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Tougher than armour, hard as diamond: China’s unbreakable crystal breakthrough
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Zhang Tongin BeijingPublished: 12:00pm, 11 Aug 2026
Chinese scientists have created a diamond with no Achilles’ heel – one that cannot be broken, even by a hard knock with a hammer – according to a paper published in the peer-reviewed journal Nature Synthesis.
While a diamond is the hardest natural material on Earth, it has a major weakness. It is brittle, like glass, and a sharp blow can shatter it. For years, scientists have tried to make diamonds tougher without losing their legendary hardness.
Typically, increasing one characteristic has meant sacrificing the other – seen as a reasonable trade-off for most applications, which include industrial uses such as in cutting and polishing tools.
The team – from the Institute of Physics at the Chinese Academy of Sciences and Beihang University – found a way around this limitation, building an internal support structure to boost a diamond’s toughness by six times while leaving its hardness unchanged.
The breakthrough material is even tougher than the tungsten alloys used in armour-piercing ammunition, according to the paper, which was published online on July 9.
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The secret lies in multi-walled carbon nanotubes (MWCNT) – ultra-strong carbon fibre “cords” that are incredibly thin, about one 10,000th of the width of a human hair, yet dozens of times stronger than steel, the paper said.
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