Strange hexagonal diamonds found in meteorite from another planet

Diamonds present in 4 meteorites in north-west Africa in all probability got here from an historic dwarf planet, and they’re anticipated to be tougher than Earth diamonds

By Alice Klein

Mysterious hexagonal diamonds that don’t happen naturally on Earth have been found in 4 meteorites in north-west Africa.

“It’s actually thrilling as a result of there have been some individuals within the discipline who doubted whether or not this materials even existed,” says Alan Salek at RMIT College in Melbourne, Australia, who was a part of the group that discovered them.

Hexagonal diamonds, like common diamonds, are product of carbon, however their atoms are organized in a hexagonal construction slightly than a cubic one.

Also called lonsdaleite, hexagonal diamonds have been first reported in meteorites within the US and India within the Nineteen Sixties. Nevertheless, the beforehand found crystals have been so small – solely nanometres in measurement – that it was onerous to substantiate whether or not they have been actually hexagonal diamonds.

To hunt for bigger crystals, Salek and his colleagues used a robust electron microscope to look into 18 meteorite samples. One was from Australia and the remaining have been from north-west Africa.

They discovered hexagonal diamonds in 4 of the African meteorites, with some crystals measuring as much as a micrometre in measurement – about 1000 instances larger than earlier discoveries. This allowed the group to substantiate the weird hexagonal construction.

“It’s an vital discovery as a result of now now we have bigger crystals, we are able to get a greater thought of how they fashioned and possibly replicate that course of within the lab,” says Salek.

Based mostly on the chemical composition of the meteorites that introduced them to Earth, the hexagonal diamonds seem to have fashioned inside dwarf planets, says Andy Tomkins at Monash College in Melbourne, who led the analysis.

The group’s evaluation suggests the crystals have been created by a response between graphite – which is product of carbon atoms layered in sheets – and a supercritical fluid of hydrogen, methane, oxygen and sulphur chemical compounds that in all probability fashioned when an asteroid crashed into the dwarf planet and broke it into fragments that ultimately fell onto Earth.

“When the planet broke aside, it was like taking a lid off a Coke bottle – it launched the stress and that drop in stress mixed with excessive temperatures led to the discharge of this supercritical fluid,” says Tomkins.

That is much like the method by which common diamonds are made in labs, by heating graphite with gases like hydrogen and methane, suggesting that a couple of tweaks might produce lonsdaleite as a substitute, says Salek.

Hexagonal diamonds are predicted to be about 60 per cent tougher than common diamonds primarily based on their construction, and this further hardness might have vital industrial functions in the event that they might be made synthetically. For instance, they might probably be used to make ultra-hard noticed blades or different machine elements, says Salek.

Journal reference: Proceedings of the Nationwide Academy of Sciences, DOI: 10.1073/pnas.2208814119

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