Diamond is famously known as the hardest mineral on Earth. But researchers have been pursuing an unusual variant of it — known as hexagonal diamond — that might be even harder. After decades of claims ...

A Chinese research team has produced bulk hexagonal diamond, a crystal structure long theorized to be harder than conventional cubic diamond, from compressed graphite. The work, led by Sun Jian at ...

After decades of debate, researchers say that they have found the clearest evidence yet for this rare form of carbon. Diamond is famously known as the hardest mineral on Earth. But researchers have ...