Check for hallmarks or stamps such as 925, Sterling, or 999
Use a magnet; real silver is not magnetic
Rub with a soft white cloth; silver may leave a black tarnish mark
Apply a drop of nitric acid on a hidden spot; silver reacts differently than base metals
Use a silver testing acid kit according to the kit instructions
Test with a silver-specific electronic tester
Weigh the item and compare it to known silver density if size is known
Listen for a high, clear ring when lightly tapped
Look for tarnish that turns dark or black over time
Have it tested by a jeweler or precious metal dealer