Weird. JerryRigEverything showed that the cover glass is actually plastic. It's got way too low scratch resistance to be glass. And plastic shouldn't crack like this.
Ah I see. But I wonder why they went for this. Why put the most scratch-sensitive material right on the outside? This way you get all the negative sides of glass (high weight, cracking under pressue or impact) while you get none of the benefits (scratch-resistance).
And in this case the side of the material that's exposed to the user is plastic. Why would Apple brag about it being glass if the user can't even notice it? :)