Here’s everything you need to know about Hardlex crystal and how it compares to other dial-protecting materials.
When you browse Seiko’s range of mid-priced watches, it’s hard to miss the Hardlex crystal top. It’s featured in many of the best Seiko watches.
After all, the brand is famous for creating budget-friendly watches; part of that is its cost-cutting materials. But don’t let that put you off; there’s more to Hardlex than meets the eye.
Hardlex isn’t the only material manufacturers use to shield a dial, but it’s up there with some of the best. In this article, I’ll outline what Hardlex crystal is and how it compares to other watch glasses on the market.
Table of Contents
What Is Hardlex Crystal?
Seiko Hardlex crystal is a proprietary material that Seiko develops in-house in its Japanese ateliers.
You may already own a Seiko. Or, you may be going through the research process of buying one. If you are in either of these scenarios, you have likely come across the term “Hardlex” and wonder what it is.
Sometimes, this material comes with an anti-reflective coating, sometimes not. Either way, the manufacturing process is the same. Seiko heats and chemically treats ordinary glass, increasing its resistance to shattering.
Thanks to this stronger, modified glass version, it’s also more scratch-resistant. Interestingly, Seiko features this crystal throughout its catalog, mainly in the brand’s entry-level wristwatches, but not always.
Higher-end designs tend to feature sapphire crystal, which we’ll cover shortly. But there are some instances where we see the opposite. Seiko sometimes uses Hardlex at a price point that other brands use sapphire crystal.
For example, the Le Grand Sport SKK637 is in the brand’s $150 range and has a sapphire crystal front. So, at least in the mid-tier range, Seiko’s loyalty to its own Hardlex isn’t just about cost. Similarly, Seiko outfits more expensive watches in its catalog with Hardlex.
It suggests that Hardlex is not the cost-cutting manufacturing strategy many believe it is.
Seiko has been using this material since 1980 and has found ways to improve its hardness, like using Boron. Boron has a hardness of 9.5 on the Mohs scale. So, it’s no surprise that the brand uses it to harden its Hardlex material further.
Hardlex Crystal vs Sapphire Crystal
Sapphire crystal is the gold standard of dial-protecting materials. It can appear as a dome-shaped sapphire and is often seen in high-end designs.
Sapphire crystal is actually a ceramic material produced inside a lab. Manufacturers take powdered aluminum oxide and heat treat it under intense pressure.
On the Mohs scale, sapphire scores high, coming second hardest to a diamond. In fact, diamond-coated saws are the only things that cut sapphire crystal.
Manufacturers favor sapphire over mineral glass for its strength and scratch resistance. Because it’s also so thin, manufacturers can treat it with layers of anti-reflective technology.
The disadvantage, of course, is that it’s expensive. Yet many collectors would argue that paying the extra for a quality material is worth it tenfold.
Despite looking similar to Hardlex, Sapphire is much more scratch-resistant. However, it’s also more likely to shatter compared to Hardlex and is the more expensive of the two.
Some military watches feature acrylic crystals or mineral glass as standard practice since scratches are better than shatters.
One thing to watch out for is brands that add a layer of sapphire to their mineral crystals and call it “sapphire.”
The term can be misleading, and although not untrue, it can catch collectors out. Also, sometimes sapphire can refract the light a lot, which creates distortion when looking into the dial.
Consider mineral glass if you plan to wear your watch in conditions where the glass may shatter. You’ll need a watch with impact resistance. If you’re not planning to engage in activities that subject your watch to shock and impact, sapphire is better.
Hardlex Crystal vs Acrylic
The name “acrylic crystal” is misleading since this material is not crystal at all. As a matter of fact, it’s just plastic. That said, acrylic has advantages in that it is much cheaper than mineral glass and sapphire crystal.
It’s lightweight, and since it’s plastic, it won’t shatter easily, but it will still scratch up. Acrylic is weaker compared to Hardlex, but it’s also more cost-effective to replace if it is damaged.
If you’re looking for an affordable watch that is likely to come into contact with impact, acrylic is a good option. But it’s a million miles away from the quality and refinement of a sapphire crystal glass.
The more familiar you become with luxury watches, the more noticeable the differences between affordable and expensive materials become.
FAQs
Learn a little more about Seiko’s proprietary Hardlex material with these FAQs.
Is Seiko Hardlex As good as Sapphire?
Seiko Hardlex is not as good as sapphire in terms of hardness and scratch resistance. It is, however, very durable in its own right and proves more affordable than sapphire.
Sapphire boasts superior scratch resistance, making it a popular choice for high-end watches.
Can You Replace Hardlex Crystal?
Yes, you can replace Hardlex. It’s always best to replace a damaged Hardlex glass with the same glass because the material is exclusive to Seiko.
What Is the Mohs Hardness of Seiko Hardlex?
Hardlex crystal has a Mohs level of 7 on the hardness scale. While not as hard as sapphire crystal, it’s still adequate for most mid- to high-priced Seiko watches.
Wrapping Up: When To Choose Hardlex Crystal
Hardlex is Seiko’s proprietary dial-protecting material. It’s cheaper than lab-developed sapphire, but that’s not the only reason the brand uses it. Hardlex offers impressive toughness, which Seiko further hardens with additional technologies.
Although Seiko uses sapphire crystal glass in its high-end watches, it also uses sapphire in its budget timepieces.
It shows that Seiko doesn’t reserve Hardlex solely for budget watches. The brand also uses it in some expensive watches. This suggests that both materials are almost on par with one another in some aspects.
While Hardlex is scratch-resistant, sapphire trumps it with a hardness of 9 on the Mohs scale.
But Hardlex is still a step above the regular mineral glass. Overall, Hardlex is more scratch-resistant than standard mineral because it benefits from proprietary heat treatments.
It’s a fine choice for many Seiko watches. But for an altogether premium timepiece, sapphire will shield a dial from various scratches and damages.
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