Shellrus Sapphire X
When we search for screen protectors online, "9H" pops up frequently. You might have been wondering, as a measure of hardness, how hard is "9H"?
In fact, "9H" is a misleading advertisement because it is defined according to the hardness scale for a pencil. Obviously, graphite will not be harder than glass.
Here, it comes the Mohs' scale of mineral hardness. The Mohs' scale is a qualitative ordinal scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material (Wikipedia). It defines talc as level 1, diamond as level 10. Here is the Mohs' hardness table for items you might be interested in:
Quartz is a level 7 on the Mohs' scale, and it commonly exists as sand and dust around us.
Gorilla glass and any other tempered glasses can be scratched easily by sand.
Sapphire, on the other hand, won't be scratched by anything except diamond, and we did a sandpaper test to demonstrate this concept.