[Kristof]

I own a vintage Herodia handwound watch with a rosegold(plated?) case. There are no hallmarks visible on the case, the caseback or the inside of the caseback where you can usually find details on the quality/type of gold used. There is however a 90 in a square stamped on the caseback (90, not 9C). I've seen this on other gold Herodia watch casebacks on the internet but I can't find out what that 90 means. Can somebody enlighten me? Thanks in advance.

 

[Reflex]

To the best of my knowledge, that 90 indicates silver plate and that 90 grams of silver was used in the plating mixture. It's a way of documenting this.

 

[Kristof]

Aha. So the watch is actually silverplated. Do they also use gold for the rose gold colour or is this done using other elements or chemicals? Thanks for your input.

 

[Reflex]

It's the caseback that has the silver plating on this watch.

If there is some gold in the case of the watch, this should be indicated somewhere on the watch, normally under a lug. If not then it's most likely gold plating

 

[Kristof]

How fancy to have silver in the caseback. I thought it was just stainless steel. I'll break out the magnifying lens to check the watch case & the lugs. Can't see anything but my eyes aren't what they used to be. Thanks!

 

[AtomicTom]

Ooh cool, very cool Steve !!! 🥇🏆

Looks like Reflex has you covered Kristof, and given you some
really great insight. Man oh man, we are always learning
right? It's amazing actually.

Am so happy someone could help you out, and am happy you
are here too. 🙂..Welcome aboard !

 

[morningtundra]

I could be wrong (and often am) but I believe the case is plated. That discoloring is “brassing” where the plate coat is wearing thin and the base metal showing through. A solid gold case would have hallmarks indicating at a minimum, the gold quality. You’d also expect an Assay mark from country of origin and depending on the country an import stamp.