The gemstone lost its title of the “world's hardest material” to man-made nanomaterials some time ago. Now a rare natural substance looks likely to leave them all far behind – at 58 per cent harder than diamond.
The gemstone lost its title of the “world's hardest material” to man-made nanomaterials some time ago. Now a rare natural substance looks likely to leave them all far behind – at 58 per cent harder than diamond.