You often hear people say that the more jewels in a mechanical watch movement, the better. A standard mechanical watch movement requires 17 or 18 jewels but more than that doesn't mean it's better. Two watches with identical performance may contain a different number of jewels.
The jewels themselves are usually synthetic sapphire and are not valuable in anyway except to aid a timepiece's movement. Their low and predictable friction improves watch accuracy and bearing life.
In the 1960s, an "arms race" of sorts broke out as competing watch manufacturers made watches with as many as 100 jewels and marketed this as a benefit. In reality, these "improved" watch movements often featured 17-jewel movements with 83 non-functional jewels mounted in a nice design near the winding rotor.
In 1974, industry watchdog groups banded together and prohibited manufacturers from including nonfunctional jewels in the jewel counts found in advertising and sales literature.