Understand the different types of watch glasses.

Welcome to the PSB WATCHES blog, your dedicated guide to the captivating and complex world of watches. Our mission is to enlighten you on the intricacies and wonders of watchmaking, an art where every component counts and most importantly, help you choose the ideal watch that suits you perfectly.

Today, we focus on an often underestimated but essential aspect: the watch glass. This component, which protects the face of your watch, is much more than a simple shield against the elements; it is one of the components most exposed to shocks and hazards of daily life.

In this article, we’ll look at the different types of glass—from acrylic to the prestigious sapphire crystal—and reveal their secrets. Whether you’re a watch enthusiast, a discerning collector, or simply looking for your next watch, understanding what’s behind the glass of your watch can transform your experience and appreciation of it.

1. Acrylic Glass: The Entry Level

Acrylic glass, often used in budget watches , is a type of clear, lightweight plastic, often known as Plexiglas , Lucite , or Perspex . It is valued for its light weight and impact resistance but is generally the most prone to scratches.

It is particularly appreciated in vintage watches and models focused on value for money but also for its ease of restoration: scratches on acrylic glass can be relatively easily polished and removed. With special polishing agents, scratched acrylic glass can often be restored to its new appearance, an option that is not possible with mineral or sapphire glasses.

Brands like Timex often use this type of glass in their classic models, offering an affordable option without compromising functionality.

Example : Omega Speedmaster Professional watches, used by astronauts during the Apollo missions, were fitted with Hesalite glass, which is an acrylic glass.

2. Mineral Glass: The Compromise

Mineral glass is produced by treating ordinary glass with heat or chemical treatments to improve its strength. This process makes the glass harder and therefore more durable.

A natural evolution, mineral glass is a step up from acrylic. More scratch-resistant while remaining economical, it is a popular choice for mid-range watches. It offers an interesting compromise between durability and cost, positioning itself between acrylic glass and sapphire crystal in terms of quality and price.

Example : Many models in the Casio , G-Shock , Citizen Eco-Drive or Promaster ranges use mineral lenses.

3. Hardlex: The Seiko Signature

Hardlex glass is a specific creation of the Seiko brand, representing a significant improvement over standard mineral glass. Developed in-house by Seiko, Hardlex is distinguished by its greater resistance to scratches and shocks. This characteristic makes it particularly suitable for watches intended for use in difficult conditions, such as diving watches or sports watches.

Seiko's Hardlex glass represents a successful balance between quality and cost, offering increased strength without the premium price of sapphire, while outperforming standard mineral glass in terms of durability and impact resistance.

Example : Seiko's Hardlex glass is primarily used in their Prospex, Presage, Seiko 5 and Seiko 5 Sports lines.

4. Sapphire Glass: The Ultimate in Quality

Sapphire crystal, highly prized in high-end watches, is renowned for its exceptional scratch resistance, almost equivalent to that of diamonds, making it virtually immune to everyday scratches. Its remarkable transparency ensures perfect clarity for reading the time, often enhanced by anti-reflective treatments.

Although more expensive to produce, sapphire crystal is a preferred choice for luxury watches, highlighting a commitment to quality and elegance. Its durability is a major asset, although it is slightly more fragile to violent impacts compared to other types of glass. This combination of clarity, strength and aesthetics makes it a choice for those who prioritize finesse and longevity in their watches.

In some brands like Seiko , the same series can present models with sapphire crystals and others without, in order to bring a touch of luxury to certain variants. The SRPH49K1 is equipped with it while the SRPH93J1 or SRPH87K1 is equipped with a Hardlex crystal.

Example : Rolex , Patek Philippe and Audemars Piguet , known for their exquisite craftsmanship, choose sapphire crystal for the majority of their watches.

Conclusion

In conclusion, watch glass is an element that deserves our full attention. From affordable yet practical acrylic to durable and luxurious sapphire, each type has its place in the world of watchmaking. At PSB WATCHES, we highlight this diversity and are committed to offering you a range of choices that not only meet your functional needs but also your aesthetic tastes. Whether your next watch is an investment or a favorite, you will undoubtedly find your ideal on our site.

Casio LTP-V007L-7B1 with mineral glass, which equips the entire LTP-V007 series.