Originally Posted by durangojim
Big debate on this one, but I will be using a protector. All it takes is one grain of sand and a little force in your pocket to cause a scratch. All those key "tests" you see on youtube are total BS as metal can't scratch glass. You never see any of them take sandpaper though as quartz is harder than glass.
Exactly. Hardened steel has a hardness of ~ 6.5 on Moh's scale (Silica- glass- is a 7), and key metal is much softer than hardened steel.
That said however, metal can and will still mark glass (and oleophobic coatings on glass
) briefly if a sufficiently sharp point with enough reinforcement and enough force can "hook" enough SiO2 molecules as it drags across- but it will degrade/fail/bend quickly. In fact, "dirt" (potentially silica dust) on the edge of the key is of more danger than the key itself. Most of the minor scratching we see is probably due to dust (airborne silica and other hard mineral particles) being caught on whatever surface the screen is being dragged across.
Also, get a protector, after a week and a half now mine is already scratched (not badly, just annoyingly).