The term “jewel” refers to a type of bearing in a watch mechanism. Modern jewels are typically made of synthetic sapphire or ruby. Jewel bearings reduce friction, therefore they offer a high degree of accuracy in timekeeping. The number of “jewels” is often used to characterize the quality of a watch. A watch with 17 jewels or more would indicate a high quality, precision watch. Jewels in watches have little monetary value.