reputation is easy to keep if consumers know nothing about the science behind mohs scale hardness.
Well I've certainly never been under the impression that screens or SP's were scratchproof!
Here's a little information I found in pursuit of my own ongoing self-education - perhaps you can provide more insight:
Gorilla Glass (original)
Vickers Hardness (200g load)
Un-strengthened 622 kgf/mm?
Strengthened 701 kgf/mm?
Gorilla Glass 3
Vickers Hardness (200g load)
Un-strengthened 534 kgf/mm?
Strengthened 649 kgf/mm?
Evidently there are different methodologies by which 'hardness' can be calculated, as it is possible for two items with a higher hardness rating on Moh's scale to be rated in opposite relative hardness on Vickers scale (
source). As best I can tell, the Vickers scale demonstrates resistance to fracture (note that GG3 is less resistant than original GG); I'm not knowledgeable enough to review those white papers to determin which data (if any) might lead to a Moh's scale rating to gauge actual scratch resistance. Given that (from general web search) most steels are harder than 5 on Mohs scale, it seems safe to say that GG3 would merit at least a higher rating than that, since steel knives to do not leave scratches.
General searches report tempered glass to typically range from 6-7 on Moh's scale, so it doesn't seem to be too hard a leap to expect Corning to have reached / extended beyond the upper end of that estimate.