Perhaps you have bought a piece of silver online from a dodgy site, or your friend gave you a piece she found. Maybe you just want to check out some family heirlooms that you're not totally sure are real. Whatever your reason, you'll need to know how to test your silver. Silver is a versatile chemical element. Sterling silver is 92.5 percent silver and 7.5 percent other metals, primarily copper. It is harder than pure silver. Pure silver is soft and often called "fine silver." Products often can be mistaken as silver if they are silver plated (merely covered with a thin layer of fine silver). Here are steps to begin testing your silver.
1. Look for a stamp. Items advertised as silver and sold internationally should be stamped based on the silver content. If there is no stamp, be leery. It may be still be pure silver, but created in a country that doesn't require stamping. Then, evaluate the international silver stamp rating. Look at the silver piece with a magnifying glass. International sellers of silver will stamp silver as 925, 900 or 800. These numbers indicate the percentage of fine silver in the piece. 925 means that the piece is 92.5 percent silver. A stamp of 900 or 800 means the piece is 90 percent or 80 percent silver, and is often called "coin" silver.
2. Test with a magnet. In particular, 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 and is not silver. Keep in mind that there are a few other metals that do not stick to a magnet and can be made to look like silver. It is better to perform the magnetic test in conjunction with another test to make sure the core is not another metal. If you are testing silver bars, there is another way you can use a magnet to see if your silver is real or not. Try the sliding test. Angle one of your silver bars so that it is at a 45 degree angle. Slide the magnet down it. The magnet should slide slowly down the face of the bar. This may seem counter intuitive, but silver is paramagnetic and the rare earth magnet induces electric eddy currents in the silver which act as an electromagnet to create a braking effect that slows the descent of the magnet.
3. Have some ice on hand. Keep it 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 will be harder to perform on silver jewelry. Place your piece of ice directly on the silver. Do not take your eyes off of it. The ice will begin to melt immediately, as if it has been placed on something hot, rather than as if it was placed on something that was just room temperature.
4. Try the ring test with any coin. Silver makes a really lovely bell-like ringing sound when it is tapped on, particularly when it is tapped on 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 while US quarters made later than 1964 are made of a copper-nickel alloy. The older quarter will give a high-pitched, clear ringing tone, while the newer quarters will give a dull thump of a sound. You can also perform the test by dropping your own coin on a flat surface from about six inches above it. If it makes a sound like a bell ringing, you have a real silver coin in your hand. If it's dull, the silver is, most likely, mixed with other metals.
5. Perform a chemical test analysis on the item. Use a chemical analysis if there's no stamp signifying it is silver on your piece. Put on a pair of gloves. You will be using a corrosive acid to test the piece for purity. These sort 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 listed here. Buy a silver acid test. You can purchase it at jewelry stores. Silver acid tests are great for pure silver, but if you think your piece is silver plated, you will have to use a small jeweler's file to make a mark, revealing what might be under the plating. Find an inconspicuous place on the item in question and make a small scratch on the silver piece. This is necessary to get to the underlying metal to test it with acid. Scratch the piece using a metal file. Scratch the surface enough so that you can get beyond any silver plating layer. If you don’t want to scratch your piece, or potentially leave a mark from the acid, use a black stone plate. These are generally provided with a silver testing kit, or will be sold in the same store. Rub your silver on the surface of the black stone so that it leaves a thick and relatively large deposit on the stone. Aim for a line that is one to one-half inch 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 chose to use a black stone, add a drop of the acid on the line that you created on your stone. Analyze the scratched surface with the acid on it. You will have to 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 test. 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
6. Silver tarnishes extremely quickly when exposed to a powerful oxidizing agent such as common bleach. Simply put a drop of bleach on your item. Watch for tarnishing or no reaction. If it rapidly tarnishes and turns black, then the item is silver. Note that silver plated items will pass this test.
Remember!
*If performing the chemical test to determine silver quality, use a pair of gloves, as the nitric acid is extremely corrosive.
*Flush your skin if it comes into direct contact with the nitric acid. After rinsing your skin well, apply sodium bicarbonate or baking soda to the area of skin that the nitric acid touched.
*Try to buy your silver from credible sources such as quality jewelers.
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