, a mechanism previously proposed for the formation of some frequent diamonds. Some three billion years ago, when carbonados were forming, life would be pleased merely began to consume shape.

“Are carbonados fossils of the very earliest organisms to impress on Earth?” Heaney wonders. “No person is conscious of the acknowledge to that.”

But Cartigny and his colleagues chanced on a clue that hints at one other provide. In 2010 the researchers chanced on diamonds with a strikingly equivalent chemistry to carbonados in French Guyana. The diamonds were embedded in komatiite—a impress of volcanic rock from excessively sizzling and liquidy lavas that biggest flowed early in Earth’s historical previous. While these diamonds’ construction differed from carbonados’ mashup of a whole lot of crystals, Cartigny means that the searing warmth of the komatiite lavas might presumably spur the crystals to consume on carbonado-like kinds.

“We are able to not reject anymore that carbonado can impress from the Earth’s mantle,” Cartigny says.

A definitive acknowledge, nevertheless, might presumably biggest reach from finding more of these sunless diamonds. Maybe one will more than likely be pleased an inclusion of cloth that points to an unambiguous provide, or this might be embedded in a host rock that displays its accurate origins.

Within the meanwhile, the Enigma stands as a shimmering and primitive reminder of the a massive preference of wonders and mysteries our universe serene holds.