Chinese Scientists Synthesize World's Hardest Hexagonal Diamond

The breakthrough material, created from compressed graphite, surpasses natural diamonds in hardness and thermal stability, opening new industrial possibilities.

Researchers from Jilin and Sun Yat-sen Universities in China have successfully synthesized a nearly pure hexagonal diamond, also known as lonsdaleite, in the lab.
The synthetic hexagonal diamond exhibits a hardness of 155 gigapascals, significantly surpassing natural diamonds, which typically measure between 70 and 100 GPa.
This new material also demonstrates exceptional thermal stability, withstanding temperatures up to 1,100°C, compared to natural diamonds' limit of around 700°C.
The team achieved the breakthrough by heating highly compressed graphite under specific temperature gradients, yielding millimeter-sized, highly structured blocks of hexagonal diamond.
Potential applications include industrial cutting tools, advanced coatings, and next-generation semiconductors, with further research needed for commercial scalability.