About .925 silver
Composition
.925 sterling silver is an alloy of silver containing 92.5% pure silver and 7.5% other metals, usually copper. Fine silver (99.9% pure) is generally too soft for making functional objects. Sterling silver (.925) is usually mixed with copper to give it strength while preserving the malleability, making it ideal for making jewellery.
Sometimes other metals are used instead of copper to improve various properties of the alloy. Some of the advantages of these other alloys include reduction in casting porosity and also increased tarnish resistance.
Silver Care
Sterling silver can tarnish over time but with the right care it can retain its original shine and colour and last a lifetime. The best way to care for your silver is to polish it regularly with a silver polishing cloth. These are inexpensive and widely available. They are ideal for light tarnishing and keep your silver beautifully shiny. Silver that has not been cleaned for a while can be restored by using silver cleaning liquid, then washing, rinsing and drying it. Some people prefer to use natural products instead such as white vinegar or lemon juice.
Careful storage is also important as it will help to prevent tarnishing. Keeping your silver in a small anti-tarnishing bag or placing a small silica gel bag in your jewellery box will protect your silver by absorbing moisture from the air, maintaining a dry environment.