Chinese Scientists Create Stronger ‘Hexagonal Diamond’ in Lab

Researchers in China have successfully created what they assert is the first pure sample of hexagonal diamond, a rare variant thought to be stronger than natural diamonds. This breakthrough was announced in a study published on March 4, 2026, in the journal Nature. Hexagonal diamond, also known as lonsdaleite, has intrigued scientists since its theoretical existence was proposed in the 1960s, and its formation in laboratory settings has historically proven challenging.

Natural diamonds, or cubic diamonds, have long been revered as the hardest material on Earth. Their structure consists of carbon atoms arranged in a cubic lattice, which has set the standard on the Mohs hardness scale. In contrast, hexagonal diamonds feature a lattice composed of hexagonal patterns, reminiscent of a honeycomb structure. This unique arrangement may confer enhanced properties, making hexagonal diamond a subject of significant research interest.

The initial concept of hexagonal diamond emerged from the Pittsburg Coal Research Center in 1962, where scientists speculated about the potential for carbon atoms to bond in a hexagonal configuration. By 1967, laboratory experiments successfully identified lonsdaleite, yet doubts lingered over its existence, particularly regarding findings in natural settings like meteorites.

Identifying hexagonal diamond has been complicated by its propensity to exist in mixtures with cubic diamonds and other minerals, complicating its analysis. The latest study addresses this issue by producing pure hexagonal diamond samples measuring approximately 0.06 inches (1.5 millimeters) in diameter. This size is sufficient for accurate material property measurements, offering clarity in understanding its characteristics.

The researchers discovered that hexagonal diamond is both stiffer and harder than its cubic counterpart. Notably, it exhibits greater resistance to oxidation, allowing it to endure higher temperatures without degrading. This quality positions hexagonal diamond as a potentially valuable material in various industrial applications, particularly in drilling and cutting tools, where durability and thermal stability are paramount.

The research team utilized a process involving the compression of highly ordered graphite at 20 gigapascals—approximately 200,000 times the atmospheric pressure at sea level—combined with temperatures ranging from 2,300 to 3,450 degrees Fahrenheit (1,300 to 1,900 degrees Celsius). However, it was noted that at elevated temperatures and pressures, lonsdaleite tends to transform into cubic diamond, presenting a further challenge for scientists.

In addition to its industrial implications, the hexagonal diamond’s presence in meteorites can provide insights into the formation processes of these celestial bodies and enhance our understanding of the solar system’s history. According to Chong-Xin Shan, co-lead of the study and a physicist at Zhengzhou University, the discovery has opened avenues for practical applications in fields such as quantum sensing and thermal management materials.

The study not only confirms hexagonal diamond’s existence but also outlines a viable strategy for producing it in bulk. This advancement could pave the way for further scientific exploration and the development of new tools and technologies that harness the superior properties of hexagonal diamond, extending beyond the limitations of conventional cubic diamond.

As researchers continue to explore the potential of this remarkable material, the implications for both science and industry are vast, promising to unlock new capabilities in technology and materials science.