What are Watch Jewels? What does "21 Jewels" mean?

As I delved deeper into the watch world and hobby, it seemed like more questions kept coming up. Which is why I am determined to learn more and share my interpretation and answers to all theese questions with YOU. 

What are Watch Jewels?

I have never been a big user of jewelry (besides my watches of course...), which is why I became a little shocked, when I looked closer at my automatic pieces (now consisting of a Seiko Skx009 and Seiko Snk809). 

It says: "21 jewels" on both of them. So does that mean they contain jewels (diamonds, sapphire and rubies) and other precious stones?? 

Seiko Snk809

Model: Seiko 5 Snk809 


What does "21 jewels" mean?

 As all watches have many moving parts, jewels were inserted to lessen the wear and tear on the bearings and other pivot points.

Meaning all the rotating parts and other high frictional points in the watch; which before were metal againts metal parts, were exchanged with hard jewels. 

Back in the days it was natural jewels (diamonds, sapphire and rubies) which were grinded and put into the watches.

Now adays you can use various tecniques to produce synthetic jewels, which makes the movements cheaper. 


Seiko 5 Snk809 jewel 

See the pink jewel sitting in the rotating wheel?


The jewels basically make the watch movement last longer. As it reduces the metal to metal frictional tear, thus reducing service needs and keeps the inside mechanics better aligned, which increases the accuracy.  

 It is not a "BLING FACTOR", unless it is real diamonds inserted of course... 

Does More Jewels Equal Better watch? 

As for the referenced watch above (Seiko 5 Snk809), which has one of Seiko´s highly used and robust movements (the 7S26), there are 21 jewels inside. 

I assume Seiko use synthetical jewels and that they have made many attempts, in trying to create the best movement, with the most optimal amount of jewels inside. 

Because more jewels inside a watch, doesn´t neccessarily mean a better movement. Just because you CAN put a shiny little rock in every frictional or pivotal point, does not mean you SHOULD... 

 Seiko 5 Snk809 watch  


Jewels in Short: 

  • Synthetically made (typically) 
  • Mainly used in Mechanical watch movements (which has more moving parts) 
  • Reduces friction in bearings and pivotal points (meaning less frequent service) 
  • Keeps the mechanical parts better aligned, meaning better accuracy of the watch 


Hope you took some knowledge away from my post and feel free to comment below, if you have any further questions. :-) 



  • Well, the essence of using jewelry is to reduce friction hence promote accuracy and longevity in your priced watches. Jewel act as oil in the engine of a car.

  • Hi Adeel,

    If it says 21 jewels, then there are 21 jewels inside all the pivot/frictional points. Depending on the watch design, the amount of jewels can differ. So yes you could have a watch with 30 jewels, but it would then be more complicated than necessary.

    Alex (Strap Change admin)
  • I almost understand the meaning but I still wonder y they write 21 jewels I mean they can 30 jewels or any other numerics?

    Adeel Atta
  • Hi Adrian,

    Glad I could help with this blogpost. It all makes more sense, when you actually disassemble a mechanical watch and see the moving parts.. But a Seiko SNK809 with a displayback is also very educational.

    Alex (Strap Change admin)
  • Thank you! I’ve been wondering about the jewels used in automatic watches as well, it all makes more sense now :)


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