There are 3 categories of watch glass, acrylic glass, mineral glass and sapphire glass.
Acrylic glass is a glass derived from plastic commonly called plexiglas. The advantage of this type of glass is that it is extremely light and economical. However it is not very resistant to shocks and breaks easily. It also scratches much more easily than other types of glass but it is easy to polish it again. Acrylic glass has a Vickers hardness of 500 which remains relatively low, the hardness of Vickers being an index measuring the strength of the materials.
Mineral glass is a much more robust glass than acrylic and is glass most used in watchmaking. It is a glass in the classical sense of the term, in the sense that it is not a compound derived from chemistry. mineral glass although heat-treated to be scratch-resistant can, following significant friction, scratch. Unlike acrylic glass, mineral glass will be more complex to be polished again, it will then be necessary to change the glass in its entirety. Similarly in case of major impact this type of glass can break even if it is not common. Mineral glass one has Vickers hardness ranging from 650 to 800. In short the mineral glass is a sturdy glass but can be damaged after a few years.
Sapphire glass is a compound that is created in a laboratory. More expensive to produce than the glasses studied previously, the glass sapphire is obtained fromaluminium oxide crystallized at very high temperature (2050 ° to be precise), it therefore has the same chemical properties as the natural sapphire. Thanks to its chemical properties, sapphire glass is a very hard and resistant component(Vickers hardness equal to 2300), it is the second hardest component after diamond. By way of comparison, it is also 7 times harder and solid as quenched steel. So sapphire glass is a glass that breaks or scratches very hard, and the perfect companion for your show man or your show woman.
Generally,automatic watches are all protected by aglass sapphire, to ensure the best possible longevity. This is the case for the automatic watches ofCharlie Parisand more particularly for all of our sports watches, who will be able to accompany you for many years.