Different Watch Crystals and Their Benefits

Watch crystals are the most important building blocks in the construction of a wristwatch. They not only allow you to read the time, but also protect the movement from dust, water, and other dirt buildup and damage. There are three materials: plastic crystal, mineral glass, and sapphire crystal.

Mineral Glass

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

Plastic Crystal

This material is made of a plastic called polymethyl methacrylate. Better known as Plexiglas, acrylic glass, or Hesalite. This material is very lightweight, relatively impact-resistant, and easy to polish. One drawback, however, is that plastic crystals can scratch more quickly due to their lower density. Fine scratches can, however, be polished out again. In addition, the material can yellow from UV radiation and age. A clear advantage, though, is that the dial looks especially clear and natural through the Plexiglas. This is because no light is reflected, so there are no distracting reflections.

Sapphire Crystal

Sapphire crystal is actually not glass at all, but a synthetically produced 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 strong 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 drawback, however, is that if the crystal has not been specially coated, it can cause light refraction and unfavorable reflections.