What is the watch crystal?
Obvious to all the watch experts out there, maybe not so to those who know little about the watch world. The watch crystal is the term used for the transparent glass that covers the watch dial or the ‘face’ of the watch. It is designed to protect the watch functions from the elements but also should complement the watch aesthetically and provide and polished finish to the visual.
Geckota Pioneer Aurora Automatic watch with a curved sapphire crystal. Image Credit: Geckota
What is the watch crystal made of?
There are three different materials that are used to make a watch crystal. Often you may hear the term ‘Plexiglass’ thrown around when it comes to watch crystal. This is essentially a type of acrylic crystal that is an extremely strong form of plastic. Watches that tend to have these types of crystals are generally much more affordable, however, do not worry that this is the sign of a fake as some may do, many vintage watches also come with this type of crystal. If you are precious about your watch though this is not the crystal for you, it is extremely scratch-prone.
Acrylic glass does have some advantage points. It is extremely lightweight, budget friendly and if you drop it the crystal is not going to cost you an arm and a leg to fix. It’s a great contender for a kid’s watch as, let’s be honest they are very likely to be dropping them time and time again.
Timex Mercury. Image Credit: WatchGecko
Mineral crystals are seen more often than Plexiglas crystal. They are slightly more durable than any acrylic crystal but are still more prone to scratching than any sapphire crystals. This is also a popular choice for many entry-level watch brands due to it being cheaper and providing better protection than any acrylic crystal. However, these types of covers are still prone to breaking easily, scratches may be able to be buffered out but 9 times out of 10 it will need replacing.
Similarly to sapphire crystals mineral crystal are reflective. These can be treated with an anti-reflective coating or anti-glare treatment, and this will help get rid of any glare that affects the visibility of your dial.
Sapphire crystals are the most durable and scratch-resistant of all watch crystals – in my opinion this would be the crystal I would want to protect my timepiece. However, with great quality comes cost and these are the most expensive crystal for good reason. Sapphire crystals are most commonly made of synthetic sapphire which possess the same hardness as natural sapphire (the second hardest material in the world). To produce a synthetic crystal, it is heated to form round masses which pieces are sliced from then ground and polished to create your watch crystal. Tools needed to cut and polish this type of material are expensive hence why you’ll pay more for a sapphire crystal. Sapphire crystal is very highly regarded in the watch industry and truly revolutionised watch crystals.
Sapphire crystals are highly reflective just as a mineral crystal. If you are buying a watch with sapphire crystal, I would highly advise purchasing one coated with an anti-reflective coating. Most luxury watches will have an AR coating under the crystal as this avoids any scratching on the crystal surface as any sapphire crystal with AR coating over the top are prone to scratching.
Boldr Venture Field Medic II Destro Chronograph Watch. Image Credit: WatchGecko
Can you tell the difference?
The best way of distinguishing what type of crystal your watch possesses is its original price point. You can expect to be paying much more for a Sapphire crystal watch. Otherwise, there is no truly fool proof way to distinguish the 3 without scratching the surface and this is not recommended, only do so at your own risk and be aware that if your watch crystal is mineral or sapphire and does get scratched this can be a costly repair! If tapped an acrylic watch will make a different noise than a mineral or sapphire would.
To tell sapphire and mineral apart is a different matter altogether. For some they can tell by a simple touch. Both should be cool to touch; however, a mineral crystal shouldn’t be as cool as a sapphire crystal, vague, I know! You can also test using water. A drop of water on a sapphire crystal should create a definite blob whereas on a mineral crystal it should spread. The best way to do so (and by far the easiest) is to find your watch serial number and do some online research, the most damage proof way of discovering the crystal on your timepiece.
On the left: MoonSwatch with an acrylic (Plexiglas) Crystal. On the Right: Omega & Bulova with sapphire crystal. Image Credit: WatchGecko
Which Crystal is best for you?
Personally, and I think many others will veer towards this option too, a sapphire crystal is unbeatable in both quality and assurance. It will ultimately cost you more, but it assures legibility and will also help hold the value of your timepiece. However, saying this, mineral also does a pretty decent job at protecting your timepiece and it entirely depends on your budget and what your watch’s purpose is. If it’s there to sit pretty, then you’ll probably be fine with a mineral crystal. Going rock-climbing? A sapphire crystal would be much better suited. Even a Plexiglas crystal serves a purpose, for a child’s watch these are ideal as they can be damaged without costing too much. You shouldn’t always shy away from a Plexiglas crystal, many vintage watches have these, and it can sometimes create a much better aesthetic for a vintage watch, just be mindful it is more prone to breaking!