It is not irrelevant what materials are used to produce watches. This applies to all parts of the watch, both case, bracelet, crown, buttons, dial, movement and of course, the crystal.
To make no mistake, the ‘crystal’ we are referring to here, is the transparent cover protecting the watch face and not the quartz crystal that serves as an oscillator in quartz watches.
Why Does the Crystal Material Matter?
Materials matter in watchmaking. The choice of materials to produce a watch is crucial in terms of durability, aesthetics and hypoallergenic properties.
But why does it matter which type of material the crystal is made of?
Here are some key questions:
- How strong is the crystal and how easy does it shatter?
- How easy does the crystal pick up scratches?
- How easy can scratches be polished out once the damage has occurred?
- How does the light reflect?
- What’s the cost?
What Is the Best Watch Crystal?
There are basically three glass type materials commonly used for crystals in watchmaking and they are all justified for their own reasons, so let’s go through the pros and cons for all of them.
Hesalite is also known as plexiglass or acrylic glass, it’s inexpensive and it doesn’t shatter as easy as other materials.
Another important property of hesalite has to do with scratches, probably enemy no. 1 for any owner of a brand new wristwatch.
Hesalite will pick up scratches a little easier than sapphire, but the good news is that once the damage is done, acrylic crystal can be easily polished, leaving your watch face as clear as ever.
The original Omega Speedmaster ‘Moonwatch’ was offered with Hesalite crystal and that was one of the reasons why NASA selected this watch for the Apollo 11 astronauts.
When hesalite glass breaks, it cracks rather than shatter and NASA saw this as an important property to avoid glass pieces from flying around should the crystal break.
Many Rolex Sports models as well as outdoor- and military watches use acrylic crystal.
Mineral is a quite popular crystal material for mid-tier watches and for good reason. Mineral shares a lot of properties with those at the top of the market, but is cheaper.
It’s made of regular glass crystals treated with heat or chemicals to make them tougher in order to withstand scratches.
The material is 7 times harder than acrylic crystal and it also withstands scratches better.
Mineral doesn’t crack or shatter easily, but if you should be unlucky, a replacement would be quite affordable.
Sapphire is generally to be considered the best of the best concerning crystal material.
Sapphire crystals are usually a synthetic compound rather than formed from a natural sapphire, but they do share the same properties.
Sapphire crystals are 3 times harder than mineral crystals, extremely scratch-resistant and the hardest mineral after diamond, but it’s also the most expensive crystal type on the market.
In fact a sapphire crystal is so hard only another sapphire or diamond would be able to leave scratches.
No surprise this is the preferred material for crystals in most luxury watches.
Sapphire crystals may be the best for many watch types, but a replacement would be more costly than a mineral crystal replacement.
Due to the sovereign properties of sapphire, breakages are much more unlikely to happen though.