The Different Types of Watch Crystals

Watch crystals are the most important building blocks in the construction of wristwatches. They not only make it possible to read the time, but also protect the movement from dust, water, and other dirt buildup and damage. There are various materials for both women's and men's watches, such as acrylic crystal, mineral crystal, sapphire crystal, or hesalite crystal.

Mineral crystal in wristwatches

Here, a distinction can be made between untreated and hardened mineral crystal. Rock crystal and smoky quartz are also closely related to mineral crystal. By adding oxides such as aluminum oxide, mineral crystal can achieve better scratch resistance and hardness. Even so, this material can still be damaged and, in the event of scratches, would not be as easy to polish as acrylic crystal. It could also break, allowing even fine glass splinters to enter the inside of the watch. This is why there can be differences in quality. A good mineral crystal is chemically hardened in a process, making it more impact-resistant and durable than ordinary window glass.

Acrylic crystal

This material is made of a plastic called polymethyl methacrylate. Better known as Plexiglas, acrylic glass, or hesalite glass. This material is very light, relatively shatter-resistant, and easy to polish. One disadvantage, however, is that acrylic crystals can scratch more quickly due to their lower density. Fine scratches can, however, be removed again by polishing. In addition, the material can yellow over time due to UV radiation and aging. A clear advantage, though, is that the dial looks especially clear and natural through Plexiglas. This is because no light is reflected, so there are no distracting reflections.

Sapphire crystal

Sapphire crystal is not actually glass, but a synthetic sapphire. Only diamonds are harder than sapphire - the hardest material in the world. It is therefore especially valued for its scratch resistance and durability. That is why it is also often used for diving watches, which are exposed to high pressure at depths of several meters underwater. If you think your sapphire crystal has a scratch, it is usually only marks from softer materials that can be removed easily. One disadvantage, however, is that if the crystal has not been specially coated, it can cause refraction and unfavorable reflections.

Hesalite crystal

Hesalite crystal is much softer than mineral or sapphire crystal and therefore significantly more prone to scratches. At first glance, this may seem like a disadvantage, but depending on the situation and intended use, it also has some benefits. Its soft nature makes the crystal more flexible, which means that hesalite is much more shatter-resistant than mineral and sapphire crystal. The material is exceptionally impact-resistant. It can crack, but it does not shatter. Another advantage is that smaller scratches can be removed easily with polishing. Another benefit of hesalite crystals is that they are affordable and easy to install. If an acrylic crystal ever needs to be replaced, most watchmakers can carry out the repair cheaply and without hassle.