“9H” is one of the most common marketing terms on screen protectors, yet its real meaning is surprisingly widely misunderstood – even by manufacturers themselves. It does not describe the absolute hardness of the material, but the result of the pencil hardness test – a test in which graphite pencils of different hardness are drawn across the surface at a 45° angle under constant pressure. If the surface withstands even the hardest standard pencil (9H), it earns the label. In other words: 9H tells you only about resistance to pencil lead – not about what sand in your pocket or a drop onto the pavement will do to the glass.
Where does “9H” come from?
The pencil hardness test was originally developed for testing paints and industrial surface finishes, not glass. The ASTM D3363 standard, first published in 1974 and last revised in 2022, describes the methodology of this test. In Europe, the parallel standard is ISO 15184, which describes an identical methodology. Screen protector manufacturers adopted it because it is cheap, fast and easy to communicate. “9H” thus became shorthand for “the maximum the pencil test can verify” – not for the absolute durability of the material.
Why does confusing the two scales matter?
The Mohs scale (1–10) puts diamond at 10, corundum (sapphire) at 9, and ordinary glass around 5–6. Tempered screen protectors for phones typically reach 6–7 on the Mohs scale – not 9. The hardest standard pencil (9H) corresponds to roughly 3 on the Mohs scale – about the same as a human fingernail (2.5 Mohs).
For perspective: brass and steel keys sit at 3–4.5 on the Mohs scale – tempered glass is harder, so a key physically cannot scratch it. What can scratch it is the quartz in dust and sand (7 Mohs), which is everywhere in pockets. This very mix-up is one of the most widespread marketing myths.
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Myth “9H means the same as 9 on the Mohs scale, so the glass is almost as hard as diamond.” |
Fact 9H is the maximum of the pencil scale and corresponds to roughly 3 Mohs – far more ordinary materials than diamond can scratch the surface. |
What about “10H”, “12H” or “11H”?
Ratings above 9H appear on the market regularly, but they are not standardised values. The pencil scale ends at 9H – there is no “10H” pencil hardness test. Claims of this kind are purely marketing and cannot be verified by any standardised method. And just as with 9H, none of it means unbreakable: glass can resist scratching and still be fragile in a drop.
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Beware of marketing Claims of “10H”, “12H” or “Super 9H” are not standardised. No recognised standard for these values exists – the pencil scale simply does not go higher than 9H. |
A cross-section of a screen protector – the properties that actually decide
The diagram below applies to the EasyGlass range. The number of layers differs by range and model – Mobile Origin screen protectors have 5 to 7 layers, and premium variants additionally combine CSG military glass with OCA optical adhesive.
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01 Hard coating – top surface protection The first line of defence. A hard surface coating resists direct scratching. |
scratch resistance |
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02 Oleophobic layer Repels fingerprints and grease and keeps the touch response clean. |
fingerprint protection |
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03 PET carrier layer Holds the shards together if the glass breaks – much like the film on safety glass that stops fragments from scattering. |
protection when broken |
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04 Absorption layer (EasyGlass) Cushions the impact of a drop. Applies to the EasyGlass range; other ranges have a different layer composition. |
impact resistance |
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05 Tempered glass 0.2–0.4 mm · 9H pencil hardness · 6–7 on the Mohs scale. |
9H hardness |
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06 Silicone adhesive Provides adhesion without leaving permanent residue. The full glue variant eliminates the air pocket. |
adhesion |
Conclusion: what to look for beyond “9H”
The 9H rating is a good indicator that the glass surface will withstand everyday surfaces such as pens, fingernails or softer plastics. It does not, however, guarantee resistance to harder materials – the quartz in dust and sand (7 Mohs) can scratch the glass. Resistance to cracking in a drop depends on entirely different parameters.
Practical proof of quality comes from tests that go beyond the number 9H: Screen Guard and EasyGlass protectors from Mobile Origin pass a 10,000-cycle steel wool test (steel wool has a hardness of 5–6 Mohs, just below that of the glass – a demanding practical abrasion test). It is the combination of layers, a precise cut and edge durability that determine the real protection of your phone.
Mobile Origin protectors combine a 9H base with an oleophobic finish, easy bubble-free installation (an applicator in the box), full-display coverage and a spare protector in the same box – because no surface lasts forever.
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“9H” is a good baseline, but definitely not the only indicator of quality. The key is the combination of layers, a precise cut and edge durability – plus a spare protector in the box in case the first one has done its job. |
Sources and references
[1] Android Police (2024) – screen protector hardness guide
[2] INAIRSPACE (2026) – 9H Hardness Tempered Glass Screen Protector: The Complete Buyer's Guide
[3] INAIRSPACE (2026) – Glass Screen Protector Hardness Scale Explained
[4] XIMAND (2025) – 9H Hardness: Marketing Hype or Real Protection?
[5] DetailingWiki – What is the Pencil Scale
[6] REWA Technology – Tempered Glass Screen Protector Test & Review
[7] ASTM D3363 – Standard Test Method for Film Hardness by Pencil Test (published 1974, revised 2022)
[8] ISO 15184 – Paints and varnishes: Determination of film hardness by pencil test (the European equivalent of ASTM D3363)