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How to choose a crystal for your watch

GMT Classics
There are currently three types of crystal available on the market: acrylic (plexiglass), mineral and sapphire.
All of them are designed to protect your watch face from external adversities, such as dust, humidity and shock.
Yet there is a considerable difference in how each type of crystal addresses these issues: the choice of the correct type for every watch is very specific and depends on many factors.
Besides, crystals can either bring out the best in your watch or completely destroy its appearance.

Let us consider each type of crystal by its own merit:

Acrylic (or Plexiglass).

These crystals are made of transparent thermoplastic and they are very economical.
Their flexibility allows manufacturers to bring them to different shapes with relative simplicity.
They scratch easily but the scratches can be easily removed by polishing the surface of the crystal.
They are very difficult to break or shatter.
With time these crystals lose a degree of transparency and suffer reduction in clarity. For that reason are usually used in cheaper models of watches.

Acrylic as a material was created in 1843 and is strong, tough and lightweight. Compared to glass it has a lower density but a higher impact strength. Acrylic has been used in aircraft manufacturing and up to date is still an important material across many industries, including the police sector.

Wrist watches with acrylic crystals can be advised to people who lead an active life style. They are good for sport, travel and camping.

Mineral

Mineral crystals represent the most popular and widely used type of watch crystals. To imagine what is the essence of the mineral, think of a glass window.

These crystals are harder to scratch than acrylic and they do not lose transparency over a period of time.

They look more "upmarket" and are used in more expensive watches.

You do have to take more care over mineral crystals as they break easier than acrylic. I sell hardened mineral crystals that are less likely to break.

The oldest piece of glass that was discovered by archaeologists stretches back to the year 35 BC. However, the earliest description of its manufacturing process dates back to the year 650 BC.

In any case, ever since the first watch was made and up until the discovery of Acrylic the face of every timepiece was covered by a mineral crystal. At present 90% of all watches are made with mineral crystal.

So, if you want to be traditional — mineral crystals are for you.

Sapphire

The sapphire crystal is nothing but synthetically produced crystalline aluminium oxide.The creation of synthetic sapphire, which is used in some more expensive watches is attributed to Parisian chemist Auguste Verneuil who was the first to discover a successful method of manufacturing synthetic gemstones. The Verneuil process is still widely used in the modern industrial crystal growth technology.

Its principal characteristic is its hardness, which is 9 on the Mohs Scale of hardness. Only diamond is harder (10). That makes sapphire highly resistant to scratches. However, it is precisely this feature that makes it brittle. It shatters much easier than acrylic or mineral crystals.

Due to the complexity of the manufacturing technology these crystals are very expensive. They are normally used in premium and luxury models of timepieces. The first sapphire watches appeared in the 1960s.

It is virtually impossible to see the difference between a mineral and sapphire crystal with the naked eye. They look almost identical. However, if you hold both crystals in your hands for several seconds you will feel that sapphire warms up slower. If you touch both crystals with the tip of your nose, you will feel that sapphire is considerably colder than mineral.

Sapphire is trendy and deluxe. It is very expensive and will give your watch face a shine and clarity for many years to come.

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