Jewels in Watches

The mechanics of a watch are pretty simple. When a watch operates, the entire intricate system of gears and wheels gets into action. A watch works on these gears and their movement, these gears need to be protected against the very obvious wear and tear. To create this protection, watchmakers started adding jewels in-between the gears and wheels of the watches they make. Thanks to their smooth surfaces, these jewels reduce friction and help in shock absorption.

It might be surprising that various minerals used as jewels in the watches include sapphire, ruby (synthetic), diamonds, and more. These minerals are harder than the metal used in the watch gears. Thus, there is not much wear when the gears push on these jewels.

The number of jewels used varies from watch to watch. So, does that mean that your watch is super expensive because there are more jewels in it? The answer is No. Why, you ask? Read this article till the end to find out. 

The History Of Jewels In Watches

Jewels have been placed in watches since the early 1700s. In 1704, Nicolas Fatio de Duillier, Jacob Debaufre, and Peter Debaufre invented jewel bearings and filed an English Patent for this concept. They used original minerals like diamonds, garnet, ruby, and sapphire to prevent the wear but could not go forward with the same minerals due to their expensive and rare availability.

It wasn’t until the 1930s that the jewels were made by rubbing the hard minerals onto brass settings. This method took a lot of time and effort. Also, the jewel pivots were made using diamond abrasives and couldn’t be replaced easily. 

Since 1902, synthetic sapphire and ruby minerals have been used as watch jewels. They are easy to obtain, slicker, and harder than any other metal. They can also protect the watch gears from getting worn out, even under heavy pressure. These synthetic jewels are made using high powered laser precision, advanced chemical etching, and ultrasonic milling.

Minerals That Are Used As Jewels And Their Properties

In today’s watch production, synthetic sapphire and synthetic ruby (AI203 corundum) are commonly used jewels. They are grown as cone-shaped chunks of materials or ‘boule.’ Synthetic jewels do not possess the impurities a natural jewel may possess. This helps in the smoother functioning of watches. Both synthetic ruby and sapphire have the same physical properties as they come from the same family of minerals. The only difference is their color.

Diamond, garnets, glass, and other minerals provide equal wear resistance but must be prepared heavily. Even slight surface irregularities can hinder the motions of the gears. Hence, these minerals have to be smoothened and set for longer. The minerals used must fall on the higher end of the Mohs scale of hardness. Although being at the top, the diamond requires heavy abrasion to be used as a jewel.

Types Of Jewel Bearings Used In Watches

The shapes of jewel bearings matter the most since they allow movement. For watches that work on mechanical movements like wound watches, the most common bearings are hole jewels and cap jewels. 

Hole Jewels

They are also known as ‘pierced jewels.’ They are single, concave jewels with a hole in the center. They look similar to a doughnut. These will be mounted onto a wheel’s axle or pivots. They can be mounted onto cylindrical or conical pivots. A hole jewel and a cap jewel make a ‘pivot bearing,’ allowing an axle to spin. They can also be used with a balance staff and springs to aid in shock absorption. Oil present around the hole aids in lubrication and smooth turning of the gears.

Cap Jewels

They are also known as end-stones or capstones. These jewels do not have any hole in them but have second, outer jewels placed at the tip of the gear shaft. Lubricant is present between the two jewels for fast movement. The cap jewels are built such that the lubricant oil is prevented from seeping down the arbor.

Cap jewels, along with pivot jewels, can be used to protect the watch by adding a spring on either side, so when your watch falls or hits something hard, the interior remains safe. 

Some other types of jewel bearings, based on their location:

• Brick-shaped pallet jewels: these jewels engage and release the escape wheels.
• Roller jewels: these are located on the balance wheels. They keep swinging back and forth for smooth continuous movement.

How Many Jewels in a Watch?

Basic mechanical watches have around 17 jewels in them. Automatic watches that have a self-winding mechanism usually have 25-57 jewels. Some watches with more complicated mechanisms have even more; though the higher jewel count does not specifically mean it is a higher quality watch.

Some watches also have 21 jewels to reduce positional errors. It is rare to see any watch with more than 21 jewels in them. The standard requirement is only 17, however, the modern self-winding watches do use 25 – 27 jewels.

If you're not sure of the number of jewels in your watch and it's not written anywhere, you should consult the manufacturer. The majority of automatic watches have the jewel count etched onto the rotor.

Click here to see my guide on How Tight Should a Watch be

Location Of Jewels In Watches

A typical gear train of a watch has four wheels. Different jewel bearings are located in different parts of the watch to aid in various functions. Most watches have 17 – 21 jewels that aid in the smooth functioning of the watch.

The first seven jewels are basic and needed for any mechanical watch. They are placed as follows:

• At the balance wheel --  four jewels. They include both hole jewels and cap jewels
• At the escape wheels -- one pallet jewel each.

Some additional jewels are located at:

• At the fast-moving parts of the gear system – eight-hole jewels
• On the center wheel – 2 to 4 jewels
• On escape wheels – 2 to 4 jewels
• On the pallet – 2 to 4 jewels

A 17 jeweled watch is typically referred to as a ‘fully jeweled watch,’ whereas a 21 jeweled watch means that the extra jewels were added to reduce positional errors further. Self-winding watches are usually made with more than 21 jewels.

Sometimes, more additional jewels may be required for:

• Automatic watches – to transfer the power generated by the wearer’s wrist to the gear system
• Chime watches
• Display watches that show the date, time, and other features
• Smartwatches
• Tourbillion watches

Do Quartz Watches Have Jewels In Them?

While Quartz watches are battery powered, they too have at least some amount of jewels in them. This is because, although they are battery-operated, the hands' movement of the watches is still delicate and needs care and attention. A typical jeweled quartz watch hosts anywhere between 5 and 10 jewels depending on the manufacturer and the design complications.

The Advantages Of Jewels In Watches

The fourth wheel of a watch alone takes around 1,440 complete rotations in one day and 525,600 full rotations a year. You can imagine how much wear it is susceptible to. We’ve given you the basic requirements of jewels in watches but let us also list out the advantages in a more elaborate manner:

• Avoids frequent replacement of gears as the jewels minimize wear and tear
• Enhances the smooth functioning of a watch due to constant and proper lubrication systems set in the jewels
• Minimizes the random errors in the watch’s second and minute hands’ functioning 
• Makes way for less friction due to the jewels’ low weight, small size, and smooth surface
• Delivers temperature stability as jewels will not randomly heat up due to the constant turning of gears.
• As jewel bearings are durable, your watch will function well for a more extended period
• Provides low kinetic friction while providing constant static friction for the watch to work well.
• The jewels mounted on springs produce an anti-shock system. This prevents the gear train from being affected if any pressure is applied to the outer surface of the watch.

Do More Jewels In A Watch Equal More Efficiency?

So, now back to the initial question. It has been an age-old myth that the more jewels you have in your watch, the more expensive and efficient it is. However, the answer simply is that you only need the required number of jewels your watch needs. The number of needed jewels varies based on a watch’s functions and features. 

A basic mechanical watch only needs 17 jewels. You can’t add more jewels to such a watch to make it more ‘efficient.’ All its functional requirements are already being met, and there are jewels already placed wherever needed. Watches with heavy functions do require more jewels, but that is only to aid in the given operations. Stopwatches show features like pulse, calories burnt, oxygen levels, and such. For these values to be sent to the gear train and displayed, you may require more jewels, but increasing the required number doesn’t change its efficiency by a lot. 

Is My Watch Worth More Money Due To The Jewels?

So, now back to the initial question. Generally, when people hear that their watch has jewels, they think they can sell it off to make the jewels worth it in cash. But, you need to keep in mind that these jewels are synthetic and man-made. They do not equal an original jewel’s worth.

Conclusion

Modern-day watches use synthetic, laboratory-processed jewels or gemstones as a part of the watch’s interior gear train. This facilitates smooth movement of gears, minimizes friction and wear of the wheels, and protects the gear systems from damage. There are different numbers, types, and placements of these jewels based on the desired functioning of a watch. Interesting, right?