In a major scientific milestone, Chinese researchers have successfully synthesised a rare form of diamond found naturally only in meteorites, the hexagonal diamond, marking a leap forward in the quest for superhard materials, according to the Chinese media reports.
The study, published Wednesday in Nature, details how scientists from the Centre for High-Pressure Science & Technology Advanced Research transformed graphite into a high-purity hexagonal diamond under precisely controlled high-temperature, high-pressure, and quasi-hydrostatic conditions. This crystal structure is believed to be harder than conventional Earth diamonds, which, despite their famed strength, have weaknesses due to slippage along certain planes.
Hexagonal diamonds, or lonsdaleites, boast a more robust atomic arrangement, but previous attempts to create them in laboratories often resulted in ordinary cubic diamonds. The breakthrough came from using high-purity natural graphite single crystals and in-situ X-ray monitoring to track structural changes during synthesis.
Lead researcher Yang Liuxiang said the approach overcame long-standing challenges in diamond creation, setting a methodological foundation for future material innovation. Ho-kwang Mao, a renowned high-pressure science expert and foreign member of the Chinese Academy of Sciences, called the achievement a "new pathway" for developing next-generation superhard materials and advanced electronic devices.
"Firstly, selecting ultra-pure, impurity-free natural graphite single crystals as raw material facilitated the creation of highly ordered, micrometre-sized hexagonal diamond samples," he told the South China Morning Post.
"Secondly, they used live monitoring - gradually compressing graphite crystals while watching structural changes with real-time X-ray imaging. This prevented defects and produced pure, perfectly formed hexagonal diamond blocks."
The laboratory-grown hexagonal diamond, at a hundred-micron scale, could redefine industrial applications requiring extreme durability, potentially outperforming traditional diamonds in both mechanical and electronic uses.
