The watch glass is one of the most important — and most often overlooked — elements when purchasing a timepiece. It protects the dial, determines readability, and directly influences the durability of your watch. There are three main types: sapphire, mineral, and acrylic. Overview.
Acrylic glass (or plexiglass)
Acrylic glass is the oldest and least expensive of the three. Used on vintage watches and entry-level models, it offers several advantages:
- Lightweight and flexible (it does not break easily upon impact)
- Easy to polish : superficial scratches can be removed
- Inexpensive to replace
However, its drawbacks are significant: it scratches very easily and yellows over time. It is rarely found on contemporary quality Swiss watches.
Mineral glass
Mineral glass is tempered glass, thermally treated to enhance its resistance. It is the standard for the mid-range market:
- More scratch-resistant than acrylic
- Good transparency and clean visual appearance
- Intermediate price
However, it remains sensitive to strong impacts (it can crack) and scratches more easily than sapphire. An acceptable compromise, but not ideal for a watch intended to last.
Sapphire glass: the luxury standard
Sapphire glass is made from synthetic corundum — the same material as natural sapphire. With a hardness of 9 on the Mohs scale (diamond is 10), it is the most scratch-resistant glass available.
Its advantages are numerous:
- Almost scratch-resistant under normal conditions of use
- Anti-reflective treatment possible (application of anti-UV coatings) for optimal readability
- Exceptional transparency: the dial appears clear and bright
- Almost unlimited lifespan: it does not age
Its only drawback: in the event of a very strong impact, it can break cleanly (without cracking). But in normal daily use, it is the uncompromising choice.
Comparison Table
| Criterion | Acrylic | Mineral | Sapphire |
|---|---|---|---|
| Scratch resistance | Low | Medium | Excellent |
| Shock resistance | Good | Medium | Good |
| Transparency | Medium | Good | Excellent |
| Lifespan | Limited | Medium | Very long |
| Cost | Low | Medium | High |
The MSW choice: anti-reflective sapphire
All MSW My Swiss Watch watches are equipped with sapphire glass with anti-reflective coating . This choice is not insignificant: it ensures that your watch will remain as beautiful in 20 years as on the first day, without scratches or visual degradation.
Combined with the VALJOUX 7750 movement and the lifetime warranty, the sapphire crystal is one of the non-negotiable quality standards at MSW.
Conclusion
If you are investing in a quality Swiss watch, sapphire crystal is essential. It is the only option that guarantees lasting protection for your dial and optimal readability in all circumstances. Do not cut corners on this point.
Discover the MSW My Swiss Watch watches — all equipped with anti-reflective sapphire crystal.