Japanese electronics manufacturer Kyocera has released a video showing off just how strong its sapphire glass screens really are – smashing rock.

The sapphire glass cover is included in a test against a standard screen. When dropped on a small rock the standard screen cracks up. The sapphire glass screen not only stays mark-free but it actually breaks up the rock into pieces. It also means it's virtually impossible to scratch, even with sharp metal.

Sapphire glass is rated as three times stronger than current Gorilla Glass. That's because sapphire is the second strongest thing on the planet after diamonds.

Apple's iPhone 6 is expected to come sporting a sapphire glass screen. So it looks like the days of seeing cracked iPhones everywhere you look may be coming to a close at last. How that will affect the price of it and other phones with this super screen isn’t yet clear.

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