Updated August 2026 Look at almost any tempered glass screen protector listing and you will find "9H hardness" printed somewhere, often next to a diamond icon. The implication is obvious: 9 sounds close to 10, diamonds are a 10, so this glass must be nearly diamond-hard and nearly scratch-proof. Almost none of that is true, and the way 9H gets used is one of the most persistent bits of misleading marketing in phone accessories. The spec is real, but it comes from a much humbler scale than most buyers assume. Here is what 9H actually measures, why it is not...