What Are Jewels in Watches and Why Do They Matter?

When you begin exploring the world of horology, you will likely encounter technical specifications that mention a "jewel count." For many new collectors, this raises an interesting question: What are jewels in watches, and do they make a timepiece more valuable?

It is a common misconception that these jewels are decorative gemstones designed to make the watch look expensive. In reality, jewels in watch movements serve a much more practical, engineering-focused purpose. They are the unsung heroes of precision, ensuring that your watch runs smoothly for decades rather than breaking down within a few months.

In this comprehensive guide, we will dive deep into the world of watch jewels meaning, how they function, and why they are essential for high-end watch movements.

1. What Are Jewels in Watches?

To put it simply, what are jewels in watches? They are tiny, synthetic gemstones—usually rubies or sapphires—that act as bearings for the moving parts within a mechanical watch.

In any mechanical machine, moving parts create friction. In a watch, the gears (called wheels) are mounted on axles (pivots). These pivots spin thousands of times a day. If a steel pivot were to spin inside a hole drilled directly into a brass or steel plate, the metal-on-metal contact would eventually grind the parts down, creating "metal dust" and causing the watch to lose accuracy or stop altogether.

The Role of Synthetic Stones

Modern watchmakers use sapphire jewels in watches or synthetic rubies because these materials are incredibly hard. On the Mohs scale of mineral hardness, diamonds are a 10, while synthetic rubies and sapphires are a 9. This hardness makes them nearly impossible to wear down.

By placing these hard stones at the points of highest friction, watchmakers ensure that the steel pivots can rotate with minimal resistance. This is the fundamental answer to "what are jewels in watches": they are high-performance bearings designed to eliminate wear and tear.

Alt-text: Watch movement with jewels

2. Why Jewels Are Used in Watches

Understanding the functions of jewels in watches helps you appreciate the craftsmanship behind a luxury timepiece. There are three primary reasons why these stones are used:

Reducing Friction

Friction is the enemy of any mechanical device. In a watch, even a tiny amount of resistance can slow down the movement. Jewels have a naturally slick surface. When a polished steel pivot rotates against a polished jewel, the friction is significantly lower than if it were rotating against another metal.

Improving Accuracy

When friction is minimized, the energy from the mainspring can flow through the gear train more consistently. This is how jewels affect watch accuracy. If the friction levels fluctuated, the watch would speed up or slow down unpredictably. Jewels provide a stable environment for consistent timekeeping.

Increasing Durability

Metal-on-metal contact leads to "pitting" and deformation over time. Because jewels are so hard, they do not deform. A well-jeweled movement can last for over a hundred years with proper servicing, whereas a non-jeweled movement would likely grind itself to a halt in a matter of years.

3. The Different Watch Jewel Components

When we talk about what are jewels in watches, it is helpful to know that not all jewels look or act the same. There are several specific types of watch jewel components used in a standard movement:

1. Hole Jewels: These are the most common. They are donut-shaped stones pressed into the plates of the movement. The pivot of a gear fits into the hole in the center.

2. Cap Jewels: These sit on top of the hole jewels. They act as a "ceiling" to prevent the pivot from moving up and down too much. They also help hold the lubricating oil in place through capillary action.

3. Pallet Jewels: These are rectangular stones found on the pallet fork. They are responsible for stopping and releasing the escape wheel, which creates the "tick-tock" sound.

4. Impulse Jewels (Roller Jewels): This is a single, D-shaped stone that sits on the balance wheel and interacts with the pallet fork to keep the watch swinging.

4. How Jewels Affect the Watch’s Performance

The presence of jewels is a hallmark of luxury watch mechanisms. Without them, the high-frequency vibrations required for modern precision would be impossible to maintain.

Increased Efficiency

A watch movement has a limited amount of energy stored in its mainspring. If that energy is "eaten up" by friction in the gear train, the watch will have a shorter power reserve. By using jewels in watch movements, engineers ensure that as much energy as possible reaches the balance wheel, allowing the watch to run longer on a single wind.

Longevity and Maintenance

While the oil in a watch can eventually dry out, the jewels themselves remain intact. During a professional service, a watchmaker simply cleans the jewels and applies fresh oil. If the watch relied on metal bushings, the watchmaker would have to replace the entire plate or re-drill the holes—a much more invasive and expensive process.

5. What is the Ideal Jewel Count in Watches?

You may see numbers like "17 Jewels," "21 Jewels," or "31 Jewels" engraved on a watch case or movement. But what does this jewel count in watches actually mean for the buyer?

• 17 Jewels (Fully Jeweled): This is generally considered the standard for a high-quality manual-wind watch. It covers all the essential pivot points from the center wheel to the balance staff.

• 21–25 Jewels: This is common in automatic (self-winding) watches. The extra jewels are used in the winding mechanism (the rotor and its reduction gears) to handle the constant motion of the weight as you move your arm.

• 27–30+ Jewels: These counts are usually found in high-end watch movements with "complications." If a watch has a chronograph (stopwatch), a perpetual calendar, or a minute repeater, it requires more moving parts, and therefore, more jewels to protect those parts.

Note: Beware of "jewel inflation" in vintage, low-quality watches. Some manufacturers in the mid-20th century added "non-functional" jewels to watches simply to claim a higher count for marketing purposes. In modern luxury watch collections, every jewel listed is functional.

6. Watch Jewels vs. Ball Bearings

In modern horology, there is an ongoing debate: watch jewels vs ball bearings.

While jewels are perfect for small, fast-spinning pivots, they aren't always the best choice for heavy, rotating parts. For example, the "rotor" (the weight that winds an automatic watch is relatively heavy. Many modern brands, like Omega or Rolex, use tiny ceramic or stainless steel ball bearings for the rotor instead of a single jewel.

Ball bearings can handle the lateral stress of a heavy weight better than a jewel can. However, for the delicate internal gears, jewels remain the gold standard.

7. Does a Higher Jewel Count Mean Better Quality?

When asking what are jewels in watches, it is natural to assume that "more is better." However, this isn't always the case.

A 17-jewel hand-wound movement from a prestigious brand can be significantly higher in quality than a 30-jewel mass-produced automatic movement. The quality of a watch is determined by:

• The precision of the parts.

• The finishing of the surfaces.

• The regulation and adjustment of the movement.

A high jewel count is a sign of complexity, but not necessarily superiority. That said, most high-end watch movements naturally have higher jewel counts because they are complex and require more protection.

8. Sapphire vs. Ruby: Which is Better?

While the term "jewels" sounds fancy, most people are surprised to learn they are synthetic. Natural rubies were used in the 1700s and 1800s, but they were often inconsistent in clarity and hardness.

Today, sapphire jewels in watches and synthetic rubies are created in labs using the Verneuil process (flame fusion). These lab-grown stones are:

• Perfectly uniform.

• Free of internal flaws.

• Cheaper to produce than mining natural stones.

• Precisely cut using lasers or diamond tools.

Whether the jewel is red (ruby) or clear/blue (sapphire) doesn't significantly change the performance. The color is often chosen based on the aesthetic tradition of the watchmaker.

Alt-text: Watch components with jewels

9. Common Questions About Watch Jewels

Can jewels break?

It is very rare, but a jewel can crack if the watch suffers a severe impact (like being dropped on a concrete floor). This is why many luxury watches use "Incabloc" or other shock protection systems. These systems use tiny springs to allow the jewels to "bounce" slightly, absorbing the energy of an impact.

Do quartz watches have jewels?

Yes! While cheap quartz watches might have zero jewels because they have very few moving parts, high-end quartz movements (like those from Grand Seiko) often contain 7 to 9 jewels to ensure the gear train that moves the hands lasts a lifetime.

Why are they called jewels?

The name is a holdover from the early days of watchmaking when actual precious stones were used. Even though they are now synthetic, the industry keeps the name "jewels" to honor the history of the craft.

10. The Evolution of Jewels in Watchmaking

To truly understand what are jewels in watches, we must look at how far they’ve come. Before 1704, watches relied on metal bushings. A gentleman named Nicolas Fatio de Duillier patented the idea of using pierced gemstones as bearings. This revolutionized the industry, allowing for much thinner and more accurate pocket watches.

Today, we take these components for granted, but they are the reason a mechanical watch can tick 28,800 times per hour, every hour, for years without failing.

Conclusion

So, what are jewels in watches? They are the silent guardians of your watch’s movement. By reducing friction, protecting against wear, and ensuring consistent accuracy, they allow mechanical watches to transcend being mere tools and become heirloom-quality pieces of art.

Whether you are looking at a 17-jewel vintage piece or a 40-jewel modern masterpiece, the jewels in watch movements represent a commitment to longevity and precision engineering. The next time you see "25 Jewels" engraved on the back of a watch, you’ll know that it isn't just a marketing gimmick—it’s a sign of a movement built to stand the test of time. At Watch Pilot, we help you understand these intricate details and provide timepieces that embody both craftsmanship and durability.