The watch crystal is the single most exposed area on your watch. Therefore it must be tough and scratch resistant. In diving watches it must be able to withstand great pressure, in aviation watches be able to withstand negative pressure, whilst at all times remaining clear and legible to the wearer.
Many people, when looking for a watch, tell us that they only want a sapphire crystal as they believe this is the best. However, this is not always the case. There are three types of watch crystal available today, and each offers something different.
But first a little history lesson.
In the early days of watch making, all watches were fitted with mineral glass. This is the same type of glass that you will find in your car, home or office. Mineral glass is tough, has good clarity and most importantly should not shatter.
This is exactly the reason that Elliot Brown watches actually specify mineral glass in their range of go-anywhere, do-anything watches. If damaged, mineral glass will remain intact and allow the user to continue using the watch without risk to the watch movement or the ability to keep time being impacted. This decision was born out of their many years of practical experience in creating tough watches for tough situations. The same thinking was behind their decision to use triple gaskets instead of screw down crowns. An Elliott Brown watch is built to ‘wear and forget’, a watch that you don’t have to worry about.
In the mid twentieth century plastic technology was maturing and the acrylic crystal was developed for watches. Acrylic had three benefits:
1. They were tough, probably tougher than mineral glass.
2. They were slightly flexible and could be ‘tensioned’ when mounted onto a gasket and this made them ideal for early diving watches because a tight fit for the crystal ensured a good resistance to water pressure.
3. Whilst they were softer than mineral and more easily scratched, unlike mineral or indeed sapphire crystals, they could be polished and brought back to a superb level of clarity without replacing the crystal itself.
And to us, acrylic crystals are cool!
If you are like us and you just love wearing your watch and not ‘keeping it in a safe’ then the ‘patina’ of an acrylic crystal is a wonderful thing to behold. It adds real character to a watch. Think about it like an old pair of faded denims with your favourite shirt, and then you’ll get the idea. One other hidden benefit is that the acrylic crystal watches lurking in manufacturer’s collections are often fantastic buys. Take the Sinn 103 or 356 both great watches, bursting with vintage character and full of Sinn’s aviation watch heritage and all at an accessible price. How many watchmakers do you know who would have a heritage piece in their range and not charge double for the privilege of owning it?
Finally, we reach the sapphire crystal. Sapphire crystals are made from mono-crystalline aluminium oxide (Al2O3). Famed for its superior scratch resistance, sapphire crystal offers better day-to-day scratch resistance than either mineral or acrylic crystals and although can shatter if damaged by a sudden impact, it offers fantastic clarity and durability.
Now at this point let us stress. We’ve sold watches to mountain rescue teams, civil and military pilots, armed police response units, wildlife cameramen and even watch fans who, never venture far from a nice cup of coffee and a computer screen. In all these we have yet to replace a crystal of any type. Rest assured at Page and Cooper if you choose any watch with crystal we are here to make sure your outlook on time is always, crystal clear!