I'm expecting genuine diamond iPhone and Watch "glass" within a few years.
They could even create the equivalent of a "perfect pixel" guarantee - "perfect lattice" guarantee, the diamond screen is flawless down to the atom or your money back.
That could flip the script on DeBeers in a big way.
[1] https://www.technologyreview.com/s/532636/why-apple-failed-t...
The predecessor to your phone, my Nexus 5, also contains Gorilla Glass 3, and yeah, I don't use a case, I don't use a screen protector, and there are no real scratches on the screen, and it has rode around in my pocket for over 2 years.
Now, that doesn't necessarily mean that a diamond screen would be worse than what exists today but it wouldn't be something invulnerable and resistant to any impact either.