Contaminated gold

Hi everyone,

I have been melting down old pieces of jewelry and I think I have some kind of contamination happening.

When I melt the metal (usually 14 or 18k gold) I do test it prior to and after casting. The acid test says it is somewhere between 14-18k. BUT it looks suspiciously yellow to me, brassy.

Funny thing is, on the same tree I can have two pieces that come out looking different.

When I test after casting it comes out saying between 14-18k but the color is quite unsettling to me. Please note that I am enameling these.

Can anyone advise? Should I send the remainder out as scrap to Rio perhaps?

I’ve thought about this and I don’t have any good ideas. If it’s all testing as gold, then I think that it’s got to be gold.

It’s probably some kind of surface discoloration. Have you tried polishing or sanding?


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The thing is when melting down various pieces you don’t know what recipe is in the alloys. Your new alloy is going to have a mishmash of whatever is left with ratios all over the place. That will change the color for sure.

There could also be solder.

Zinc is going to burn off every time you melt, changing your end alloy after several iterations.

Another possibility is if there happened to be any gold-filled pieces by accident. That’s going to dope your alloy with extra copper.

Any used gold I buy goes to the refiner, and I use that money to buy new gold so I know exactly what is in the cast.


I had this problem with a collection of what were stamped 14K chains.The customer wanted me to melt them down into an ingot, draw them into wire and make a chain bracelet. I was able to do this, but the metal, while testing OK, just worked differently than new metal. While I don’t like to do this process, I have done it several times after making sure that the customer knew that the hole project could fail for several reasons…Rob

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I was thinking perhaps there was solder as well. Thanks for all the info!

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Yes I have sanded and polished- the color lightens up a bit but still seems suspect. Will be sending the leftover to a refiner. If I get any additional info I will update everyone here

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Thank you for responding, I think your disclaimer is smart and important!

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