How to test silver items

February 16, 2009 8:33 PM

I want to test the silver content of some items. What should I buy? I see people offering silver testing kits on Ebay. Are these a good choice, or would I better off buying the reagents themselves? If so, which ones?
posted by Joe in Australia to science & nature (5 comments total)

Do you want to determine if there's silver present, or are you trying to figure out the percentage?
posted by Chocolate Pickle at 8:36 PM on February 16

The percentage.
posted by Joe in Australia at 8:53 PM on February 16

I am no expert, but I just took a look at eBay for those kinds of kits, and I think those were all qualitative, not quantitative. They'll tell you if silver is present and give you a general idea of whether there's a lot or just a little, but I think that's all they'll tell you.

A reliable quantitative test would either require spectroscopy, or a very accurate scale. I don't see how it could be done just using a few dropper bottles of magic solution.

Also, determining the percentage without spectroscopy would require using acid to dissolve a significant amount of the suspect metal (e.g. a gram or so) which would do violence to the object you were testing.
posted by Chocolate Pickle at 10:51 PM on February 16

Agreed- the testing kit surely can only tell if there is silver present, not how much or whether it's silver plated or pure silver.

What kind of items are they?

I can tell you this from experience, don't know if it will be helpful. Silver coins make a different sound when they are dropped. There is a sustained ringing sound, and its a slightly different pitch. Where a silver plated coin or a non silver coin has a much "deader" sound.

To find the percentage, you'd probably have to know what the other metals are. But you could probably ball-park it by finding out the volume of the thing, weighing it, and then doing some math on the mass of silver versus the mass of other metals.
posted by gjc at 6:27 AM on February 17

I have a gold testing kit. Its made up of four stoppers of hydrochlouric acid (HCL). They are all different concentrations, and allow me to verify the Ct's in gold. ie. 9ct, 14ct, 18ct, 22ct etc. I would sugest messaging one of the sellers, and asking if it can verify silver content for you.

as gjc mentioned, silver coins will "ring" when you drop them on a hard surface, once you know what sound you are listening for, its quite distinguishable.
posted by dent8101 at 5:50 PM on February 17