When the iPhone 4's screen was shattered, people said that the test wasn't valid. Only scratch-resistant. But it seems that "30 times harder than plastic" can still be scratched in normal use.
In his review, Walter Mossberg agreed. He said that he tried to break it and scratch it, and he couldn't do it:
I dropped it several times from a few feet onto a hard surface with no problem, and it acquired no scratches at all in my testing, even though I didn't use a case or coddle it.
But as this photo shows, he really didn't try hard enough.
Gdgt editor Ryan Block didn't even try to scratch his, but he got a scratch anyway in normal daily use: Gdgt editor Ryan Block takes this photo of Engadget's J. Topolsky's official Apple review iPhone (thanks metronome49):
Just spotted on the iPhone 4's supposedly nigh-indestructible glass: scratches. Seriously. Not good!
Of course, Apple's own claim was not to be scratch-proof, but scratch-resistant.
In their advertising, Apple says that the iPhone 4's aerospace-grade glass is "Chemically strengthened to be 20 times stiffer and 30 times harder than plastic". According to them, "the glass is ultradurable and more scratch resistant than ever." But, they said it's 30 times harder than plastic, not 30 times more scratch-resistant than plastic, meaning that "more scratch resistant" might mean just 1 or 2 times more so than plastic, and less of an improvement over glass. Who knows.
The bottom line is, even if the iPhone 4 is more scratch resistant than the previous iPhone that doesn't mean you should be throwing it around, or putting it in the same pocket as your keys—it can still scratch. Even on day one. [Twitter]