Jewels in watchmaking refer to small, synthetic ruby or sapphire bearings used to reduce friction and wear in the movement of a watch.
Jewels in watches are synthetic rubies or sapphires used as bearings at friction points within the movement — pivot holes, pallet stones, and impulse jewels. Their extreme hardness and smooth surface minimize friction and wear, extending movement longevity. Modern jewels are all synthetic (lab-grown), providing consistent quality without the brittleness of natural stones.
A standard mechanical movement needs 17 jewels to cover all critical pivot points. More complex movements (with date, chronograph, etc.) need more — 25-30 is common. Beyond functional jewels, some manufacturers add non-functional 'decorative' jewels to inflate counts. 17 functional jewels is the benchmark for a properly jeweled movement.
Not beyond the functional minimum. 17 jewels covers all necessary bearing points; additional jewels beyond that number are often decorative or used in complications. In the mid-20th century, some manufacturers used excessive jewel counts as marketing. Quality depends on movement design, materials, and finishing — not jewel count alone.