Every watch as some sort of transparent covering that protects the dial or digital display underneath. Sometimes referred to as the crystal, this component is also described as the watch glass. There are three different types of watch glass used in the manufacture of nearly every watch on the market. These will be discussed in this guide. Note that some manufacturers have developed their own proprietary watch glass materials. However, they are so brand specific and rare that they will not be discussed in this guide. Needless to say that any modern watch is more likely than not to feature a glass made of acrylic, mineral or sapphire.
Acrylic watch glass is made from a plastic, or polymer, made from acrylate. The plastic is both soft and pliable but still relatively durable. That is what makes it an excellent choice for watch crystals. Its soft and pliable nature allows watchmakers to form it in nearly any shape. Yet the plastic is durable enough to stand up to a significant impact. Popular brands like swatch and flick flak use acrylic glass in their watches.
Watchmakers appreciate acrylic because it is affordable. It can be mass-produced relatively cheaply, thereby not adding significant costs to the watchmaking process. You will find acrylic glass on many low-end and entry-level watches. Acrylic is used less often in manufacturing luxury brands.
In terms of being workable, acrylic can be formed into a variety of shapes. For example, you might have a watch with a domed glass. It is probably acrylic. Creating a dome shape with mineral or sapphire is nearly impossible without spending a fortune. On the other hand, acrylic can be easily formed into a domed crystal without increasing cost. Plastic is a popular choice for watch material and more accurately referred to as Silicon.
Mineral glass is the mid-range product for watch crystals. It costs more than acrylic but not as much as sapphire. For comparative purposes, mineral glass is the same kind of class you probably have in the windows in your home. It is a silica product that offers decent scratch resistance and moderate durability.
Watches in the mid-level price range tend to feature mineral glass. It doesn't look as cheap, for starters. Moreover, it can be hard to tell the difference between a good piece of mineral glass and a piece of sapphire with the naked eye.
Sapphire is considered the premium material for manufacturing watch crystals. As such, it is also the most expensive. Only your higher-priced watches tend to feature it.
The thing to understand about sapphire glass is that it is man-made. Watchmakers do not use natural sapphire; it is too expensive and difficult to work with. Synthetic sapphire, also known as corundum, is made in a laboratory using a process first developed in the early 1900s. The process creates one of the hardest oxide crystals known to man.
Extreme Scratch Resistance – Being such a hard oxide crystal, sapphire glass is extremely difficult to scratch. You can do it, but it takes an awful lot of effort. It has been suggested that the only thing capable of causing a deep scratch in sapphire is diamond. This makes it an excellent choice for hard-wearing watches for military and luxury watches.
Excellent Impact Resistance – The material's hardness also makes it especially resistant to impact. Under normal circumstances, a typical impact will not bother a sapphire crystal. Saphire will often be combined with a Titanium or other hard-wearing metal like stainless steel strap and body of the watch.
Pleasing Aesthetic – Sapphire's nature as an oxide crystal dictates that it has a very pleasing aesthetic. Kept clean, a sapphire crystal looks stunning. It offers considerably more clarity compared to acrylic. Better yet, it does not get cloudy.
Choosing a watch glass material really comes down to personal preference. If budget is your primary concern, acrylic is your best bet. You might also prefer acrylic if you subject your watches to extreme punishment. There is no point in damaging a higher-priced watch even if the crystal is better.
In terms of impacts and scratches, ask yourself how frequently your watch comes into contact with other surfaces. If you live and work in a low-impact environment, for example, spending a little more on a mineral or sapphire model might be worth your while. In the end, it boils down to whatever makes the most sense based on your budget and normal use.