Discover the hidden jewels that reduce friction and extend a watch’s life

Why Do Watches Need Jewels at All?

These jewels are not decorative but deeply functional, industrial-grade instruments which reduce friction, maintain positional stability, hold lubricants in micro-cups designed to retain oil, and ultimately safeguard the long-term accuracy of the watch. Without them, the delicate choreography of gears, levers, and wheels inside a movement simply wouldn’t endure the test of time.

To understand their role, imagine the inside of a mechanical watch: a dense architecture of gears, axles, wheels, and levers, all in constant motion. Whether powered manually or automatically by wrist movement, these parts must move with extreme precision. Some components rotate at incredible speeds — the escape wheel, for instance, can spin over 100 times per minute. Metal parts rubbing against metal under such force would wear down quickly, much like a bracelet clasp getting scratched with daily use. And when components wear down?

The watch begins losing accuracy: a disaster for any collector who values precision. This is where jewels come in.

The Function of Jewels

Reducing Friction: Watch jewels act as bearings, each with a precisely drilled hole through which the pivot of a wheel runs. Made from ultra-hard, ultra-smooth synthetic rubies or sapphires, they dramatically reduce friction inside the movement. The result is smoother operation, less wear, improved accuracy, and a longer lifespan for the watch.

Holding and Retaining Lubrication: Jewels are designed with tiny oil-retaining pockets. Inside a movement, lubrication is everything — without it, gears grind, pivots score, and metal dust builds up, slowly choking the mechanism. A jewel’s cup-like shape holds microscopic droplets of oil exactly where they’re needed, ensuring the watch runs seamlessly.

Enabling Complex Complications: The more functions a watch has — date windows, day indicators, moonphases, chronographs, perpetual calendars, the more moving parts it must coordinate. More moving parts mean more bearings, hence more jewels. This is why a simple three-hand dress watch may have 17 jewels, while a chronograph or perpetual calendar may boast 25, 31, or more.

Tracing The Evolution Of Jewels

Early watches used metal-on-metal contact for pivots and gear trains. As these components spun thousands of times a day, they wore down quickly, causing loss of accuracy and frequent repairs. To overcome this friction, Swiss mathematician Nicolas Fatio de Duillier pioneered the use of hard gemstones as bearing surfaces, an innovation that transformed the stability of early movements. Back then, watchmakers relied on natural gemstones like diamond, sapphire, ruby, even garnet to create these tiny bearings. Especially rubies because of its exceptional hardness and smooth crystalline structure. But natural stones were inconsistent in purity, difficult to shape, and prone to microscopic imperfections that could cause cracking during manufacture.

But the craft shifted dramatically in 1902, when the process for producing synthetic sapphire and ruby (corundum) was invented. Suddenly, the precision of jewel bearings became far more accessible, no longer limited by the rarity or cost of natural stones. Today, nearly every jewelled bearing you see inside a mechanical watch is crafted from synthetic ruby or sapphire: materials engineered to be perfectly uniform, incredibly hard, and ideal for the relentless dance of gears that define modern horology.

This is why older watches proudly displayed the phrase “17 rubies” on the dial, whereas modern pieces say “17 jewels” — a nod to updated materials without losing historical language.

How Are They Made?

Modern synthetic jewels are produced through high-temperature crystal-growth processes and then laser-cut into exact geometries with tolerances measured in microns. Each jewel is shaped into a bearing with a precisely drilled hole at its center, forming the low-friction channel through which a wheel’s pivot rotates. The surfaces are polished to a mirror-smooth finish so that even components spinning over 100 times per minute experience minimal resistance. Their hardness, second only to diamond, ensures they do not deform under pressure, while their chemical stability prevents corrosion, oxidation, or oil absorption.

Jewel Counts: What Does the Number Actually Mean?

Flip a watch over, and you might see “17 jewels” or “25 jewels” engraved on the movement. This number simply indicates how many pivot points are being supported by jewels—not how “luxurious” the movement is. A higher jewel count doesn’t automatically mean a better watch; it reflects the complexity of the mechanism.

17 jewels → Standard hand-wound or automatic movement

21–25 jewels → Automatic with added functions

30+ jewels → Complications like chronographs and perpetual calendars

Watches With Diverse Jewel Counts