# Dirty, dirty, dirty



## Cozza (May 25, 2019)

Good evening all,
I did my first silver waste bucket clean out today. The result is some DIRTY silver. After melting, the shot was quite beautiful. Now I can see plenty of copper in it but can the copper give the silver that gold tint as well? If not what could it be? This is from my first kg processed from our Aussie pre decimal coins, munted up flatware and a couple of damaged pepper pots.
Any insight would be most appreciated.
I will likely throw this lot in with the next sterling batch I process.


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## renkenbw (Jun 8, 2019)

I had something very similar when I made a mistake trying to cement out silver. It’s a longer story that I have for here, but I’m sure that what I had was a mix of copper and silver. When I melted it and poured it into water, like you, I had copper, silver, and a mix of the two, which looked like gold. I re-digested this in nitric acid, and went through the proper procedures the next time, and got just the silver out.


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## kurtak (Jun 9, 2019)

Cozza said:


> I can see plenty of copper in it but can the copper give the silver that gold tint as well?



Yes - copper alloyed with silver will result in an alloy that is gold (yellow) in appearance - but its actually the silver causing the copper to take on the yellow/gold appearance - this is known as a "bleaching" effect

White metals like nickel, silver, the PGMs, zinc, etc. have this bleaching effect when alloyed with gold or copper & that's because it does not take a lot of the white metals to change (bleach) the color of gold or copper

You would think that the darker colors would dominate when alloyed with the white metals but its the other way around

That's why brass is yellow - "around" 30 % zinc 70% copper - take it up to 50% zinc & it becomes "white" brass

Nickle brass "around" 30 % nickel 70 % copper makes a "white" brass often referred to as nickel silver or German silver because it bleaches the copper to a "silver" white color - not because it has silver in it - there is no silver in it - the nickel gives it the appearance of silver

White gold - again "around" 30 % white metal (usually platinum, palladium &/or nickel) bleaches the gold to a "bright" silver white

Kurt


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## Cozza (Jun 10, 2019)

Kurtak,
You are a fountain of knowledge!
Fascinating info.


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