When you hear the term “jewels” in relation to a watch, your mind might immediately picture glittering diamonds or rubies adorning the bezel. But in the world of horology, the most important jewels are hidden deep inside the watch’s movement, working tirelessly out of sight. These tiny, functional gems are the unsung heroes of mechanical timekeeping, playing a critical role in the accuracy and longevity of your watch. So, what are jewels used for in a watch? This complete practical guide will demystify their purpose and show you why they are so vital.
Far from being mere decorative elements, watch jewels are precision components that serve a fundamental engineering purpose. They are synthetic sapphires or rubies, prized for their incredible hardness and smoothness, and they act as near-frictionless bearings for the moving metal parts inside the watch’s mechanism. Without them, the delicate dance of gears and levers would quickly grind to a halt due to wear and tear. This guide will walk you through everything you need to know about these tiny marvels.
What Are Jewels Used for in a Watch? – A Complete Practical Guide
At its core, the answer is beautifully simple: jewels are used to reduce friction and minimize wear. A mechanical watch movement is a complex assembly of tiny, rapidly spinning axles and levers. When metal rubs against metal at high speeds for years on end, it creates friction. This friction has two damaging effects: it wastes the energy from the mainspring, causing the watch to lose time or stop, and it grinds away at the metal components, generating debris that can clog the movement and lead to premature failure.
By placing incredibly hard, perfectly polished synthetic jewels at the pivot points of these axles and the contact points of levers, watchmakers create bearings that are vastly more durable and smooth than metal alone. Think of it like upgrading from a rough, dirt path to a perfectly smooth, glass highway for the watch’s energy to travel along. This allows the movement to run more efficiently, maintain accuracy for longer, and significantly extend its operational life.
The Different Types of Watch Jewels and Their Jobs
Not all jewels in a watch are created equal. They come in different shapes and are placed in specific locations to perform specialized tasks. The most common type is the hole jewel. These are donut-shaped jewels with a perfectly round hole in the center, and they act as bearings for the rotating gear axles (called pivots). Then there are cap jewels (or endstones), which are flat discs placed on top of hole jewels, creating an oil reservoir and further stabilizing the pivot.
For the parts that don’t just spin but also snap back and forth, like the pallet fork in the escapement, watchmakers use pallet jewels. These are rectangular jewels that capture and release the escape wheel teeth, a process that creates the familiar ticking sound. Another critical set is the roller jewel, which is mounted on the balance wheel and interacts with the pallet fork to keep the oscillator swinging. Each jewel has a precise role in the symphony of timekeeping.
More Jewels Means a Better Watch, Right?
This is a common belief, but it’s not always true. There is a functional limit to the number of jewels a mechanical watch movement actually needs. A standard time-only watch (hours, minutes, seconds) typically requires between 17 and 21 jewels to lubricate all its essential pivot points and lever surfaces effectively. Movements with additional complications, like a chronograph (stopwatch) or a calendar, will naturally require more jewels to protect their extra mechanisms.
Historically, there was a period known as the “jewel wars” where some manufacturers added non-functional jewels in places like the automatic winding mechanism just to inflate the jewel count on the dial. A watch with 90 jewels isn’t necessarily 90 times better than one with 20. The quality of the movement’s design, finishing, and adjustment is far more important than a high jewel count alone. Once you get past the functional number, more jewels don’t improve performance.
Why Synthetic Sapphires and Rubies?
You might be wondering why these specific materials are used. The answer lies in their physical properties. Synthetic sapphires and rubies are both forms of corundum, which is the second hardest natural substance on earth after diamond. This extreme hardness makes them incredibly resistant to scratching and abrasion. Furthermore, their crystalline structure allows them to be polished to an exceptionally smooth, mirror-like finish, which is essential for minimizing friction.
They are also oleophilic, meaning they have a strong affinity for oil. This property is crucial because the tiny amounts of special lubricating oil used in a watch movement cling to the surface of the jewels, creating a long-lasting film that further reduces friction. While they are called “jewels,” they are manufactured in laboratories, making them perfectly uniform, affordable, and ethically sourced, unlike their natural counterparts.
Caring for Your Watch’s Jeweled Heart
While the jewels themselves are virtually indestructible in normal use, the movement around them is not. The best thing you can do for your watch’s jeweled bearings is to ensure it is serviced regularly by a qualified watchmaker. Over time, the lubricating oils can dry out or gum up, defeating the purpose of the low-friction jewels. A professional service involves completely disassembling the movement, cleaning each part (including the jewels), re-lubricating them with the correct oils, and reassembling everything.
It’s also wise to avoid exposing your mechanical watch to strong shocks. A sharp impact can cause a pivot to snap, even if it’s riding in a jewel bearing. Treating your timepiece with care ensures that its intricate, jewel-protected mechanism will continue to tick accurately for generations.
In the end, watch jewels are a brilliant fusion of science and craftsmanship. They are not there to sparkle, but to serve. These tiny synthetic stones are fundamental to the reliability and precision we expect from a fine mechanical watch. By reducing friction and wear, they transform a collection of metal parts into a durable and accurate timekeeping instrument. The next time you glance at your watch, remember the hidden, jeweled heart that makes it all possible.