# Mystery Metal



## sauvesean (Aug 16, 2012)

Full disclosure: I work for The Salvation Army, selling donated precious metals. I am not sure if I even have the right forum, but decided to try this. I sift through a lot of silverware, sterling silver jewelry, and scrap gold jewelry. My testing kit has nitric acid, and a Mizar M24 gold tester.

Recently, I acquired a dish that has a silvery look to it, and has some small pitting that made me believe it may be silver. It looks forged. There are no hallmarks. It has a slight oxidize surface. It is not magnetic. After taking off the outer surface with a dremel, I dropped some silver testing acid on it. There was absolutely no reaction, not even a blood red color. All the way up to a platinum concentration of nitric acid will not touch it; I may as well have dropped water on it. The Mizar M24 detects it as not gold. It scratches on a testing stone at around the same hardness as silver, and acid does not dissolve the scratch.

I have no idea what this metal is. Although I am convinced that it is not a precious metal, I still need to know what it could be in order to be sure that I am not encountering it in other places.

What is it? Please help.


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## its-all-a-lie (Aug 16, 2012)

Stainless?


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## jimdoc (Aug 16, 2012)

sauvesean said:


> Full disclosure: I work for The Salvation Army, selling donated precious metals. I am not sure if I even have the right forum, but decided to try this. I sift through a lot of silverware, sterling silver jewelry, and scrap gold jewelry. My testing kit has nitric acid, and a Mizar M24 gold tester.
> 
> Recently, I acquired a dish that has a silvery look to it, and has some small pitting that made me believe it may be silver. It looks forged. There are no hallmarks. It has a slight oxidize surface. It is not magnetic. After taking off the outer surface with a dremel, I dropped some silver testing acid on it. There was absolutely no reaction, not even a blood red color. All the way up to a platinum concentration of nitric acid will not touch it; I may as well have dropped water on it. The Mizar M24 detects it as not gold. It scratches on a testing stone at around the same hardness as silver, and acid does not dissolve the scratch.
> 
> ...



Can you post a picture?

Jim


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## sauvesean (Aug 16, 2012)

Thanks,

Here it is


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## sauvesean (Aug 16, 2012)

Yeah, I thought it might be stainless or something, but was confused by the slightly darker surface which I believed to be oxidation.

Thanks either way.


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## jimdoc (Aug 16, 2012)

I would guess stainless also. You should be able to tell by the weight if it was aluminum.
I think pure platinum would be fairly easy to bend, if that is what you were thinking it may be.

Jim


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## sauvesean (Aug 16, 2012)

Thank you both for your help


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## patnor1011 (Aug 16, 2012)

Stannous is your friend. Scratch few slivers in small test tube. Introduce AR then heat few minutes - then test. If you will see orange you will see money.


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## ctgresale (Aug 17, 2012)

Look to me like Aluminium that has been run through a high temp dish washer. I've got a few pieces that look just like that now, pieces that we bought new. That was what caused there discoloring.


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## RESET (Aug 17, 2012)

Looks like it could be cast aluminum. I have some cleaner here at work that will turn aluminum black like that. Maybe test the scratch with Vinegar. If aluminum it will have a slight reaction. Stainless won't react at all.


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## NobleMetalWorks (Aug 17, 2012)

if it's Al, you can make up a weak solution of Lye to clean it right up.

It looks thick like Al would be, if caste.

It might have been an ashtray of some type, because it looks like the middle was subjected to more heat than the outsides, and that would be right about the same length as a cigarette. 

There are a lot of things that come out of India that are hand caste from whatever metals are around. There is a huge dump site in the middle of Mumbai (Bombay) where about a million, literally, people live. They recycle the items that are dumped, then these hand collected and recycled goods are sold to people who make them into everything from clothes, to bags, to metal items, etc. This is all done by hand, in tiny workshops that surround the dumps. When they have metals that believe are similar, they are melted down and hand caste into items they can then sell. Literally, if this was an ashtray made in a place like that, there is no telling what metals might be in it. And there are a ton of consumer goods sold in the US, that comes from places like I am describing. It's possible this is what you are looking at. It doesn't look to be the quality of something that was machined stamped, machine polished, and machine marked for retail sale.

It's too bad Good Will doesn't buy an XRF analyzer, it would make your job of sorting tons easier.

Oh a different note, where does Good Will sell their precious metals?

Scott


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## kurt (Aug 25, 2012)

I see this is an older thread but thought I would post how to test for aluminum &/or zinc 

Aluminum - will not react with nitric (at all) but does react with HCL

Zinc - reacts with both nitric & HCL

so no reaction with nitric but reaction with HCL = Aluminum

reaction with both nitric &/or HCL = zinc

if its a high aluminum low zinc alloy nitric will produce a dack spot - or you could get pitting if the zinc is higher

Kurt


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## Evan2468WDWA (May 30, 2014)

I know this is unlikely, but maybe it's Rhodium plated sliver. Rhodium doesn't respond to acids. Here check out these links.
https://www.youtube.com/watch?v=H7Ng4sOVkns
http://www.everything-wedding-rings.com/rhodium-plating.html


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## necromancer (May 30, 2014)

you can always try the taste test, 
that looks cheap pressed aluminium. ""look how the edges are rolled""

corroded or warn aluminium has a bit of a acidic/metallic taste
plated silver if corroded has a dirty or musty/metallic taste

just wipe it off before you touch the end of your tounge on it :mrgreen:


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