![]() The hot, low-pressure conditions in the aftermath of a massive impact actually mimic a technique we used to grow diamonds in labs today, he says, where hot gases deposit carbon that is turned into diamonds. “If you have the right gas mix, you can start forming diamonds on carbon.” “You have this unusual gas mix that’s everywhere, that’s making reactions happen,” he says. The conditions inside the cloud of rock and gas formed by the impact turned out to be just right for growing diamonds, Tomkins thinks. When it was destroyed by an impact, bits of the mantle were scattered into space, where they quickly cooled.Īs they cooled, gases like hydrogen, carbon monoxide, and hydrogen sulfide that had once dissolved inside the mantle began to leach out. He thinks the ureilites started as partly liquified rock within the super-hot mantle of their parent body. What they did - To learn more about these glitzy asteroids, Tomkins and his team gathered 18 ureilites that landed around the world and examined them with electron microscopy, a technology that helps labs peer at samples with enough detail to detect their chemical composition.īy looking at the carbon inside the ureilites, Tomkins says they were able to piece together a new story for what happened billions of years ago - when the huge asteroid they were once part of met its demise. The pieces of lonsdaleite scientists find are measured in nanometers, or billionths of a meter. Ureilites often contain lonsdaleite, and Tomkins and his coauthors found small bits of the mineral in several of the meteorites they studied.īut lonsdaleite is a bit of a mystery - it’s typically found only in meteorites, and in vanishingly small quantities. Lonsdaleite is even harder than diamond, making it potentially useful for industrial applications here on Earth, but we know very little about it. ![]() The carbon atoms in diamonds are arranged in a cubical shape that repeats over and over again, forming the ultra-hard, super-shiny crystals that adorn fancy engagement rings.īut if those atoms are placed in a hexagonal shape and encounter the right combination of temperature and pressure, they can form what’s known as lonsdaleite, a rare type of carbon that may be even harder than diamond. Here’s the background - Diamonds are essentially a special arrangement of carbon atoms, the same element that comprises much of our bodies. And part of that process involved the creation of a type of carbon even rarer than diamond. Researchers had previously suggested that the shiny gems emerged from the shock of a massive impact, or that they grew deep inside a Mercury-sized planet that once existed in our solar system.īut Tomkins and his co-authors think the diamonds grew in a different way entirely - in a manner that mimics how we create lab-grown diamonds today. What’s new - Tomkins is the co-author of a new paper published in the journal PNAS that sought to explain how these rare meteorites became chock-full of glittery carbon. “And a large proportion of that carbon is diamond.” “Ureilites have three to seven percent carbon in them,” Tomkins says. ![]() One dead giveaway that you’re dealing with a rare ureilite: Diamonds. Meteorites called achondrites form at high temperatures, likely deep within an asteroid. ![]()
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