There are different types of Watch Crystals (a list of lower quality to high quality)

Plastic glass
A light type of glass which makes it very difficult to break. It is absolutely not resistant to scratches and you immediately notice the durability.
Mineral glass
Mineral glass is stronger than glass made of plastic. The disadvantage of mineral glass is that it can be fragile. It is less sensitive to scratches than plastic glass, but it is certainly not scratch-resistant.
Crystal
Crystal is again a degree stronger than mineral glass. Thanks to its hardness it is more resistant to scratches.
Sapphire Crystal
The ‘Bentley’ of watch crystals is ... sapphire crystal. Sapphire crystal is a synthetically produced crystal second only to diamond in its hardness, making it extremely durable. It is typically grown in cylindrical sticks called boules, and is slow, expensive and energy-intensive to produce. Sapphire crystal is therefore highly resistant to scratches. Almost all luxury watch brands make use of this type of watch crystal thanks to its excellent qualities. It’s the best protection a watch face can have but it has of course a slightly higher price tag.
Take a look at our selection of luxury watches with sapphire crystal.