A few steps to test if your jewellery are really sterling silver.
1. Look for a distinctive sterling silver seal. Precious metals are stamped with a seal, symbol or series of symbols indicating their type, purity and authenticity.
2. Determine if the object is magnetic. Like gold and platinum, silver is a non-ferrous metal, it is not magnetic. Place a powerful magnet on your object. If the magnet does not attract the object, it will be made of non-ferrous metal. To determine what type of non-ferrous metal your item contains, you may need to perform other tests. If the object sticks to the magnet, it does not contain sterling silver. It is more than likely that the object is made of polished stainless steel that has been modified to look like pure silver.
3. Do an ice test. Silver has the highest thermal conductivity among known metals, that is, it carries extremely fast heat. You can use this knowledge to determine if your object is made of silver. There are two ways in which the ice test can be performed. Place your object on a flat surface. Put one ice cube on it and another on your work surface. If the object is made of silver, the ice cube on the object will melt much faster than the one on the table.