Examining Your Jewelry
Locate any identifying marks on your jewelry. These markings will be etched into the metal. If the jewelry has a clasp then the marks are probably on the back of the clasp. The jewelry might also have a small metal tag etched with marks hanging from the end. Lastly, search the largest parts of the jewelry. If your jewelry doesn't have any markings at all it's probably not a precious metal. EXPERT TIP Edward Lewand Edward Lewand Graduate Gemologist & Accredited Appraiser Edward Lewand is a Graduate Gemologist & Accredited Appraiser with over 36 years of experience in the jewelry industry. He completed his residency in graduate gemology at the G.I.A. in 1979, New York and now specializes in Fine, Antique and Estate Jewelry, consultations and expert witness work. He is a Certified Appraiser of the Appraiser Association of America (AAA) and an Accredited Senior Appraiser (ASA) of the American Society of Appraisers In Gems and Jewelry. Edward Lewand Edward Lewand Graduate Gemologist & Accredited Appraiser Examine the color and weight of the piece, as well. If you have a chance to compare platinum and silver side-to-side, it's easy to distinguish the differences between them. Platinum is much denser than silver, so it will have more heft to it. Also, platinum isn't really white—it's actually a gray color.
Look for marks indicating silver jewelry. Some coins and jewelry will have a stamp with the numbers “999." This indicates that the jewelry is made of pure silver. If you see a stamp with the numbers “925” followed or preceded by the letter “S," you have sterling silver. Sterling silver is 92.5% pure silver that's mixed with another metal alloy, usually copper. Pure silver jewelry is rare as pure silver is soft and easily damaged.
Find any marks indicating platinum jewelry. Platinum is a very rare and expensive metal. Therefore, all platinum jewelry will be marked to show authenticity. Look for the words “Platinum," “PLAT," or “PT” followed or preceded by the numbers “950” or “999." These numbers refer to the purity of the platinum, with “999” as the most pure. For example, an authentic piece of platinum jewelry might have a stamp reading “PLAT999."
Run a magnet over the jewelry. Most pure precious metals aren't magnetic, so if you place a magnet near the jewelry, you shouldn't see any movement. However, if your platinum jewelry is reacting to a magnet, don't panic. Pure platinum is a soft metal, so alloys are added to strengthen the finish. Cobalt, which is quite hard, is becoming popular as a platinum alloy. Because cobalt is slightly magnetic, some platinum jewelry may react to a magnet. Platinum/cobalt alloys will usually be stamped as PLAT, Pt950, or possibly Pt950/Co. The most common alloy used to harden sterling silver is copper, which is not magnetic. If you have a piece of sterling silver jewelry with a .925 stamp that's attracted to a magnet, see a reputable jeweler to verify its authenticity.
Using an Acid Scratch Testing Kit
Use an acid testing kit on hard-to-verify jewelry. If you can't find any identifying stamps and you're unsure about the origin of the jewelry, use a testing kit to find out what the jewelry is made of. Purchase an acid testing kit from an online retailer or jewelry supply store. This kit will include a sanding stone and several bottled acids. Buy a kit that can test for both silver and platinum. The bottle labels will indicate which metal they are used to test for. If the kit doesn't include gloves, buy some separately. If you get any acid on your hands you will burn your skin.
Rub the jewelry against the stone. Lay out the black slate stone on an even surface. Gently rub the jewelry against the stone in a back-and-forth motion to create a line. Draw 2 or 3 lines on the stone or one for each testing acid you'll use. For example, if you're testing for platinum, silver, and gold, you'll draw 3 lines. Choose an inconspicuous part of the jewelry to rub against the stone. The stone will scratch and damage a small section of the jewelry. Lay a towel down underneath the stone to protect your work surface from scratches.
Drop the acids on the different metal lines. Select an acid test from your kit and carefully drop a small amount of acid onto one of the drawn lines. Make sure that you don't mix the different acids together or you'll affect your results. Most tests have acids specifically for silver. However, you can also use an 18-karat gold testing acid to identify pure or sterling silver. Always wear gloves while handling acid. EXPERT TIP Edward Lewand Edward Lewand Graduate Gemologist & Accredited Appraiser Edward Lewand is a Graduate Gemologist & Accredited Appraiser with over 36 years of experience in the jewelry industry. He completed his residency in graduate gemology at the G.I.A. in 1979, New York and now specializes in Fine, Antique and Estate Jewelry, consultations and expert witness work. He is a Certified Appraiser of the Appraiser Association of America (AAA) and an Accredited Senior Appraiser (ASA) of the American Society of Appraisers In Gems and Jewelry. Edward Lewand Edward Lewand Graduate Gemologist & Accredited Appraiser Our Expert Agrees: When you're testing for platinum, you scrape a little piece of the jewelry on a stone, then you drop nitric hydrochloric acid on it. If the line stays, it's platinum. If it dissolves, it's not.
Observe the reaction of the acid. These reactions can take anywhere from a second to a minute. If the line completely dissolves, the test fails. For example, if you drop the Platinum acid test on a line and the line dissolves, the jewelry isn't platinum. However, if your line doesn't dissolve, the metal is pure. If you use the 18-karat gold acid test to test on silver, the line will turn a milky white color. This will indicate that your jewelry is pure or sterling silver. If you doubt your results, test the jewelry again to be sure.
Using a Testing Solution Directly on Silver
Use a silver testing solution on large, hardy pieces of jewelry. Avoid using this acid on delicately decorated jewelry. The acid will corrode any part of the surface that it touches. If you purchased an acid scratch testing kit, use the silver testing solution included. Otherwise, purchase the silver testing solution online or from a jewelry supply store.
Test the jewelry. Drop a small amount of the silver testing solution onto the metal. Choose a hidden area of the jewelry to test. For example, if you're testing a large cuff bracelet, drop some acid on the inside of the bracelet. Alternatively, if you're testing a flat, chunky necklace, drop acid on the back of one of the necklace sections. Wear gloves to protect your hands and work over a towel to protect your workspace. Don't drop acid on clasps or other important sections. The acid may damage any smaller workings in the jewelry.
Observe the reaction. The acid will appear dark brown or clear at first and then turn into a different color. The new color will indicate the purity of the metal. For example, if the liquid turns dark or bright red, the metal is at least 99% pure silver. If the solution turns white, the metal is 92.5% silver, or sterling silver. If it turns a bluish green color, it's copper or another lesser metal.
Clean the acid from your jewelry. Wipe off the acid with a clean cloth and throw it away. Rinse the jewelry under cold water to remove any residual acid. Use a sieve or plug up your sink to avoid losing your jewelry down the drain. Allow the jewelry to completely air dry before wearing it again.
Testing Jewelry with Hydrogen Peroxide
Submerge the jewelry in hydrogen peroxide. First, fill a glass bowl or cup with hydrogen peroxide. Next, drop the jewelry into the bowl. The jewelry should be completely submerged in the liquid. If it's not, add more hydrogen peroxide. Hydrogen peroxide can be found at most grocery stores.
Look for a reaction. Platinum is a strong catalyst for hydrogen peroxide. If the metal is real platinum, the hydrogen peroxide will begin to bubble almost immediately. Silver is a weaker catalyst. If you don't see any bubbles immediately, allow the metal to sit in the liquid for about a minute and look for small bubbles forming around the jewelry. Hydrogen peroxide won't corrode or damage your jewelry.
Rinse the jewelry well. Rinse the jewelry under cool water to remove the hydrogen peroxide. Plug up your sink or use a sieve while washing to avoid losing your jewelry down the drain. Allow the jewelry to completely air dry before wearing it again.
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