Jewel bearings (watch movements)

Ruby jewel bearings are stone bearings in a watch movement, used to reduce friction where pivots move. The English word jewels may appear on movements and dials to indicate movement stones. These are functional components, not merely decoration.

Synthetic stones

Modern movement jewels are usually synthetic. Synthetic ruby is a real material with properties useful to watchmakers, not a claim of natural gemstone origin. A red stone visible in a movement should therefore not be presented as an expensive natural jewellery ruby without documentation.

What does the jewel count mean?

An inscription such as “17 jewels” indicates the number of movement stones. These can perform several roles, including bearings, endstones and pallet stones. The jewel count is therefore not necessarily a count of identical bearing holes. Nor is it, on its own, a measure of precision, condition or collectible value.

Practical checks

Compare the stated jewel count with documentation for the actual calibre, not another watch that merely looks similar. If a damaged bearing is suspected, have a watchmaker examine the movement. Do not dismantle it to count the jewels. Record calibre, running observations and service history separately, so that a high number does not replace an actual condition assessment.

Browse watches and pocket watches.

Sources

Fondation Haute Horlogerie: Jewels; Fondation Haute Horlogerie: Stone; Fondation Haute Horlogerie: Synthetic ruby.