Watch jewelsJewels Watch jewels are small, synthetic sapphire or ruby bearings that are used in mechanical watches to reduce friction and wear on moving parts. They are typically made from corundum. They are used as bearings for a.o. the pivots to reduce friction. [Learn More] are small, synthetic sapphire or ruby bearings that are used in mechanical watches to reduce friction and wear on moving parts. They are typically made from corundum. They are used as bearings for a.o. the pivots to reduce friction.