Why does silver tarnish?

Many people are confused as to why some silver appears to tarnish more quickly or more deeply than other silver items.
Silver tarnish is actually a chemical reaction between silver and sulphur compounds. There are sulphur compounds in the atmosphere because of car and industrial pollution, but most people don't realise that there are sulphur compounds in many of the foods we eat.

Quite often pieces of jewellery such as silver chains are thought to be of poor quality because the owner finds that they tarnish quickly. Usually, this same owner will have problems with all their silver jewellery and may give up wearing it altogether.

Well, it has nothing to do with the quality of the silver jewellery! Pure silver, sterling silver and any other form of silver product will tarnish if it is exposed to sulphur. It's no different to steel rusting. Steel plus water equals rust. Silver plus sulphur equals tarnish.

Back to why food is a factor in tarnishing. Eating sulphur rich foods such as eggs, garlic, cabbage, even broccoli and asparagus can promote tarnishing of silver charms and chains you are wearing. The sulphur compounds in these foods are present in your perspiration and come into contact with your jewellery. People who sweat excessively are very often the ones "who can't wear silver."

Environmental factors also make silver tarnish more quickly, a humid climate and high levels of UV radiation both speed the tarnishing process. Living or working in industrial areas is also going to make any jewellery your wear tarnish more rapidly.
An effective, but expensive way to prevent or greatly reduce the tarnishing process is to have your silver jewellery rhodium plated. Avoiding wearing your jewellery while playing sports or doing other physical work will also help in keeping tarnish to a minimum.