Chinese scientists at Zhengzhou University have synthesized the first bulk pure samples of hexagonal diamond-also known as lonsdaleite-a mineral long theorized to be harder than natural cubic diamond.
Using highly ordered graphite, they applied 20 gigapascals of pressure and temperatures between 1,300°C and 1,900°C for 10 hours. The resulting 1.5-millimeter samples enabled definitive structural and spectroscopic confirmation-ending decades of debate over lonsdaleite’s authenticity.
Hexagonal diamond proved stiffer, harder, and far more oxidation-resistant than cubic diamond-making it promising for high-temperature drilling, quantum sensing, thermal management in electronics, and advanced abrasives.
The discovery validates meteoritic findings-including from Canyon Diablo (Barringer Crater) and Goalpara meteorites-and establishes a scalable synthesis route for industrial use.