# "Silver metal" stamp?



## cadfinger (Jun 15, 2017)

I was picking through some silver flatware and came across a spoon stamped "silver metal". looks like silver, tarnish looks like silver. Filed and tested with 70% nitric acid = green active reaction (not creamy white) with a bit of brown fume, calms to a very nice siver nitrate blue. I dabbed a bit onto filter paper and it looks like silver nitrate blue (not green). The file groove did not discolor like plate silver though. The spoon has no other markings. Any thoughts? Is it likely silver?


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## kernels (Jun 15, 2017)

Isn't Silver Nitrate colorless ? I dissolved some pure silver in Nitric acid while trying Hoke's experiments a few years ago, pretty sure the solution was clear.


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## FrugalRefiner (Jun 15, 2017)

You are correct kernels. Silver nitrate is nearly colorless. Copper nitrate can range from blue to green.

When dissolving sterling, you get a nice blue solution. The silver imparts no color, the bit of copper is a nice blue. But I could probably come up with other alloys that might create a blue solution with nitric.

"silver metal" doesn't mean anything to me other than a description of the color, like saying aluminum is a silver color.

For silver, Schwerter's solution gives a definitive test. I wish I had more to offer.

Dave


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## 4metals (Jun 15, 2017)

Just because silver is used in the name, doesn't necessarily mean there is silver in it. An example is "German Silver," it is copper, zinc, and nickel. But the color is like silver.


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## goldsilverpro (Jun 15, 2017)

"Silver metal" is not a legal mark and it could mean anything, Silver plate (probably), for example. I've always felt that, if someone makes a piece of sterling flatware, they will stamp Sterling on it Otherwise, they might have trouble selling it at a sterling price.

I once paid sterling price for a plated spoon or fork made by the Sterling Mfg. Co.


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## goldsilverpro (Jun 15, 2017)

cadfinger,

No duplicate posts allowed. I deleted your other one.


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## cadfinger (Jun 15, 2017)

Sorry for the double post. I'm new here but I'll get it figured out. Im new to refining and reading hoke in my spare time but I haven't gotten that far. The couple of times I have used nitric on small amounts of sterling I've ended up with a clear blueish solution after filtering. When I precipitated the silver with copper wire the solution seemed to be very greenish. I assumed that was because of the copper nitrate. Thus I assumed the silver nitrate contributed to the blue. Seems that I'm off as a little.


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## g_axelsson (Jun 16, 2017)

Silver nitrate reacts with chlorides ions (HCl, NaCl = table salt... for example) and gives a white precipitate.

Make some salt water and pour it in a silver nitrate solution. When no more silver chloride is precipitated then there is no more silver in solution. You can use this as a crude silver test or as a way of extracting silver from a solution, just filter it off. If you want to turn it back into silver, don't let it dry out. It's a lot easier to work with wet silver chloride than with dry.

Silver chloride left out in the sun turns purple over time.

The only other metal that forms insoluble chloride is mercury, but for a spoon I don't think the risk of running into mercury is something to worry about.

You could jump to the silver chapter in Hoke and do the silver acquaintance experiments she suggests.

Göran


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## FrugalRefiner (Jun 16, 2017)

Lead also forms a relatively insoluble chloride. It is more soluble in hot water, less so in cold water.

Dave


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## g_axelsson (Jun 16, 2017)

You are correct, lead would also precipitate if in high enough concentration. I've never seen lead nitrate mixed with a chloride so I can't say if it precipitates as needle like crystals. I think that the photosensitivity and turning purple if left in the sun is unique though.

If a white cloud forms then there might be silver but if no cloud forms then there is no silver in the nitrate solution.

Göran


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## flyfisherman (Jun 20, 2017)

For a fast silver test there is probably nothing better than silver testing solution that can be easily bought on Amazon. Tested metal should be scraped deep with the knife or other sharp tool and a drop of testing solution applied. After 7-8 seconds the tested site is wiped with paper towel. If color is red , it is real silver (80% silver, sterling, or higher purity). If color is blue, gree-blue, anything but red(or red-brown in case of lower purity silver)- it is not silver. Or one can use 18k testing acid . Tested metal (jewelry, spoon, candlestick, etc) is rubbed on the testing stone until there is nice thick line a 4-5 mm wide. A few drops of 18k acid applied next. If the metal is solid silver a bluish- white film of silver chloride will form. If metal is not silver the testing line will dissolve and dissappear. If metal in question is heavily silver-plated when the beginning of the testing line change to silver chloride, but the end will dissolve.


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## cadfinger (Jun 21, 2017)

Thanks for all the great info. I think a little silver testing solution and a file should tell me all I need to know. I'm curious about the stamp I haven't seen so I'll post a follow up when I get it figured out. It appears to be solid not plated (probably an alloy of some type).


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## Topher_osAUrus (Jun 21, 2017)

A good triangle file is what i prefer to use.
But, sometimes the plating can smear and skew the test result considerably. Usually that only happens if its pretty thick plating.

So, if that be the case -when testing unmarked stuff- i like to put a drop of strong nitric on the file mark and watch the color. It can get a little bit blueish from the 7.5% copper in the alloy. After letting it work a minute, I wipe it off, then put another in the same spot. I do this 4 or 5 times before im satisfied. If it gets a deep blue or green colour, I know its bunk.

I have almost been duped by a silverplate article that was silver plated onto lead or some other pot metal junk. The spot where the nitric was, ended up blackened instead of a creamy white spot. 

There isnt anything wrong with using Shwerters solution instead of nitric, I sometimes just prefer to see the untainted (no dichromate) reaction of it. Its good to have, and be familiar, with both.


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## cadfinger (Jun 28, 2017)

I have come to a conclusion. Thanks for all the input. The "Silver metal" stamp is definitely not silver. Both nitric and silver testing solution with a deep file groove confirm that this is a solid alloy, not precious metal (probably nickle/copper).


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