You've probably seen phrases like 17 jewels or 23 jewels on movements. What should you understand by seeing this? Let's take a look...
Mechanical watches We know that many parts work together through their interrelationships. These parts need to interact properly. And there's a small detail that ensures this proper interaction: jewels. While the number and types of these jewels aren't critically important, it's still necessary to know about them.
Jewel is a synthetic gemstone used to reduce friction between moving parts within a movement, increase durability, and ensure precision. Movements contain many components, and they must be operated precisely and efficiently. As you know, metal parts wear out over time. One of the materials used to prevent this wear is the jewel we're talking about. The combination of all these elements results in less wear, less friction, and, consequently, improved precision.
Synthetic ruby, the primary material for jewelry, is used in recent watches. Ruby's high hardness naturally causes less friction. The reason for using synthetic ruby is likely due to its lower cost and mass production. Consequently, synthetic ruby is preferred over natural ruby.
The term "jewel" is used in many parts of the mechanism. You can see it in escapements, wheels, rotors, and spring mechanisms. When you see the term "jewel" in these places, you'll also see numbers like 17, 21, 25, etc. 17 is a number you'll see very often. 17 is generally considered the number that fully performs its function in a mechanism. In watches requiring higher precision...tourbillon You might also see the term 25 jewels (like this).
