Chinese Scientists Synthesize Hexagonal Diamond, Potentially Harder Than Natural Diamond

Researchers at Jilin University in China have successfully synthesized hexagonal diamond, a form of carbon that may surpass natural diamond in hardness. This achievement marks a significant advancement in materials science.

Hexagonal diamond, also known as lonsdaleite, was first identified in meteorites in 1967. Unlike the cubic structure of natural diamonds, hexagonal diamonds have a different atomic arrangement, which has been theorized to result in superior hardness. Previous attempts to synthesize this material in the laboratory have yielded only microscopic samples, limiting the ability to study its properties.

The team at Jilin University employed a novel method involving the compression of highly ordered graphite under extreme pressures of approximately 20 gigapascals and temperatures between 1,300 and 1,900 degrees Celsius. This process produced millimeter-sized crystals of hexagonal diamond, large enough for detailed analysis. Structural measurements confirmed the hexagonal arrangement, and mechanical testing suggested that the material may exceed conventional diamond in both stiffness and hardness.

These findings have potential implications for various industries that rely on ultra-hard materials, such as cutting and drilling tools, abrasive coatings, and thermal management systems in advanced electronics. The enhanced properties of hexagonal diamond could lead to equipment with longer lifespans and the development of new high-performance technologies.

Beyond industrial applications, this research provides insights into the processes occurring during planetary collisions. Hexagonal diamond has been identified in meteorites believed to originate from the interiors of shattered dwarf planets. Understanding how this material forms could help scientists better interpret the extreme pressures and temperatures produced during early solar system impacts.

While the synthesized crystals remain a laboratory achievement at this stage, the successful production of measurable quantities of hexagonal diamond opens a pathway for further study and potential future applications of this long-theorized form of carbon.