Generally speaking, tempered glass is the hardest of all screen protectors when it comes to scratch resistance. The main parameter that measures quality of a tempered glass film is its hardness. From an intuitive experience, the harder a tempered glass film is, the better it naturally protects the mobile phone display. Merchants always advertise their tempered glass as “9H” to show that it is a premium quality product, we’ll always find the word “9H” at the most conspicuous location on the product description or carton. So what is 9h hardness screen protector? How tough is it?
WHAT IS 9H HARDNESS?
Many people use the tempered glass today without knowing what 9h hardness is. 9h refers to the Moh scale of mineral hardness. Friedrich Mohs invented this scale in 1812, and it ranges from 1 to 10 with glass around 5 and diamond at the top of the scale.The scale is only represented by numbers with no “H” suffix. The suffix stands for a pencil’s hardness. To calculate a rating you can use the pencil test, which compares the relative hardness of a screen. For example, when a manufacturer claims its screen protector is 9h, it means that the screen can resist scratching from even the most aggressive pencil.
From soft to hard pencil, pencil hardness ranges from 9b to 9h. Naturally, it doesn’t make sense to compare a glass material with a pencil. So we test for hardness using the amount of scratch that the harder pencil leaves on the display. For testing various screens, we use lead pencils with a hardness ranging from 6b to 9h, pressed into the surface at a 45 degree angle. The scores are given by the hardest pencil that does not scratch the surface. The table below shows the Moh scale.
MINERAL | HARDNESS |
Talc | 1 |
Gypsum | 2 |
Calcite | 3 |
Fluorite | 4 |
Apatite (glass falls into this category) | 5 |
Orthoclase feldspar | 6 |
Quartz | 7 |
Topaz | 8 |
Corundum | 9 |
Diamond | 10 |
How tough is the 9h hardness screen protector?
When it’s marketed as being 9H, it has been tested to resist scratches from even the sharpest pencils. Another benefit of the 9H-tempered glass screen protector is its extreme toughness. The table above indicates that glasses have a Moh Hardness of 5-6, so that knives, coins and keys made of copper and iron with Moh Hardness of 3-5 cannot scratch them.
It’s natural to wonder why Corning Gorilla Glass Screens with a Moh of over 6 tend to get scratches. Well, the major cause of screen scratches is sand, which is considered to have a Moh of about 6. But…we’re talking about a hardened glass screen protector with a Moh of 9. This means that no knives, keys, coins, or sand in your pocket can scratch it.
What else to consider when choosing tempered glass screen protector except for the hardness?
In addition to having excellent scratch resistance, a good quality tempered glass screen protector must also have good coverage on the screen, good manufacturing process, back-attachment making the tempered glass screen protector more easy to apply in paste operation, the tempered glass screen protector’s thickness should be moderate; too thick will make for a bad overall feeling in the hand; too thin, the tempered glass screen protector becomes fragile. Besides superior scratch resistance (anti-fingerprint coating), scratch proof performance and drop protection, and light transmission, there are some special but optional features like anti blue light, anti-peeking, etc. It’s up to you whether or not you need them.
