To begin with I was interested in answering the question “Why did my tempered glass phone screen protector scratch easier than my phone screen?” (as you might be able to tell, I got just a little off topic, nonetheless I can use some of the knowledge from previous slides and a few more sources to tie the general science of glass to my original question).
I have a google pixel 2 XL. Released in 2017 the screen is made of gorilla glass 5, which is a couple generations behind their most recent innovation. I got a screen protector for about 5 bucks on Amazon (at this link if its still available: Amazon.com: For Google Pixel 2 XL Screen Protector Tempered Glass - [2 Pack] HD Ultra Thin Screen Protector for Google Pixel 2XL [Anti-Scratch] [Bubble Free] ). It says it is tempered.
I took off my old screen protector and left the bare screen exposed for a few days while I waited for the new one to arrive. During these few days I set my phone upside down, left it in my pocket, probably even dropped it knowing me, but the screen remained unscratched. When I got the new screen protector I applied it and everything was fine. A few days later I realized that there were small scratches all over the screen protector, and I wondered what one earth could have caused this?
Mohs hardness scale is the first measurement scale I think of when it comes to testing scratch resistance, and
I have watched a lot of Mohs hardness testing for phone screens, and also some for screen protectors (this video I Broke 17 Different iPhone 12 Screen Protectors. Which One Was Strongest? - YouTube, and this whole channel JerryRigEverything - YouTube are good references if you want to see phone screens and screen protectors tested). Generally glass is glass, and glass scratches starting at a 6 on Mohs hardness scale. (Mohs hardness scale is illustrated in the graphic to the right, but if you want to know more you can visit this link: Mohs Scale of Mineral Hardness (thoughtco.com) ), but even though this is the case there a certainly various hardesses between each level of the Mohs hardness scale, and as demonstrated in the video I linked above it seams that different glass can be scratched less or more easily by a level 6 hardness Mohs pick (Mohs hardness picks are picks made to have certain specific Mohs hardness).
This being said it seems like the issue is likely that I got a low quality screen protector to cover a high quality screen. Ideally I suppose one would want a gorilla glass screen protector, or perhaps a sapphire one (since sapphire scratches at a 9 on Mohs’ scale, although it is more brittle). Even better is if one could customize the thickness of their actually phone screen, as a woman from this video: Inside Corning's Gorilla Glass Factory - Bing video
Says ‘if gorilla glass was made into screens as this as (?) they would be virtually indestructible’.
