Sterling silver is 92.5% silver and is sometimes referred to as pure silver. Sterling silver will tarnish over time but with care and regular cleaning can be restored to its good as new sparkling condition. The remaining 7.5% is usually copper but can be other metal and is used to give this precious metal strength and durability. Generally, the higher the silver content the brighter or whiter the metal but beware of antiquing effects that can make a piece of sterling silver jewellery or decorative silverware look dark. Silver which is 99.9% silver is too soft to be practical for most day to day uses. Do not use tissue or anything other than a jewellery cleaning cloth to polish your jewellery as unseen tiny hard fibers will scratch the surface.