That $10,000 Android we looked at a couple weeks back, the Vertu Ti, might not have been the most impressive phone in the specs department, but it did have one killer feature: a screen made of synthetic sapphire. Single crystals of aluminum oxide like this have a Mohs scale hardness of nine, meaning you're going to need something in the same league of hardness as other sapphires or diamonds in order to scratch them. At the MWC this year, we got to check out a demonstration of just what kind of damage sapphire screens can endure.
In the battle of glass versus concrete, concrete will almost certainly prevail, but when paired up against a sapphire screen, the rock is unable to make a scratch. The same test with Gorilla Glass 2 quickly results in a marred screen.
Of course, price means we won't see sapphire replace Gorilla Glass anytime soon, but who knows; if this gets cheaper to fabricate, it might just be feasible to take it mainstream several more years down the line.