Sterling silver tarnishes because it reacts with sulfur compounds in the air, producing silver sulfide, a black, tarnish-like substance on the surface of the silver. This process is known as tarnishing. Tarnishing is a natural process that occurs with most types of silver and is not a sign of poor quality.
There are several factors that can contribute to tarnishing, including humidity, exposure to chemicals, and the presence of certain foods or drinks. For example, silver can tarnish faster in a humid environment or if it comes into contact with substances like sulfur, rubber, or certain types of wood. Silver also reacts with certain foods and drinks, such as eggs, onions, and salad dressing, which can cause it to tarnish faster.
To prevent tarnishing, it is recommended to store silver in a dry place, away from sources of sulfur and other chemicals. Silver should also be stored in an airtight container, such as a tarnish-resistant bag or a jewelry box with a tight-fitting lid. Silver can also be cleaned and polished regularly to remove tarnish and restore its shine.