When shopping for a watch, it's easy to get lost in all the options: chronographs, military tactical watches, strap choices, waterproof watches, skeleton windows—the list goes on. But one piece often overlooked (literally) is the watch crystal. It's that all-important layer that sits between you and the dial, protecting your precious timepiece from everything life throws at it. Whether that's the occasional bump on your office's door frame or a seismic smash when you wipe out on your mountain bike–your watch's crystal protects it. Given what most people put their watches through, that's no small job. Without the crystal, your watch would be a mangled, water-logged mass of twisted hands and broken dreams.
Let's look at everything you need to know about these under-appreciated watch components. Here's why watch crystals matter and which type might be right for you.
What is a Watch Crystal, Anyway?
A watch crystal is the transparent cover over the watch's face. Put another way, it's the window through which you view your watch. It's also the barrier between you and all those delicate gears, movements, jewels, dials, and windows. Your life generates dust, dirt, sweat, splashes, and projectiles. All of these are Very Bad for a watch. The crystal is the barrier keeping them out.
Even if it gets scratched, dinged, or foggy, a crystal can still protect your timepiece. But it's not going to look very good and can interfere with your ability to quickly read the time or other information offered by your watch. The trick is finding a crystal that's tough enough to handle everything you may throw at it, drag it through, or bounce it off but still give you a clear, unobstructed view of your watch and its beautiful face.
There are three common types of watch crystals: acrylic, mineral glass, and sapphire. Each has strengths and weaknesses. Let's examine the three contenders so you can see which might be best for you:
Acrylic
Acrylic is the OG of watch crystals. This material is a type of plastic. Most acrylic crystals are Polymethyl Methacrylate (PMMA). It's the gold standard for acrylic crystals. PMMA is lightweight, affordable, and strong. It's the honeybadger of watch crystals–amazingly tough and willing to take on anything.
PMMA's toughness means it's exceedingly difficult to break. It can handle a smash against your weight bench without cracking. An aggressive interaction with dirt when you wipe out on your bike? Like the honeybadger, PMMA don't care.
While it can take some lumps, acrylic is easier to scratch than some other crystal materials. These scratches can give it a hazy appearance as minor scratches add up. Thankfully, a skilled watch repair person can usually buff out small scratches with a bit of polish and elbow grease.
PMMA crystals are commonly used in military tactical watches or models demanding durability. If you want a watch crystal nearly as tough as you are, acrylic--specifically PMMA--should be your focus. This lightweight, shatter-resistant, wallet-friendly option is well worth a look.
Mineral Glass
Next, let's raise our glasses in a toast to mineral glass. This crystal is a popular choice for moderately priced watches. Mineral glass is heat-treated glass. The heat makes it tougher than the standard glass in your wine glasses or windows. While it's more expensive than acrylic, mineral glass isn't a budget buster.
This material can handle everyday wear and tear. It's not likely to get scratched if it goes a couple of rounds in your pocket with your house keys, but it is still somewhat susceptible to scratches. Unfortunately, unlike PMMA, you can't simply buff your mineral glass scratches. Once they are there, they are there for good. So, while it's harder to scratch than its acrylic cousins, your mineral glass crystal's battle scars won't fade once they are there.
Its ability to withstand brutal hits without shattering and brush off many blows that might scratch acrylic makes it a solid option for those who want durability. Its moderate cost also makes acrylic crystals an attractive choice for many mid-range watches.
Sapphire Crystal
Sapphire crystal is a luxe powerhouse. It's the top-of-the-line watch window. It can be confusing to have the word "sapphire" in something that we want to be clear and nearly colorless. Sapphire crystals are made from synthetic sapphire. This material is lab-created, and clear and nearly colorless unlike the mined blue gemstones that come to mind when you think of sapphire.
Sapphire ranks as a nine on the Mohs hardness scale. That's just shy of diamonds' 10 score, meaning your sapphire crystal is almost as hard to scratch as a diamond.
All that toughness does come with a higher price tag, which will often be reflected in the cost of the watches these crystals adorn. Putting such a high-end crystal on an otherwise cheap watch usually doesn't make sense. This material is generally saved for a luxury or high end watch.
If your watch is a status symbol, point of pride, or investment piece, sapphire should probably be your crystal of choice. Because it is nearly scratch-proof and incredibly clear, it helps ensure you'll always have an unobstructed view of that watch face you paid good money for. While it can still shatter if it takes a hard enough hit, breaking a sapphire crystal takes quite a lot of focused energy. That means your watch is well-protected.
Watch crystals are more than just pretty pieces of glass or plastic. They are the windows to your watch. They keep your timepiece looking sharp and functioning well. Whether you're a fan of the buffable acrylic style, the versatile mineral glass, or the luxurious sapphire, there's a crystal that fits both your lifestyle and budget.
