Fancy or Functional: Why do Watch Movements Have Jewels?

A watch movement is built from many different parts such as a balance spring, movement plate, bridges, and jewels. Many people wonder what jewels do, and if they are even necessary. 

For over a century, Seiko has been making some of the most innovative movements in the history of the watchmaking world. Seiko’s 7S movement line, such as the famed 7S26, has always been an affordable workhorse that powered the iconic SKX divers. 


Source: Caliber Corner


Of all the watch mod parts there are, one could argue that a Seiko movement is the most important. 

Not only that, but also Seiko movements like the Seiko calibres 6R15, 4R35, 4R36, NH35, and NH36 offer great value. The NH series are often the popular choice for Seiko mods, as they are affordable, and work for years to come. One thing that all these famous workhorse movements have in common is the presence of jewels in its myriad parts.

Do you ever ask yourself what the jewels in a Seiko watch movement do?



Unlike gem-setting on dials, bezels, or cases, jewels used in movements are important parts of the movement helping with accuracy and longevity. In other words, while gem settings are added for aesthetic reasons or to add value, watch jewels serve a functional purpose for a timepiece’s movement.

Although serious watch collectors check how many jewels a movement has before making a purchase, some simply don’t pay attention to this detail. Watch jewels are indispensable for mechanical movements, and watchmaking would not be the same without jewels. 

Keep reading to learn why!


History of Watch Jewels

Today, jewels or jewel bearings are synthetic rubies or sapphires that are set into different parts of the watch movement. They are used to help reduce friction in moving parts. The gems are designed to provide a hard surface that allows the metal components to move freely. 

To do this, these jewels are placed around pivots, gears, and pinions for low friction connections. In fact, having higher friction within the movement can not only cause variations in timekeeping but also add to premature wear, corrosion, and create the need for more frequent servicing.

Jewel bearings were first developed in the early 1700s by the Swiss inventor Nicolas Fatio de Duilier and the brothers, Peter and Jacob Debaufre.

The original jewels were made of diamonds, rubies, or sapphires. However, the use of natural gemstones added to the cost and exclusivity of timepieces during this period. Today watchmakers use synthetic sapphires and rubies to help lower the cost.


Types of Watch Jewels

Source: Precision Watches


You may think that jewels are one-type-fits-all, but they are more complicated than that. Four different types of bearing can be found in modern day watch movements.

Hole Jewels

Hole jewels, also known as pierced jewels, can easily be spotted due to the hole in the stone.This hole is placed to allow mounting right on a wheel’s axle or pivots, whether cylindrical or conical. Hole jewels often have a slightly rounded top side and their bottom part is flat.

If paired with a cap jewel, they make up a set referred to as a pivot bearing making the axle spin. Otherwise, when placed on the balance staff, they make an anti-shock part and are held in place by springs for optimal shock absorption.


Source: Precision Watches


Cap Jewels

Although cap jewels or also known as end stones or capstones work just as the others do, they require a second or outer jewel that sits at the tip of the gear shaft. This ensures lubrication for fast-moving parts like the balance wheel as it forms a small oil reservoir between the two jewels. 

Not only that, but this type of bearing also keeps the shoulders of the arbor from rubbing against the jewels through the conical shape of the shaft due to the jewel’s formation.

Pallet Jewels

Source: Luxuo


The pallet jewels are rectangular jewels and have a pretty straightforward function. These jewels transfer power in the movement. They also can be found at the end of each of the arms of a pallet fork.

Roller Jewels

A roller wheel is to connect the escape wheel and the pallets in a watch’s movement so it serves as a conjunction point between the two. Roller jewels are usually found inside the pallet fork of a movement with a caved upper side while its lower side is flat.


Most modern watch movements have 17 jewels or 21 jewels, which don’t differ much from the settings of a 17-jewel movement. You might be wondering if having more watch jewels means the watch is better quality than other wristwatches?

Well, don’t just look at high-end or luxury watch brands such as Patek Philippe, Rolex, or Omega as you can find a lot of complicated watches in the mid-tier and even entry-level arena.

You must keep in mind that watch jewels aren’t just accessories, they serve actual functions, just as any part of a watch does. Their aforementioned function is to minimize the friction between the mechanical parts of a watch. 


Source: Satya Rasyid Triabadi on YT


This protects the movement’s components and helps it last longer, keeping it from getting worn out easily. Given this, the number of jewels doesn’t necessarily indicate that its movement is a lot better than the others but shows how complicated or well engineered a mechanical movement could be in some cases.

Some designs need less jewels, and others need more. For a three hand watch, having more than 21 jewels is pushing it, and we have to wonder why the movement needs so many!


Adding Function to Your Watch

Seiko mod watches have gained a lot of popularity over the years, and namokiMODS is one of the go-to online stores for SKX007 parts for enthusiasts who love to customize their watches. If you are one of these enthusiasts, then you probably know how much fun it is to create unique designs that stand out. 

At namokiMODS, you will find a wide range of parts to choose from to build the perfect watch for your style. Whether it is a new bezel, dial, chapter ring, or any other component, namokiMODS offers it all. Our online store has an extensive collection of high-quality parts that are compatible with Seiko watches. They also offer aftermarket parts that are designed to fit perfectly and enhance the aesthetics of the watch.

If it has been a while since you visited our store, it is time to take a look at our new releases as we have just added new bezel inserts, stylish watch hands, and parts for the NH34!

March 11, 2023 — Jeremiah A

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