Why does silver tarnish?
Silver is an amazing and beautiful precious metal, but the tarnishing that sometimes occurs on silver objects can be quite frustrating.
Silver tarnishes over time when it’s exposed to air. This tarnishing happens because of the sulphur-containing gases in our air. These gases discolour, darken and dull the surface of silver objects.
The sulphur-containing gas that tarnishes silver most often is hydrogen sulphide. This gas is created by the breakdown of organic materials, like the oil on our skin.
When combined with silver, hydrogen sulphide creates a layer of silver sulphide on the surface of a silver object. This process is a protection mechanism to protect the inner silver from further turning into silver sulphide. Tarnish on sterling silver also contains copper sulphide. Other silver tarnishing reactions come from sulphur dioxide and chlorine.
Silver tarnishing occurs quicker and heavier when there are higher concentrations of sulphur-containing gases in the air. In areas with a higher humidity, silver also tarnishes quicker since the humidity speeds up the tarnishing process.
Silver-plated jewellery and tarnishing
Tarnish on a silver-plated object can damage the object in a much more severe way than a solid silver jewel or object. There’s only a thin layer of silver on the surface of a silver-plated object. Polishing off tarnish on a silver-plated jewel might damage or even completely remove the silver-plating.