The watch crystal is one of the most important, yet overlooked components of a time piece. We’re breaking down everything you need to know about this watch part, including:
- What is the watch crystal?
- The 4 main types of watch crystals
- Choosing the best crystal for your watch
- How to keep your watch crystal in top shape
What is a Watch Crystal?
A watch crystal is the clear covering that sits over the watch face. It houses the watch hands and usually, the edges are covered by the bezel.
The crystal will more often than not fit inside the watch case, although this doesn’t mean that the case or bezel is holding down the crystal.
What’s important about the watch crystal is it’s a hard surface that is fairly resistant to scratches. However it can scratch, chip and get scuffed over time.
Also, it is important that the crystal is secure because it protects the face of the watch from water and dirt and other environmental influences that your watch can come in contact with.
4 Different Types of Watch Crystals
They type of crystal you need will depend on several factors– price, wearability, ease of repair, and scratch resistance.
We’ll discuss the four main types of watch crystals below.
1. Synthetic Sapphire
This transparent, lab grown element has exactly the same chemical composition as natural sapphire. Sapphire ranks a 9 on Mohs’ hardness scale. It is the most expensive type of crystal and the majority of watches imported from Switzerland contain them.
Sapphire and mineral glass generally look the same.
Mineral crystals are made of glass. This type of crystal ranks a 7 on the Mohs scale of hardness. They are inexpensive compared to sapphire crystals, usually costing less than one hundred dollars to replace if damaged.
Mineral glass crystals are sold in thicknesses of 1.00 mm, 1.5 mm, 2.0 mm, 2.5 mm and 3.0 mm.
Acrylic (aka plastic) is the most affordable type of crystal. It can be easily polished to remove light scuffs.
Modern pocket watches are usually fitted with plastic crystals. Most pocket watches use a low dome crystal, while wrist watches use a high dome crystal.
4. Anti-Reflective or Anti-Glare
This type of crystal has been coated on one or both sides with a substance – the same one used on anti-reflective eyeglasses – that lessens reflections and glare and makes it easier to read the watch face. Anti-reflective crystals can be made of either mineral glass or synthetic sapphire.
Viewed from the front, they are virtually invisible because they aren’t reflecting any light. In some instances, the coating gives the crystal a telltale bluish tint, as it does on eyeglasses. This tint is easiest to see if the watch has a light-colored dial.
How to Care for Your Watch Crystal
Mineral glass crystals should be kept away from items like keys, coins, tools, along with anything else that might scratch it. Crystals made of mineral glass are more likely to scratch than sapphire crystals.
But even synthetic sapphire crystal can be scratched. Materials with a higher score than “9” on the Mohs hardness scale can scratch sapphire.
Diamonds are graded “10” on the Mohs scale, so use extra caution with diamond jewelry around your sapphire crystal.
Minor scratches in a watch’s crystal can be refinished back to its original condition. Deeper scratches may need a full replacement. Be sure and take watches to a reputable watch repair center.
Other Watch Crystal Facts
Want more facts on your watch’s crystal? See below for a few more points of interest:
- Rolex Crystals need to be fitted by Case number. This number can be found, between the lugs at the 12 o’clock position.
- Omega Watches that are fitted for crystals require their case number located on the inside of the case back.
- The watch crystal can be installed either with a crystal life or glued in.
- To fit a watch crystal with a bezel with a crystal life, the crystal will need to be the next size up or in this example 22.3 so it will be 1/10th larger.
- If the watch crystal is glued in it will require the crystal to be the same size as the measurement or a tenth of a millimeter smaller.
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