Rough and pitted jewel - What are the causes?

[ddrescueb2048]

I was inspecting the jewels in a Seiko 7019 and noticed a couple of them were very rough and pitted. Here is an example, the escape wheel main plate jewel. I was very thorough in cleaning it to the point where I removed it from the main plate to scrub it harder! :)

Does anyone know what causes something like this to happen?

 

[Michael1962]

As the bearing of the jewel to the pivot is the central hole and the immediate surface around it, the outer edge condition can possibly be like this?
Price vs quality?

I’m a newbie by the way, so take my comment as exactly that. Just a comment.  

Edited November 15, 2020 by Michael1962

[watchweasol]

Hi  If the finished portion (bearing surface ) is in good condition, no cracks/chips the outer surface is irrelevant, I may have been finished in that condition or it may be that some lubrication/ cleaning agent has reacted with it but as the brearing surface is ok I would suspect the former.

[ddrescueb2048]

Michael1962 and Watchweasol,

Thanks for your replies. The inner hole portion is in good condition as well as the back side where the cap jewel rests. Really, all surfaces are mirror smooth aside from the flat side. I first wondered about chemical damage but other jewels and the pivots look okay.

That was my guess as well; just what you get with a cheap movement. The pivot looks good after all these years so, I believe you're right, this is likely irrelevant.

Thanks again!