Identifying Silver
MODERN COMMODITY PROSPECTING: AVOIDING FAKES AND KEEPING IT REAL
Silver is a soft, semi-white, opaque metal. Its color changes when exposed to air as black silver oxide forms and tarnishes the metal's surface. Silver in its pure form is soft, malleable and susceptible to distortion, so it is commonly mixed with other metal(s) to improve its hardness and durability. Although any metal can technically constitute the minority portion of the silver alloy, copper is most commonly used because it does not affect the color of the dominant silver. Sterling silver consists of 92.5% silver and 7.5% copper (or other metal.) Britannia silver contains at least 95% pure silver. Electrum, a gold and silver alloy, contains between 20 and 25% silver. Note that products marked "nickel silver" and other such hybrids do not contain any silver.
The identification methods outlined below refer to sterling silver.
1. Mark. Reputable sterling silver sources will stamp a mark into the metal to denote its precious contents. The mark will read either "sterling silver," "sterling," "ster," or ".925". Note, however, that antique silver from early eras may very well contain such a mark. It is feasible, also, that a dealer of ill repute could stamp a fraudulent mark into a non-silver piece.
2. Feel. Silver rates between 2.5 and 3.0 on Mohs' hardness scale. Touch the piece in question. Sterling silver has a softer, warmer feel than stainless steel or nickel.
3. Magnetism. A magnet is a piece of iron with a particular ordering of atoms which attracts other iron-containing objects. As such, the magnetism test is effective in determining if an object is not silver. If the magnet sticks to the piece, then it's probably either stainless steel (iron and carbon) or a nickel alloy (often nickel and iron.) The magnetism test is also a good way to determine if something is pure silver or silver plate as if silver is plated over nickel, it will still be magnetic. Understand, however, that material like aluminum, which exhibits a silver-gray metallic luster, will not attract a magnet; therefore, the magnetism test will not determine if an object is silver, only if it is not silver.
Some jewelry clasps made out of sterling silver, like slide clasps, may contain strong stainless steel springs which attracts magnets so if you use this method to test sterling silver findings, be sure to take this into account. Test on the clasp what looks like a good, solid piece of sterling silver to determine its authenticity.
4. Trust. Trusting the source of the silver goes miles in easing one's mind as to the compositional veracity of the product. I recently purchased a set of silver metallic clasps from a back alley jewelry dealer at more than 75% below the going rate of the metal. The merchant assured me they were sterling silver. The clasps didn't have a stamp mark; however, they were not magnetic. Could they be silver? Yes. Could they also be aluminum? Sure. I did not fully trust the source so i used those particular clasps for my test pieces.
5. Chemical Testing. Additional testing methods, while scientifically sound, potentially can or will damage your silver piece. Silver dissolves in nitric acid but do you really want to harm your piece by throwing it into a chemical bath just to verify its contents? Silver also tarnishes when exposed to hydrogen sulfide fumes. You could cause a chemical reaction on the metal's surface and then study its remnants but, again, you risk seriously damaging your piece. The latter also will not differentiate between silver and silver plate. I recommend, for the general savvy consumer, using methods 1 through 4 to investigate your commodities.
Good luck!