9H means the protector wasn't scratched by the hardest pencil in the standard pencil hardness test. It is not the 9 on the Mohs mineral scale. Almost all tempered glass passes, so 9H tells you very little. Sand can still scratch a 9H protector.
The pencil hardness test
The test drags pencil leads of increasing hardness across a surface at a set angle and pressure. Grades run from soft (6B) through HB to the hardest, 9H. A surface rated 9H wasn't marked by a 9H lead. It's a coatings test designed for paints and plastics, where the difference between grades means something. For glass, it's a low bar.
9H vs the Mohs scale
| Material | Mohs hardness |
|---|---|
| Pencil lead (graphite) | About 1–2 |
| Fingernail | About 2.5 |
| Coins, keys (steel) | About 4–5.5 |
| Typical glass | About 5.5–6 |
| Sand, quartz | About 7 |
| Sapphire | 9 |
Graphite is one of the softest materials there is, so it can't scratch glass however "hard" the pencil grade. The number that matters for real-life scratches is the Mohs figure: anything harder than glass, particularly quartz sand, will scratch it. That includes a 9H protector, and your phone's own glass.
What to compare instead
- Adhesive coverage: full adhesive avoids air gaps and fingerprint problems.
- Edge finish: rounded "2.5D" edges resist chipping and feel smoother.
- Oleophobic coating: decides how easily smears wipe off. See oleophobic coatings.
- Fit and tray: the most common cause of a bad experience is a crooked or wrong-model fit.
Questions people ask
Is 9H the hardest screen protector?
No. 9H is the top pencil grade, and nearly all tempered glass achieves it. It says little about real-world scratch resistance.
Can a 9H screen protector be scratched?
Yes. Sand and other materials harder than glass will scratch it.