Sterling silver and silver plating appear similar to the untrained eye, but they are actually very different materials. Sterling silver is an alloy that contains 92.5 per cent pure silver. Since it has such a high silver content, it is valuable. Silver plating, on the other hand, is a thin layer of pure silver applied over some other kind of metal. Plating has no intrinsic value; once used as plating, silver cannot be recovered without significant and costly effort.
Look for markings on your silver object. You may need a magnifying glass if your object is small. Markings will be on the bottom of hollow objects like vases and candlesticks. For flatware and jewellery, they should be on the back side.
Use the markings to determine if your piece is sterling silver. Markings that say "sterling" or "925" indicate that the object is sterling. "EPC" and "EPNS" indicate silver plating. Not all pieces will be marked according to these standards, and some won't be marked at all. If you cannot determine if your piece is sterling by the markings, move on to step three.
Examine the edges of your metal object to determine if there is a base layer of metal showing through. If there is an obvious delineation between a top layer and a base layer, your piece is plated. If you can't tell, move on to step four.
Perform a nitric acid test on the object to know for certain whether it is sterling. Wear gloves to protect your hands from the acid. Find a discreet spot on your object and file through the plating or lacquer. Drop a small amount on nitric acid on the exposed metal. If the spot turns green or brown, your object is silver plated or a low-quality silver alloy. If it becomes cream coloured, it is sterling.
You can take the object to a jeweller or silversmith to get a professional opinion of its silver content. Sometimes, trademarks will be stamped onto silver objects along will the metal identifying marks. You can figure out who made the piece based on these marks. There are books on trademarks available in your local library.
Nitric acid is corrosive and toxic. Use extreme caution when performing a nitric acid test on silver. Filing silver to test it with nitric acid will result in permanent damage to the object. Therefore, you should only use this test when absolutely necessary.