How was hexagonal diamond made?

Scientists produce and test lonsdaleite

Researchers in China report the creation of small, pure samples of lonsdaleite — the long-sought hexagonal form of carbon long suspected to be harder than ordinary cubic diamond. The team produced materials that they term pure hexagonal diamond and subjected those samples to material‑property tests that indicate greater hardness than natural diamond.

Why the result is important:

• It confirms the existence of a stable, hexagonally bonded carbon lattice in macroscopic samples rather than only in tiny or impure fragments.
• Hardness measurements position the material as a candidate for extreme‑wear applications where diamond is already used, such as cutting, drilling and abrasives.
• It settles a decades‑long materials puzzle: previous reports of hexagonal diamond were often disputed because samples were mixed-phase or contaminated.

Caveats and next steps

• The reported samples are small, and translating laboratory synthesis into industrial production will require new methods and scale‑up.
• Independent replication and detailed structural characterization will be essential to cement the claim and to map the full suite of mechanical, thermal and optical properties.
• Researchers will also explore synthesis routes that can control grain size, purity and defect populations, because those factors strongly influence performance in real-world components.

If the material’s superior hardness holds up under broader scrutiny, it could spur a wave of engineering development around applications that demand the toughest available materials.