Meet the Mysterious Space Diamond

By Madeline Holcombe, CNN

Scientists have debated its existence. Tiny traces provided clues. Now researchers have confirmed the existence of a celestial diamond after finding it on Earth’s surface.

The stone, called lonsdaleite, has a higher hardness and strength than a regular diamond. The rare mineral arrived here via a meteorite, according to new research.

Additionally, the natural chemical process by which scientists believe lonsdaleite was formed could inspire a way to make ultra-durable industrial components, according to the authors of the study published Sept. 12 in the journal Proceedings of the National Academy of Sciences.

The revelation began to unfold when geologist Andy Tomkins, a professor at Monash University in Australia, was in the field categorizing meteorites. He came across a strange type of “folded” diamond in a space rock in northwest Africa, said study co-author Alan Salek, a doctoral student and researcher at RMIT University in Australia.

Tomkins speculated that the meteorite that contained the lonsdaleite came from the mantle of a dwarf planet that had been around for about 4.5 billion years, Salek said.

“The dwarf planet was then catastrophically hit by an asteroid, releasing pressure and leading to the formation of these really weird diamonds,” he added.

With its cutting-edge methods and possibilities for the future, the discovery is exciting, said Paul Asimow, professor of geology and geochemistry at the California Institute of Technology. Asimow did not participate in the study.

“It really takes advantage of a number of recent developments in microscopy to do what they did as well as they did,” Asimow said.

The team was able to analyze the meteorite using electron microscopy and advanced synchrotron techniques, which constructed maps of the space object’s components, including lonsdaleite, diamond and graphite, according to the study. .

Diamonds and lonsdaleite can form in three ways. This may be due to high pressure and temperature over a long period of time, which is how diamonds form on the Earth’s surface; the shock of a hypervelocity meteor collision; or the release of broken graphite vapors that would attach to a small diamond fragment and collect on it, Asimow said.

The method that creates the mineral can influence its size, he added. The researchers proposed in this study that the third method formed the largest sample they had found.

“So nature has provided us with a process to try to replicate in industry,” Tomkins said in a press release. “We believe lonsdaleite could be used to make tiny, ultra-hard machine parts if we can develop an industrial process that promotes the replacement of preformed graphite parts with lonsdaleite.”

What is it exactly?

Long before this discovery, scientists debated the existence of lonsdaleite, Asimow said.

“It seems like a strange claim that we have a name for a thing, and we all agree what it is,” he added, “and yet there are claims in the community according to which it’s not a real mineral, it’s not a real crystal, that you could have a macroscopic scale.

Scientists first identified pieces of the mineral in 1967, but they were tiny – around 1 to 2 nanometers, which is 1,000 times smaller than what was found in the most recent discovery, said Salek.

The discovery of a larger sample showed that lonsdaleite is not just an anomaly compared to other diamonds, Asimow said.

Ordinary diamonds, such as those you see in fine jewelry, are made from carbon and have a cubic atomic structure, Salek said. As the hardest material known to date, they are also used in manufacturing.

Lonsdaleite is also made of carbon, but instead has an unusual hexagonal structure, he added.

Researchers have previously offered models for the structure of lonsdaleite, and they speculated that the hexagonal structure could make it up to 58% harder than regular diamonds, Salek said. This hardness could make rare space diamond a valuable resource for industrial applications if scientists can find a way to use the new production method to create large enough minerals.

What does this mean for us?

Now that scientists know about this mineral, the discovery raises the question of whether they can replicate it.

Tools such as saw blades, drill bits and mine sites need to be durably hard and wear-resistant, so a ready supply of lonsdaleite could make them even better, Salek said. And now, with a credible scientific theory of how these larger deposits formed, a rough plan exists to make lonsdaleite in the lab.

From this discovery, we can also learn more about the interactions of the universe, said Phil Sutton, senior lecturer in astrophysics at the University of Lincoln in the UK. Sutton did not participate in the research.

In uncovering the history of where we came from and how we evolved, he added, it’s important to know that materials were exchanged between environments, even across solar systems.

Scientists named lonsdaleite after crystallographer Dame Kathleen Lonsdale, who in 1945 became one of the first women elected to membership in the Royal Society of London.

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