Scientists have solved a decades-long puzzle and unveiled a near unbreakable substance that could rival diamond as the hardest material on Earth. The research is published in the journal Advanced Materials.

Scientists have solved a decades-long puzzle and unveiled a near unbreakable substance that could rival diamond as the hardest material on Earth.

Researchers found that when carbon and nitrogen precursors were subjected to extreme heat and pressure, the resulting materials—known as carbon nitrides—were tougher than cubic boron nitride, the second hardest material after diamond.