Different Types Of Watch Glasses: Which One Is The Best?

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Watch glasses can be called the ribcage of the watches as they protect the dial of your precious watch. And just behind the dial is the highly sophisticated movement or engine of the watch. That’s why you will find most watch enthusiasts pay close attention to the type of glass a watch sports.

Were you thinking that different types of watch glasses are just a marketing gimmick to make more money from you? Well, it’s not. There are mainly three 3 types of watch glasses widely used namely acrylic glass, mineral glass, and sapphire glass. However, you can find some other types of glasses that are exclusive to some watch brands only like hardlex glass in premium Seiko watches.

So how are these watch glasses different and which watch glass is the best? To answer this, I have compared acrylic, mineral, sapphire, hardlex, and Krysterna watch glasses with each other.

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Different Types Of Watch Glasses

1. Acrylic Glass/Hesalite/Plastic Crystal

Vostok watch with acrylic glass
Vostok watch with acrylic glass

I am beginning my list with acrylic glass which is widely used in cheap digital and analog watches. The chemical name for acrylic glass is Poly(methyl methacrylate). Besides normal acrylic nomenclature, some brands refer to the material as Hesalite or Plexiglas.

What sets acrylic apart from other glass materials is that unlike other glasses it is shatterproof. That’s why you will find various sports and digital watches that use acrylic glass. However, these watches can get scratched easily and aren’t as scratch-resistant as mineral or sapphire glass.

Cheap doesn’t necessarily mean bad in fact many Rolex watches used acrylic glass in the past. And, various watches like Vostok, Timex, and more still use them to this day.

One major benefit of acrylic glass is that while it may be a scratch magnet but polishing it can remove the scratches. If done right your watches will always look as good as new. That’s why it is also used in making windows covering the building, solar cells, and various other industrial applications.

The Good
  • Affordable glass material
  • Highly durable glass doesn’t shatter
  • Even used for construction and other material
  • Polishing the glass can remove scratches
The Bad
  • Gets scratched easily
  • Looks not ideal for high end watches

2. Mineral Glass

Fossil watch with mineral glass
Fossil watch with mineral glass

The next glass on the list is mineral glass and without a doubt, you have at least worn or seen a watch with a mineral glass in your lifetime. This is the most commonly used glass material found on watches. They are more expensive to make than acrylic glass but still can be found on affordable as well as midrange watches.

The surface of the mineral glass is heated at a high temperature to make the glass resistant to scratches. And, that’s why they don’t get scratched as easily as acrylic glass. It is also more fashionable and good-looking compared to acrylic glasses. Besides watches, mineral glass is also used in making jewelry, windows, and various other consumer products.

The Good
  • Better resistant to scratches compared to acrylic glass
  • Looks fashionable on watches
  • Mineral glass doesn’t fade with time like acrylic glass
  • Available in midrange watches
The Bad
  • Once scratched you will have to replace the glass or use it as it is
  • Isn’t shatterproof like acrylic

3. Sapphire Glass/Synthetic Crystal/ Flame Fusion

Victorinox watch with Sapphire Glass
Victorinox watch with Sapphire crystal glass

You can’t go wrong with sapphire glass as they are highly scratch-resistant compared to any other glass material. So much so that Sapphire is rated 9 out of 10 on the Mohs scale of mineral hardness. So in a sense, you would need a similar or better material like a diamond to scratch the glass.

That’s why all the high-end premium and top-of-the-line watches have sapphire glass that protects the dial of the watches. However, you shouldn’t mistake scratch resistance with being shatterproof or unbreakable. So while scratches might not be an issue for it but high-speed impacts can definitely damage it.

If durability is your priority then you will find that sapphire glass will tick all the boxes for you. Most watches come with synthetic sapphire because it’s more reasonably priced than natural sapphire and is as good as the original one.

The Good
  • Highly scratch resistant

  • Sapphire glass tend to reflect light better

  • Used in premium and high-end watches
  • One of the strongest glass-like material after diamond
The Bad
  • Expensive glass material

4. Hardlex Glass

Seiko watch with hardlex glass
Seiko watch with hardlex glass for protection

Hardlex glass is exclusively made by Seiko which is a well-known Japanese watch brand. It is prepared by modifying the mineral glass to make it more durable and shatter-resistant. Seiko does that by chemically altering and heating the glass for making the glass more durable.

However, no documentation has been made public by Seiko stating the composition of the glass. In my opinion, Hardlex sits somewhere between mineral and sapphire glass in the durability department.

The Good
  • More scratch resistant than mineral glass
  • Not as expensive as sapphire crystal
  • Can survive day to day abuse with ease
The Bad
  • Mostly used in Seiko watches

5. Krysterna Crystal Glass

Stuhrling watch with Krysterna crystal
Stuhrling leather watch with Krysterna crystal

Krysterna glass is used and developed by the Stuhrling watch brand and if they are to be believed then this glass is more shatter-resistant than Sapphire. However, Sapphire glass is scratch-resistant and not shatter-resistant so there is no way of knowing what this claim means in real-world usage.

But performance-wise most watch enthusiasts expect the glass to offer similar performance compared to mineral glass.

The Good
  • Perfect for those who like Stuhrling watches
  • Little expensive than watches with mineral glass
The Bad
  • Not as good as Stuhrling claims it to be

Mineral Vs Sapphire Crystal: Which One Is Better?

When it comes to being scratch resistant then the sapphire glass is way better than mineral glasses. Sapphire doesn’t get scratched easily whereas mineral glass is comparatively easier to get scratched.

Another benefit of sapphire glass is that it also has anti-reflective properties. So if you will wear the watch with sapphire glass in a bright environment then you won’t find glass reflecting glaring light in your eyes.

Without a doubt, we can conclude that sapphire crystal is way superior then mineral crystal. And, that’s why you will find it being used in premium and luxury watches.

Acrylic Vs Mineral Glass: Which One Is Right For You?

Both acrylic and mineral glass have a unique advantage over each other. Let’s discuss acrylic glass first, this glass is mostly used in affordable watches. And, it is highly shatter-resistant but on the other hand, it is more prone to scratches. However, you can remove the scratches from the glass by polishing it using a cloth.

Another problem with acrylic glass is that they tend to get a yellowish taint with time and there is no way to avoid it. After that, you will need to replace the glass entirely.

Talking about mineral glass, these glasses are more scratch-resistant and hence don’t get scratched easily when compared to acrylic glasses. If by chance mineral glass on your watch gets scratched then you cannot remove it by polishing the glass. The only solution you will have is to replace the glass entirely.

To conclude, I would recommend going with mineral glass because it’s more good-looking, has better protection against scratches, and has better visibility.

Hardlex Vs Sapphire: Which One Is The King Of Watch Glasses?

Hardlex glass is exclusive to Seiko watches and is considered to be more sturdy and scratch-resistant than mineral glasses. But it comes nowhere close to sapphire in that department.

However, one department where hardlex shines is the resistance to shattering entirely. Due to the physical properties of sapphire, they don’t get cracked and if they do then they shatter entirely. Whereas hardlex watch won’t shatter entirely and instead will get cracked first.

Sapphire pulls ahead of hardlex when it comes to reading the time from them. Compared to hardlex, sapphire is highly anti-reflective which ensures easy readability of time in any bright environment. That’s why sapphire is considered to be the best type of watch glass as durability isn’t the only forte of it.


What Is Flame Fusion Crystal?

Flame fusion crystal is just another name for synthetic sapphire crystal made by watch manufacturers. They are similar to genuine sapphire when it comes to durability, scratch resistance, and other characteristics. However, they are cheaper than genuine sapphire crystal glass and that's why they are widely used.

Is Hardlex Better Than Sapphire?

In short no, Hardlex isn't as scratch-resistant as sapphire nor does it exhibit anti-reflective property as sapphire glass. So given the option to choose between the two, sapphire glass will always be the better choice.

Which Glass Is Best For Watches?

Sapphire glasses are considered to be the best type of watch glasses for watches because they don't get scratched easily and are rated 9 on the Mohs scale of hardness.

Is Sapphire Glass Better Than Mineral Glass?

Sapphire glass is way better than mineral glass as the latter is rated 6 out of 10 on the Mohs scale of hardness whereas sapphire is rated 9. That makes Sapphire better in terms of durability and hence making it more scratch-resistant.

Tom Nielson

Tom's love for watches started when his grandfather gifted him his Rolex watch when he turned 18! Being a teenager it was a big deal for him. Later when he got his first job he bought Fossil Palm Pilot back in 2003 which was a smartwatch. Since then smartwatches have come a long way and so is Tom's love for them. His experience with watches inspired him to start Wearholic and share his knowledge of wearables including watches, smartwatches, smart glasses, & smart clothing.

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