Ultra-hard material to rival diamond discover
<p>Scientists have solved a decades-long puzzle and unveiled a near unbreakable substance that could rival diamond, as the hardest material on earth, a study says.</p> <p>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.</p>