Why Watches Have Jewels

Seventeen jewels. Thirty-seven jewels. Set the numbers beside one another and a ranking almost writes itself. Surely the movement with more stones must be better?

Before accepting that conclusion, ask a quieter question: what is each stone doing?

NOMOS currently lists 17 jewels for its hand-wound DUW 4001 in the Tangente reference 139, and 37 for the automatic DUW 3001 in the Tangente neomatik reference 175. Those are two different constructions, not scores awarded to the same examination. The figures identify a feature of each movement. They cannot, by themselves, settle which is more accurate, more carefully finished, or more appropriate for its owner. Tangente 139 specifications, Tangente neomatik 175 specifications

The real story is more interesting than a contest. Watchmakers put jewels to work where surfaces meet, turn, and exchange forces. A familiar word from jewelry acquires a thoroughly practical meaning.

A bearing before a gemstone

Consider a wheel turning inside a movement. Its axle needs support, and the ends of that axle, called pivots, must turn in carefully located bearings. In a common watch bearing, the pivot passes through a precisely made hole in a small jewel.

The Fondation Haute Horlogerie describes modern watch rubies as synthetic stones, drilled and polished for use at pivots to reduce friction and wear. Ruby is a form of corundum, or aluminum oxide. The material’s usefulness here depends on its physical properties and the quality of the working surfaces. It does not depend on the romance of finding a gem in the ground. FHH on ruby

Imagine examining a movement photograph, then replacing the question “How many red dots can I see?” with “What turns at that point?” The color begins to describe an arrangement of working parts. You have moved from counting decoration to reading a machine.

The jewel does not create energy. It helps the mechanism use the available energy with less loss at a contact that still has to support and guide a moving part. That distinction explains why an apparently tiny component deserves care.

The hole is part of the engineering

A simple bearing jewel does more than offer a hard surface. Its hole must suit the pivot, and its position must suit the assembly. Horopedia describes a recess around the hole that holds lubricating oil. It also describes jewels fitted directly into a plate or bridge, and others held in a separate setting called a chaton. Simple bearing construction

These details make the word “jewel” less vague. There is a shaped component, a supporting structure, a moving partner, and a lubricant. Success depends on their relationship. A fine material does not rescue an incorrectly fitted part.

Nor must every possible bearing use the same material. Horopedia notes that some larger pivots carrying substantial torque can run in metal bearings. The sensible question is whether the chosen bearing suits its particular load and motion, rather than whether every visible location contains a ruby. Bearing materials and applications

A component’s absence from the jewel count is therefore not, on its own, evidence that a watchmaker forgot something.

Some stones have a different assignment

A pierced jewel guides a pivot, but another kind of jewel can support its end. This unpierced component is commonly called an endstone or cap jewel. In an endstone bearing, two stones perform related jobs: one guides the pivot through a hole; the other provides the end surface and helps control movement along the axle’s direction. Horopedia’s diagrams show why those roles require different shapes. Bearings with endstones

The distinction is small enough to disappear in an advertisement and large enough to matter in the workshop. Two jewels do not automatically mean two wheels. A single pivot may belong to a bearing arrangement that uses more than one stone.

Other jewels work in the escapement, the mechanism that controls the release of energy and helps maintain the balance’s oscillation. In a traditional Swiss lever escapement, two pallet stones meet the teeth of the escape wheel. Their surfaces participate in locking and impulse, rather than simply forming holes for rotating axles. Horopedia on the pallet lever, FHH on pallet stones

Already, the count covers several kinds of work. Treating all those stones as interchangeable units of excellence leaves the most useful information out.

Hard does not mean indestructible

Synthetic ruby offers a controlled material for precise components. Horopedia’s French-language materials entry describes crystal growth followed by cutting, shaping, drilling, and polishing. It also identifies brittleness as a limitation. Making the material consistently does not remove the need to handle and install it correctly. Horopedia’s ruby materials entry

At the balance, shock protection addresses another vulnerability: the small pivots supporting the oscillating assembly. A shock-protected bearing allows carefully controlled movement of its setting and endstone under impact, with a spring helping retain and return the assembly. The protection comes from the arrangement of parts, not from assuming that a jewel alone makes a watch shockproof. Shock-absorber construction

That is another reason a total cannot substitute for understanding. The same number tells us little about how stones are mounted or what protection surrounds them.

The oil still matters

A jeweled movement still depends on appropriate maintenance. A hard bearing surface does not make lubrication irrelevant.

Horopedia’s account of movement lubrication emphasizes the choice and quantity of lubricant at particular points. Too much, too little, or an unsuitable product can compromise operation. This is careful assembly and service work, rather than a matter of adding a generous drop wherever a stone is visible. Movement lubrication

For an owner, the useful response is to follow the maker’s care guidance and discuss the movement’s condition with a qualified watchmaker. The jewel count cannot diagnose dried lubricant, identify a damaged pivot, or establish the history of a watch offered for sale.

A high number engraved on an old movement is still a number. An assessment of its condition requires evidence about the object in front of you.

Read the number as an invitation

The comparison between the two NOMOS calibers is a useful place to return. Their totals tell us where a closer examination might begin. Understanding the difference fully would mean studying the respective constructions and identifying what the components do, not assigning each extra jewel a share of the watch’s price.

A jewel count describes a construction; it does not grade the whole watch.

That does not make the number meaningless. It makes it a starting point for a better question. Ask about the movement’s layout, the parts needing support, the bearing choices, and the quality of execution. Ask what servicing reveals that a specification cannot.

The stones inside a watch are worth appreciating because they make difficult work look uneventful. Something turns where it should. A contact surface does its job. Energy reaches the next part of the mechanism. The beauty lies in those quiet successes, whether the owner notices the jewels through a display back or never sees them at all.

Discussion: When you look at a movement, which would you most like a watchmaker to explain: a jewel bearing, the escapement’s pallet stones, or the balance’s shock protection?