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Watch Crystals

Watch crystals are the protective transparent cover that is found over the face of the timepiece, preventing any moving parts form being exposed to both the wearer and the environment. It is important to note that this crystal component of a watch is not the same as the quartz crystal that is sometimes used to provide power for the watch mechanism. Watch crystals can be made of three different materials, all which are transparent. Plexiglass is found on cheaper watches, and it offers a lightweight option which can be quite easily repaired and buffed to remove any scratches. Standard glass can also be used, providing a strong protective layer over the workings of a watch. This is referred to in the watch business as "mineral glass". Most high end watches have a glass that is comprised of synthetic sapphire, which is a very hard, transparent material made of crystallizing aluminum oxide at very high temperatures. Synthetic sapphire is chemically the same as the natural sapphire used in jewellery but does not possess the colours that can be found in natural sapphire. A watch with one of these synthetic sapphire crystals is rather expensive thanks to the cost of the tools that are required to work with it, as sapphire is an incredibly hard substance, with only diamond and a few man-made substances being harder.

Sapphire crystals are marketed as scratch resistant, thanks to the hardness of the material. This does not mean that it is impossible to scratch these watch crystals, as any harder substance such as diamond would be able to mark the surface. Most watch crystals will not become scratched however and will last the lifetime of the watch. Synthetic sapphire has been around since the nineteenth century and was first used by horologists in watch crystals in 1960. The material is used for the crystals of many high end watches these days, along with Limited Edition watches. Not all scratch resistant crystals are made from synthetic crystal. Due to the fact that both mineral glass and synthetic sapphire looks identical the only way to tell between them is to scratch them with a piece of stainless steel, resulting in the mineral glass scratching. Scratch resistant mineral glass crystals are coated with a range of harder substances to reduce the risk of a scratch occurring. Other coatings can also be applied to crystals, such as "anti-reflective" and "glare-resistant".