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Black and gold using gosiba acid

Hi I am planning on designing a piece of jewellery that would mainly be black (sterling silver) but would have some 18ct gold elements…I have been advised to use gosibaacid to blacke the silver…will this also oxidise the gold…I would of thought not…but want to check before I potentially ruin some gold. Also any suggestion of best way to create the dark black colour I’m going for would be appreciated

Tumbling with steel shot
Making sure metal is clean and dry
Coatingwith renaissance wax


I usually tumble a LOS oxidized piece of sterling silver as it gives it a nice polished finish. The piece should be polished first before you oxidize as the shot is finishing the oxidized surface, not the silver. Yes to clean and dry as you want all the dirt off or it will mask the oxidation. Yes to wax. I am not sure about the gold. I am also not sure about gosiba as I have never used it. Regardless of how the finish is achieved, it will likely lighten or even disappear in the high wear areas. Good luck…Rob

I never used gosiba acid but know of others that it don’t color gold, only silver brass and copper.
I found this link for you. Check it out.

Thank you

One of the benefits of Gosiba is that is is reusable. Keep it in a dark container in a dark cupboard, it is light sensitive and will loss straight if it is exposed to light.I dilute it Gosiba with a 2-3 parts water to 1 part Gosiba.
It leaves a nice dark black,you may need 2 applications to get it an even finish.Good luck,Eileen

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Normal LOS (potassium sulfide) will turn the silver black and not touch the 18k much.

In my experience, oxidizers turn the gold a kind of brown, potentially quite attractive. I haven’t used gosiba. But with black max and the like it is super easy to clean the color off the gold. I like to do that with the corner of a Pro Polish Pad for control.

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