You scored a silver chain at a yard sale but can't verify that your new treasure is a genuine jewelry find. The best way to authenticate it is to take it to a jeweler. Before you do, however, check for some marks that may show that it's real and reveal its value. All silver jewelry made in America and most of the world after 1848 should have a maker's mark visible at the clasp or along the chain.
Lay the chain on a soft cloth on a flat surface. Undo the clasp.
Move a magnet a few inches above and over the chain. If the chain is attracted to the chain, it is made of metal and is not silver.
Look at the chain, beginning at the clasp, with the magnifying glass. Look for the numbers 925 or a specific hallmark or maker's mark. You may see a name or an icon like a crown. If no mark is visible on the clasp, examine the chain carefully. If no mark is visible, the chain is probably not the real thing.
Drop a tiny drop of nitric acid on the chain. If the acid turns gray or silver, the necklace is genuine silver. If the acid turns green, the chain may only be silver-plated.