Hello,
This is an Elgin pocket watch size 0.

Notice the setting is the same mottled finish on the lower setting as well, both cap and hole jewels.

Thanks,

Joel Trenalone
www.timepieceshoppe.com

lower jewel image:

Oh, one other thing, it looked the same after a trip through the cleaning machine

Hi Joel,

is the balance oscillating regularly?

rgds

Enzo

Enzo,
Yes, the watch runs great, good amplitude, and timing good. The jewels themselves are in good shape. The settings just look strange. I am willing to leave well enough alone, but was curious,
Joel

I think Lin is on the right track, the greenish coating that forms on corroded copper, brass or bronze is called verdigris. In a watch the corrosion could be caused by contact with perspiration or contaminated cleaning solutions.

Quoting from Wikipedia:

Verdigris is the common name for the green coating or patina formed when copper, brass or bronze is weathered and exposed to air or seawater over a period of time. It is usually a basic copper carbonate, but near the sea will be a basic copper chloride . . . Its name comes from the Middle English vertegrez, from the Old French verte grez, an alteration of vert-de-Grice ("green of Greece"). The modern French spelling of this word is vert-de-gris.

Lindell, Ed,
Thanks for the info. I have seen brass coating/corrosion before, but this mix of white and green seem unusual to me. But perhaps it is due to the fact that the part is so small. I think it is simply corrosion on the brass. It also struck me odd that it was equally on all four settings.

Well, anyway I think this is solved. I might just leave it alone.
Thanks for the input, as I had not heard the Verdigris term. I am concentrating my study of late on metallurgy, so this info is helpfull.
Thanks,
Joel

I have seen many colors and crusty build ups on these jewels in the past, often formed from old oils, and various concoctions that have been put on to get the watch working
It should scrape off easily, worst case pop them into the lathe and lightly skim back with the back of a graver or remove with very find paper.

I've also seen balance hole jewels that were corroded like this. Care must be taken when scraping the crud off of these so that the lip that holds the jewel into the setting isn't removed.The first time I did this everything stayed into place until I ran the watch on the rate recorder. It sure made a lot of errant noise's on the recording. I didn't find the problem until I looked at the assembly though my microscope while it was running. Then I could see that the hole jewel was wobbling around in the setting.