Difference Between Silver and Sterling Silver

What is Sterling Silver?

Sterling Silver is 92.5% silver, hence its purity mark is 925, which is why you will often find it referred to as 925 Sterling Silver.

Why do we use Sterling Silver and not Silver? 

Well, the answer is that Silver is very soft and therefore not suitable for all jewellery.  In order to make it hard, it is combined with another metal, usually copper, as this doesn't discolour it.