Consumer Reports, the one that took sides in the well-known Antenagate, is testing the sapphire glass screen of the Apple Watch and the results are being surprisingly good. After the tests they conclude that the glass of the Apple Watch Sport is scratched, yes, but only after exceeding 7 Mohs (hardness scale), which is unlikely to ever happen.
On the other hand, the Apple Watch of any of its versions that include sapphire glass (the steel one and the Edition) does not scratch under any circumstances (except with Diamond, which is considered harder). In any case, for all practical purposes, it is unlikely that you will ever scratch your Apple Watch with sapphire crystal..
The sapphire crystal has turned out as strong as expected, which boils down to a lot. The sapphire one would respond to an attack of 9 on the hardness scale, the Sport version, which raises a modified glass, would withstand up to an attack of 7 on the hardness scale. Therefore, the sapphire glass of the Apple Watch versions is undoubtedly stronger than the reinforced glass of the Apple Watch Sport., but this second is the one that has caused a surprising performance, which we hope will be reflected in future iPhones. In fact, the Apple Watch Sport raises a glass so powerful that it would rank eighth on the Mohs scale, just below sapphire, equivalent to topaz.
In addition, Consumer Reports also carried out some tests on the Apple Watch sensors, showing up to now really reliable in the measurements. They have also submerged the Apple Watch in water for thirty minutes at a depth of about 3 feet, confirming that its resistance rating corresponds to the reality of the device.