Sapphire glass, mineral or acrylic, which glass to choose for your watch ?

When one wishes to acquire a watch, We can examine the glass from which it is made. In watchmaking, it There are three categories of watch glass; acrylic glass, mineral glass and sapphire glass. What are the differences? What are the differences between these three types of watch crystals used in the watchmaking industry? In this article, we will present their specific characteristics, their advantages, and their potential disadvantages.

• Acrylic watch glass or Hesalite glass: Acrylic glass is a type of glass derived from the plastic commonly known as Plexiglas. The advantage of this type of glass is that it is extremely lightweight and economical. However, it is not very impact-resistant and breaks easily. It also scratches much more easily than other types of glass, but it is easy to clean. of the polish again. Acrylic glass has a Vickers hardness of 500 which remains relatively low, the Vickers hardness being an index measuring the strength of materials.
• Mineral watch glass: Mineral glass is much more robust than acrylic and is the most commonly used glass in watchmaking. It is glass in the classic sense of the term, meaning it is not a chemically produced compound. Although mineral glass is heat-treated to be scratch-resistant, it can, after significant friction, It can scratch. Unlike acrylic glass, mineral glass is more difficult to polish again, and the entire glass will need to be replaced. The same applies in the event of a significant impact. This type of glass can break, although it's not common. Mineral glass has a Vickers hardness ranging from 650 to 800. In short, mineral glass is robust but can become damaged after a few years.
• The sapphire watch crystal: Sapphire glass is a compound that is created in the laboratory. More expensive to produce than the glasses studied previously, sapphire glass is obtained from...aluminum oxide Crystallized at a very high temperature (2050°C to be precise), it therefore possesses the same chemical properties as natural sapphire. Thanks to these chemical properties, sapphire glass is a very hard and resistant material. (Vickers hardness equal to 2300), It is the second hardest material after diamond. For comparison, it is also seven times harder and stronger than tempered steel. Therefore, sapphire crystal is extremely difficult to break or scratch.

Watch glasses at Charlie Paris

At Charlie Paris, all our watches automatics are equipped with a Sapphire crystal is used to ensure maximum longevity. It's worth noting that the thickness also affects the impact resistance of a watch crystal. The thicker the glass, the stronger it will be. On our sport models, We have therefore chosen to offer them with a thicker sapphire glass than on our city models.

ATTENTION ! Just because your watch crystal is very resistant doesn't mean the inside is too. So, if you drop your automatic watch with a sapphire crystal, it will appear intact on the outside, but the movement's inner workings may have been damaged by the impact. It will be necessary to... SO to take it to your watchmaker to have it serviced.It's important to have a watch with a quality crystal, but that shouldn't stop you from treating your watch with the utmost care!