How to Identify Pure Silver
The best way to prove pure silver is to make silver sulfide in one of two easy ways.
Anyone who collects silver tableware, cutlery or jewelry should know how to identify pure silver when they come across the shiny metal at yard sales or in junk shops. In many cases terrific bargains can be had at an uninformed merchant’s expense!
There are two easy ways to determine if a shiny metal is in fact silver. Both methods require a chemical reaction to occur on the surface of the substance and then a visual inspection for the presence of silver sulfide (a black stain on the metal).
FRENCH’S BRAND YELLOW MUSTARD TEST
This first method requires that the tester apply a very small amount of French’s brand yellow mustard to the surface of the shiny metal. Ideally, the mustard drop should then be heated, either in the sun or with a cigarette lighter. Let me explain; this brand of mustard contains a very high amount of sulfur and when heated the volatile sulfur molecule will ALWAYS combine with pure silver to make the dark black stain known as silver sulfide (which is easily cleaned away with vinegar by the way).
THE SULFUR MATCH TEST
This second method is anything but discrete–it may attract more attention than desired, especially when attempted inside. Yet this method is even more effective. First take a match and press it against the metal surface to be tested. Keeping your fingers as far away as possible, light the first match with a second match… The sulfur is extremely hot as it combusts and it will certainly combine with pure silver when ignited in this fashion. It will not, however, mark nickel, steel, or chrome or any other shiny metal the way it marks silver (a black stain). Again this dark metal is silver sulfide and you can’t wipe it off with your finger–it must be cleaned off the metal with another agent. It’s important to note that both of these tests will not harm the metal and can be easily cleaned away.
A word of caution. Beware of labels that describe types of silver, for example, nickel silver contains no actual silver. It’s just a name for a specific nickel copper alloy. Names like “Mexican Silver”, “German Silver,” “Indian Silver,” “Montana Silver,” and even, believe it or not, the word “silver” all by itself do not actually guarantee any silver content. “German Silver” is another name for the alloy of copper, nickel and zinc (it was a derogatory term in the 1800s), and today this blend is called Nickel Silver. Despite the name, Nickel Silver contains no silver.