Component record · Plates & finishing

Jewels

Verified

Small bearings or functional stones, historically natural ruby and now synthetic sapphire or ruby, used at points of high friction and wear in a movement.

What it does

Reduce friction and wear at pivots, pallet faces and the impulse pin, extending accuracy and service intervals compared with plain metal bearings.

How it works

A jewel bearing is a hard, highly polished hole (or pallet/impulse-pin surface) that presents far less friction and far greater wear resistance than a plain brass or steel bearing, particularly important at the fast-moving, lightly loaded balance-staff pivots.

Jewel counts became a widely advertised (and sometimes misleadingly inflated) marketing figure in the 19th and 20th centuries; a genuinely useful jewel count depends on placement (at points of real friction) rather than sheer number, and unnecessary or purely decorative jewels ('non-functional jewelling') were sometimes added to boost advertised counts.

Modern synthetic sapphire jewels are manufactured to extremely precise tolerances and are effectively interchangeable in quality with natural stones once used, since the crystal structure and hardness are essentially the same corundum material.

Evolution

From scarce, hand-shaped natural rubies affordable only in premium work, to cheap, precisely manufactured synthetic jewels that made high jewel counts affordable across nearly all grades of mechanical watch by the mid-20th century.

Known variations

Cap and hole jewels at balance pivots
Pallet stones
Roller/impulse jewels
Non-functional or decorative jewels used to inflate advertised counts

Identification for collectors

Visible as small red or clear circular inserts in plates and bridges around the balance and pallet area; jewel count is usually engraved on the movement