What Are The Jewels in a Watch For?
Read our eye-opening look at mechanical watches and allow us to explain what the jewels in watches are for and how watchmakers use jewels in the mysterious and centuries-old craft of watchmaking.
Ever ask yourself
"What are the jewels in a watch for?"
Mechanical watches use spring-wound movements and therefore don't require a battery. So what are watch jewels and exactly what do jewels do in a watch? Like any mechanical device, there are gears that need to move or rotate. Watches are no different and also use bearings and these bearings that are found in the higher end mechanical watches are made out of jewels. Jewels in watches are smooth and don't allow much friction and are therefore watch jewels are used in order to make the movement of these gears easier.
So yes, there are actual jewels in the movement of your watch and usually quite a few of them!
Back in the day, watchmakers used natural genuine rubies to create these bearings and more recently, they adopted the use of lab-created rubies (also known as synthetic rubies). The purpose of these jewels is to act as bearings to various components in the watch specifically the parts that would normally wear down easily such as the escape lever and the impulse jewel.
Before the 70's, when battery powered (quartz) watches were introduced, all watches were mechanical and used about five to seven jewels in the watch's caliber.
Watchmakers use a few types of jewels:
- Hole Jewels:
- A hole jewel (also known as a pierced jewel) is a type of jewel with a hole bored into it so that it can be mounted on the wheel's axle or pivots such as a cylindrical pivot or a conical pivot.
It usually has a slightly rounded top or with a flat bottom. Together with a cap jewel (see below) they create a set called a pivot bearing. When used in conjunction, they allow an axle to spin and when used on the balance staff they have an anti-shock assembly which has springs holding them in place for shock absorption.
- Cap Jewels:
- A cap jewel is a type of jewel without a hole bored into it which is used to minimize the balance staff's movement. Cap jewels usually are used in conjunction with a pivot jewel and have a type of shock protection in place such as a spring at each end. This protects the watch in the event that the watch is dropped or gets hit by something while being worn.
- Pallet Jewels:
- A pallet jewel is usually a rectangularly shaped jewel used at the end of each arm on the pallet fork.
- Roller Jewels:
- A roller jewel is a type of jewel that is used a connection point between the escape wheel and the pallets and sits inside the pallet fork.
Most mechanical watches have around 17 jewels that are used in several areas:
- Balance Wheel
- One impulse jewel can be found in the Balance wheel assembly where the escapement level hits it.
- Staff Pivot
- Two pairs of jewels (a hole jewel and a cap jewel x 2) are used as pivot bearings on staff pivot.
- Center Wheel
- Two jewels (a hole jewel and a cap jewel) are used as a pivot bearing for the center wheel.
- Escape Lever Pallet
- Two pallet jewels are used in the escape lever pallet.
- Escape Lever
- Two jewels (a hole jewel and a cap jewel) are used as a pivot bearing in the escape lever.
- Fourth Wheel
- Two jewels (a hole jewel and a cap jewel) are used as a pivot bearing in the 4th wheel.
- Third Wheel
- Two jewels (a hole jewel and a cap jewel) are used as a pivot bearing in the 3rd wheel.
- Escape Wheel
- Two jewels (a hole jewel and a cap jewel) are used as a pivot bearing in the escape wheel.
Around 17 jewels are used on a standard mechanical jewel watch without any high-complications. If the watch has high-complications such as a perpetual calendar watch, a chronograph (a watch with a stopwatch function) or a tourbillon watch will use more jewels.
Although the most jewels in a watch ever may be hard to track, oftentimes super-high complications watches have an unfathomable amount of jewels in the movement. An interesting read may be our article on the World's most complicated watch which had 242 jewels in the movement. Typically, the more complications are on the watch the more jewels you can expect in the watch's movement since more bearings are needed to reduce friction between the many components needed to create said complications.
To learn more about watch terminology, please visit our watch terminology page which is the world's leading dictionary for understanding about watch terms and complications.