Using the touchstone, magnetic or sound method are ways to test jewelry for silver. A chemical analysis or testing the hardness and malleability of the metal are two more ways to test for silver.
The touchstone method involves testing silver's purity by rubbing the item against a wedge of thick slate. By comparing the resulting stripe, the test shows whether the item is silver or another metal. For the magnetic method, a person places the item by a magnet to check if the item is magnetized. Since silver is not magnetic, it will not attract. An item that does not attract is still possibly made from another metal, but silver-plated.
The sound method requires the tester to make a clean strike against the metal. Real silver has a distinct ringing sound, proving the item is fake if there is no sound.
Jewellers typically use the chemical analysis method. They do this by swabbing nitric acid and potassium dichromate on the metal. An item that is 90 to 99 percent silver causes the swab to leave a deep red residue on the testing paper. Jewellers swab a hidden part of the piece as the grey residue remains after the test.
Since silver is a soft and malleable metal, easily bending an item is a sign of real silver. Silver objects are also easier to file in comparison to other metals.