Why Are There Jewels In Watches Purpose Function Explained

At first glance, the tiny red or clear dots embedded in a mechanical watch movement might look like decorative gemstones. But these aren’t for show—they’re functional components known as “jewels,” and they play a crucial role in the performance and durability of mechanical timepieces. Far from being mere luxury embellishments, watch jewels are precision-engineered elements that reduce friction, enhance accuracy, and protect delicate parts from wear. Understanding their purpose reveals why even modestly priced mechanical watches often feature them.

The True Purpose of Watch Jewels

Watch jewels are synthetic bearings made from materials like ruby (corundum) or sapphire, chosen for their extreme hardness and low friction coefficient. They are placed at key pivot points within the watch movement where metal-on-metal contact would otherwise occur. These points include the balance wheel, escapement, pallet fork, and gear train pivots—all areas subject to constant motion and stress.

Without jewels, the steel shafts (or pivots) of gears and levers would rub directly against the brass or steel plates of the movement. Over time, this friction leads to wear, increased energy loss, and reduced accuracy. By inserting a hard, smooth jewel bearing between these moving parts, manufacturers significantly reduce resistance and prolong the life of the mechanism.

Tip: A higher jewel count doesn’t always mean better quality—what matters is strategic placement in high-stress areas.

How Watch Jewels Reduce Friction and Wear

Friction is the enemy of precision in any mechanical system. In a typical mechanical watch, the balance wheel oscillates 6 to 10 times per second, meaning millions of movements each day. At such frequencies, even microscopic wear can accumulate rapidly without proper lubrication and protection.

Jewels act as low-friction pivot points. The hole in the center of each jewel is polished to an extremely fine finish, creating a nearly perfect surface for the steel pivot to rotate within. This minimizes energy loss and reduces the need for frequent servicing. Additionally, because synthetic rubies are harder than steel, they resist deformation and scoring far better than metal bushings ever could.

“Jewels aren’t about glamour—they’re about engineering efficiency. A well-jeweled movement runs smoother, lasts longer, and maintains accuracy over years.” — Daniel Moreau, Master Watchmaker and Horology Instructor

Types of Watch Jewels and Their Locations

Not all jewels serve the same function. They come in different forms depending on their position and mechanical requirement:

• Hole jewels: The most common type, used as bearings for rotating shafts. Installed in pairs (top and bottom) for stability.
• Cap jewels (or endstones): Flat jewels placed above or below hole jewels, especially in critical areas like the balance wheel. They prevent axial play and reduce lateral movement.
• Pallet jewels: Found in the escapement, these receive direct impact from the escape wheel teeth and must be exceptionally durable.
• Roller jewels: Small cylindrical jewels mounted on the balance roller, interacting with the pallet fork to regulate motion.

Type of Jewel	Function	Typical Location
Hole Jewel	Bearing for rotating pivot	Gear train, escapement, balance staff
Cap Jewel	Reduces end-shake and friction	Above/below balance wheel pivots
Pallet Jewel	Withstands repeated impacts	On pallet fork arms
Roller Jewel	Transfers impulse from fork to balance	Mounted on balance roller

Historical Evolution of Watch Jewels

The use of jewels in timepieces dates back to the early 18th century. In 1704, Nicolas Fatio de Duillier, along with Peter Debaufre and Jacob Debaufre, patented the idea of using drilled ruby or sapphire stones as bearings in English watches. At the time, natural gemstones were scarce and expensive, making jeweled watches a symbol of high craftsmanship and exclusivity.

It wasn’t until the early 20th century, with the development of synthetic ruby production via the Verneuil process, that jewels became affordable and widely adopted. By the 1930s, even mass-produced wristwatches from brands like Hamilton and Elgin included 7 to 15 jewels. Today, synthetic jewels are standard in virtually all mechanical movements, from budget Seiko models to high-end Patek Philippe calibers.

How Many Jewels Are Enough?

Modern mechanical watches typically contain between 17 and 25 jewels. A basic hand-wound movement with central seconds usually has 17 jewels—covering the mainspring barrel, gear train, escapement, and balance wheel. Additional jewels may be added for features like automatic winding systems or hacking mechanisms.

Some premium watches boast 30+ jewels, but beyond a certain point, extra jewels offer diminishing returns. For example, shock protection systems like Incabloc or Kif may add several jewels not for performance enhancement but to support spring-mounted balance staffs. While technically beneficial, these don’t contribute as directly to timekeeping accuracy as core bearing jewels do.

Be cautious of marketing claims suggesting that more jewels equal superior quality. A chronograph movement might have 36 jewels due to added levers and couplings, while a simple three-hand model with 21 jewels could be more refined in execution.

Tip: Focus on movement finishing, regulation, and brand reputation—not just jewel count—when evaluating a watch’s value.

Mini Case Study: Comparing Two Movements

Consider two popular automatic movements: the ETA 2824-2 and the Seiko NH35. Both are reliable workhorses used by numerous watch brands.

The ETA 2824-2 contains 25 jewels and is known for its robust construction, COSC certification options, and smooth operation. It uses cap jewels on the balance wheel and includes jewels for the automatic winding reverser mechanism.

The Seiko NH35, found in many affordable divers and field watches, has 24 jewels. Despite one fewer jewel, it performs comparably in real-world conditions, thanks to efficient design and durable materials. The slight difference reflects minor variations in gear train layout and rotor mechanism, not a gap in quality.

This comparison shows that jewel count alone cannot determine performance. Engineering, tolerances, lubrication, and adjustment matter just as much—if not more.

Step-by-Step: How Jewels Are Installed in a Movement

1. Design phase: Engineers identify high-friction pivot points requiring jewel bearings.
2. Jewel fabrication: Synthetic ruby rods are cut into small blanks and drilled with ultra-fine holes using diamond-tipped tools.
3. Polishing: Each hole and surface is meticulously polished to achieve mirror-like smoothness.
4. Press-fitting: Jewels are pressed into recesses (chatons) in the movement plate or bridge.
5. Securing: Some are held with screws; others are friction-fit and glued for permanence.
6. Final inspection: Technicians verify alignment and rotation under magnification before assembly proceeds.

Frequently Asked Questions

Do quartz watches have jewels?

Yes, many quartz watches with analog displays (moving hands) include a few jewels—typically 1 to 5—in the gear train. Since the motor drives the hands through mechanical gears, reducing friction remains important, though less critical than in fully mechanical movements.

Are watch jewels real gemstones?

No, modern watch jewels are almost always synthetic—lab-created corundum (ruby or sapphire). They offer identical physical properties to natural gems but are more consistent, affordable, and ethically sourced.

Can a watch have too many jewels?

Yes. Excessive jewel counts (e.g., 50+ in inexpensive watches) are often marketing gimmicks. Extra jewels in non-critical locations provide negligible benefit and may indicate poor design prioritization. Authentic high-complication pieces justify high jewel counts through complexity, not exaggeration.

Conclusion: Appreciating the Engineering Behind the Sparkle

The presence of jewels in watches is a triumph of micro-engineering, not opulence. These tiny components silently ensure that your timepiece runs reliably, accurately, and smoothly for years. Whether you own a vintage hand-wound watch or a modern automatic diver, understanding the role of jewels deepens appreciation for the craftsmanship involved.

Next time you peer through a display case back, don’t just admire the moving gears—look for the subtle red or clear dots nestled among them. Each one represents a solution to a persistent challenge: how to make something so small, so precise, endure the relentless passage of time.

💬 What surprised you most about watch jewels? Share your thoughts or ask a question—let’s keep the conversation ticking!