Compliance with the device class
In the first place, the characteristics of the glass must correspond to the class of the device in which Shockproof waterproof watches are most often equipped with sapphire glasses. Watches for everyday wear and sports are usually equipped with mineral and plastic glasses, less often sapphire. You should not expect expensive sapphire glass to be installed in the budget device.
How to distinguish expensive glass from simple mineral
can apply a water droplet on the wristwatch glass. Tilting in different directions the clock with mineral glass can be noticed that the water droplet is spreading, leaving behind a trail, the so-called tail. Such with a drop of water does not occur on sapphire glass: even when the clock is tilted in different directions, a drop of water does not grow on the surface of the glass, and rolls on it like a mercury ball – without a tail. If the experiment is conducted with sapphire glass with anti-glare, the water drop will remain in the same place where it was put, even when the device is turned down by the glass. The difficulty of the experiment is to choose the size of the drop correctly.
The second method of inspection is not always possible when buying the product, for example, to try scratching the glass. The sapphire coating isn’t scratched, but it’s easy to smash. In the conditions of the store you can check the glass for glare: mineral gives them, sapphire no. If the watch is equipped with anti-glare glass, it is not possible to know whether it is sapphire or mineral, as both appear invisible, that is, do not reflect light. Both the coating have a bluish hue.
The truest and most accurate way to distinguish one glass from another is to take turns to bring each one to the tip of the nose and hold a few seconds. The colder material and will be sapphire, as it is slower to heat than the mineral. If both are heated evenly, it is safe to argue here that both glasses are mineral. However, this experiment can be carried out with two devices, about one of which it is precisely known that it is equipped with a coating of mineral glass.