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The Encyclopedia of Horology

Glossary · Mechanism

Jewels

Hard synthetic or natural stone bearings reducing pivot friction and wear.

Explanation

Jewels are working bearings and escapement stones. A hole jewel supports a pivot radially; an endstone controls endshake at the pivot end; pallet and impulse jewels act in the escapement. The advertised total can combine all of these, so the number alone does not reveal layout, condition or quality.

Setting style is also evidence. Screwed chatons, rubbed-in jewels and friction-fitted jewels belong to different manufacturing and repair practices, but they overlap historically. A gold chaton can indicate high-grade finish in one context and replacement or decoration in another. Identify the exact calibre before using jewel count or setting style as evidence.

Sources & references

  1. de Carle, D., Practical Watch Repairing — jewelling
  2. Daniels, G., Watchmaking — bearings and escapement stones

Where sources disagree, the disagreement is stated rather than resolved silently.

What to record

  • Separate stated count from professionally verified count.
  • Identify hole jewels, endstones and escapement jewels by function.
  • Compare setting style against a documented example of the same calibre.

Do not remove bridges to count hidden jewels unless the watch is being serviced by a specialist.