What Are Jewels in Watches?

A jewel in a watches refers to a small gemstone used as a bearing within the watch mechanism. Its primary function is to reduce friction between moving metal components, particularly in the gears and rotating parts. The term jewel comes from the historical use of natural gemstones like rubies and sapphires in watchmaking. Today, most watch jewels are made from synthetic materials with exceptional hardness and resistance to wear.

In general, jewels are essential in mechanical watches, whether manual or automatic. They are placed at critical points experiencing high friction to extend the lifespan of components and maintain time accuracy. Without jewels, metal-on-metal friction would lead to rapid wear, decreasing efficiency and shortening the watch’s lifespan.

The History of Jewels in Watches and Their Inventor

The use of jewels in watch mechanisms was first used around the 17th century. Initially, watches and clocks relied entirely on metal components, including the bearings for the pivots. Excessive friction caused rapid wear on gears and pivots, prompting watchmakers to seek solutions for improving durability and accuracy.

In 1704, Nicolas Fatio de Duillier, Pierre de Fazio, and Jacob Debaufre patented the use of rubies as bearings in watches. This innovation was first applied to pocket watches and quickly gained widespread recognition for its significant friction reduction. Ruby is chosen for its superior hardness and wear resistance compared to ordinary metals.

Over time, the use of gemstones became a standard in horology. By the early 20th century, companies such as Patek Philippe, Breguet, and Rolex played pivotal roles in refining jewel systems, making them essential components in high-quality watch production.

Functions of Jewels in a Watches

The primary function of jewels is to act as bearings that reduce friction between moving mechanical components. Below are specific roles of jewels in watches:

• Reducing Friction: Metal-on-metal contact produces friction, leading to rapid wear. Jewels significantly lower this friction.
• Improving Accuracy: By reducing friction, watches maintain better time accuracy since the components move more smoothly and freely.
• Extending Component Lifespan: Lower friction minimizes wear on gears and pivots, extending the watch’s longevity.
• Stabilizing Movement: Jewels help balance critical components like the escapement and balance wheel, ensuring stable mechanical movement.

What Is the Minimum Number of Jewels in Watches?

The minimum number of jewels needed in a simple mechanical watch is seven, which is sufficient to support core components like the escapement, balance wheel, and center wheel. Here’s an overview of jewel counts in various types of watches:

• 7 Jewels: Typically found in basic mechanical watches without complications.
• 17 Jewels: The standard for automatic watches with basic mechanisms.
• 21–27 Jewels: Found in automatic watches with multiple complications, such as date and day indicators.
• 30+ Jewels: Common in watches with complex features like chronographs or perpetual calendars.

While a higher number of jewels often correlates with more complex mechanisms, it doesn’t necessarily guarantee better quality.

What Happens If a Watch Has No Jewels?

A watch without jewels would face several significant issues. Here’s what happens when jewels are absent:

• Excessive Friction: Without jewels, metal components in contact generate high friction, leading to quick wear.
• Reduced Accuracy: High friction affects the speed and precision of moving parts, reducing the watch’s timekeeping accuracy.
• Shortened Lifespan: Without jewel protection, components like gears and pivots wear out rapidly, requiring frequent maintenance or replacement.

Historically, some cheap watches were produced without jewels, but were notorious for their unreliability and short lifespan. As a result, the use of gems has become a standard of quality in a watch.

Where Are Jewels Located in a Watch?

Jewels are strategically placed at high-friction points within the watch movement. Key locations include:

• Balance Wheel: Jewels support the balance wheel pivot to keep it stable.
• Escapement: Jewels reduce friction where the pallet interacts with the escape wheel.
• Gear Train: Each gear pivot is equipped with jewels to ensure smooth rotation.
• Rotor (in Automatic Watches): Jewels support the rotor’s movement as it winds the mainspring.

What Are Watch Jewels Made Of?

Initially, jewels were made from natural gemstones like rubies and sapphires. However, synthetic jewels have been mass-produced since the 20th century using chemical processes. Synthetic rubies are the most common due to their high hardness (Mohs scale 9) and resistance to heat and friction.

The production process involves heating aluminum oxide at high temperatures until it forms crystals. These crystals are then cut and polished into tiny sizes suitable for watch mechanisms.

Jewels are crucial components in mechanical watches, serving to reduce friction, improve accuracy, and extend the mechanism’s lifespan. Despite their small size, jewels play a vital role in ensuring a watch’s reliability and elegance. With technological advancements, the use of synthetic jewels will continue to rise, guaranteeing that watches remain precise and durable for years to come.