- Use a magnifying glass to inspect the surface of the silver for stamps. If you see a 920 stamp, the piece is 92.5% silver, 900 means 90% silver, and 800 is 80% silver.
- Hold a magnet against the silver to see if it sticks. If it does, it's not real silver.
- Place an ice cube on the silver. If it melts immediately, it's not real silver.
- Apply a drop of bleach to the silver and watch for a reaction. If it tarnishes or blackens right away, it's real silver.
Authentication Stamp
Look for a stamp, engraving, or marking on the surface. Items advertised as silver and sold internationally have stamps that state the silver content. If there's no stamp on your silver piece, be leery.
Interpret stamps like 925, 900, or 800 as the percentage of silver. Look at the silver piece with a magnifying glass. International sellers of silver will stamp silver as 925, 900, or 800. Read these numbers to figure out the percentage of fine silver in the piece. 925 means that the piece is 92.5 percent silver (also known as sterling silver). A stamp of 900 or 800 means the piece is 90 percent or 80 percent silver, which is often called "coin" silver.
Check for letters like "STER" and "IS" on the silver. "STER" stands for sterling, which means the silver content is 92.5%. "IS" stands for "international silver," which means the piece is made with real silver. "IS" without a number stamp could mean the silver percentage is low, or that you have a silver-plated object. To see if the item is silver-plated or pure, try the acid test and the magnet test.
Magnet Test
Place a magnet close to the silver to see if it sticks. Use a strong magnet, such as the rare-earth magnet made out of neodymium. Silver is paramagnetic and exhibits only weak magnetic effects. If your magnet sticks strongly to the piece, it has a ferromagnetic core made with a cheaper metal and isn't pure silver. There are a few metals that don't stick to a magnet that can look like silver. Do the magnetic test in conjunction with another test to make sure the core is not another metal.
Tilt a silver bar to a 45-degree angle to see if the magnet slides down slowly. Turn one of your silver bars at a 45-degree angle and slide the magnet down it. If it's real silver, the magnet should slide slowly down the face of the bar. If the silver is fake, the magnet won't move. The magnet slides down slowly because silver is paramagnetic and the rare earth magnet induces electric eddy currents which act as an electromagnet. This creates a braking effect that slows the descent of the magnet.
Ice Cube Test
Grab some fresh ice for this test. Keep the ice in the freezer until you need it for the test. While it might not seem like ice and silver go together, silver has the highest thermal conductivity of any common metal or alloy (though copper is right behind). This test works well with coins and bars, but it's tough to do on silver jewelry.
Place a piece of ice on the silver and see if it melts quickly. If the silver is real, the ice will begin to melt immediately, as if it's sitting on something hot, rather than something that's just room temperature. This is because silver has very high heat conductivity. It can help to place another ice cube on a different room-temperature surface so you can see the different in melting times.
Sound Test
Perform a sound test on a silver coin. Silver makes a really lovely bell-like ringing sound when you tap on it, especially if you tap on it with another form of metal. If you want to try this out before tapping on your questionable silver, find a United States quarter made before 1965. These were made of 90% silver (US quarters made after 1965 are made of a copper-nickel alloy). The older quarter will emit a high-pitched, clear, ringing tone, while a newer quarter will just make a dull thump of a sound.
Drop the coin on a tabletop and listen for a high-pitched ringing sound. Hold the coin 6 in (15 cm) above a flat surface and drop it. If the coin makes a sound like a ringing bell, you have a real silver coin in your hand. If it sounds dull, the silver is most likely mixed with other metals.
Acid Test
Perform a chemical test analysis on the item. Use chemical analysis if there's no stamp signifying it is silver on your piece. Put on a pair of gloves first since you'll be using a corrosive acid to test the piece for purity. These sorts of acids burn skin. Note that this method has the potential to slightly damage your silver item. If you suspect you have a high-value item, you might be better off trying to determine the silver content using one of the other methods.
Buy a silver acid test kit. You can purchase these tests online or at jewelry stores. Silver acid tests are great for pure silver, but if you think your piece is silver-plated, use a small jeweler's file to make a mark and reveal what's under the plating.
Find an inconspicuous place on the silver and make a small scratch. This scratch is necessary so the acid can get to the underlying metal on silver-plated items. Scratch the piece using a metal file and use a fair amount of pressure so that you can get beyond any silver plating layer. If you don’t want to scratch your piece, use a black stone plate. These usually come with the silver testing kit, or you can buy one. Rub your silver on the surface of the black stone so it leaves a thick and relatively large deposit on the stone. Aim for a line that is ⁄2 to 1 in (1.3 to 2.5 cm) thick.
Apply a drop of acid to the scratched surface only. If the acid touches any area of the piece that isn't scratched, it will affect the polished look of the piece. If you're using a black stone, add a drop of the acid on the line you made with the stone. Alternatively, use a drop of vinegar (which is highly acidic) on the scratched piece. If it's real silver, the surface won't get tarnished. If the silver is fake, it will tarnish.
Analyze the scratched surface with the acid on it. Analyze the color that appears as the acid sinks into the piece. Be sure to follow the instructions and color scale of your specific silver testing kit. In general, the color scale is as follows: Bright Red: Fine Silver Darker Red: 925 Silver Brown: 800 Silver Green: 500 Silver Yellow: Lead or Tin Dark brown: Brass Blue: Nickel
Bleach Test
Put a drop of bleach on your silver item. Silver tarnishes extremely quickly when exposed to a powerful oxidizing agent such as common bleach.
Watch to see if the silver tarnishes or has no reaction. If it rapidly tarnishes and turns black, then the item is real silver. Note that silver-plated items will pass this test. You can easily clean your tarnished silver with toothpaste, baking soda, or silver polish.
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