Silver is one of the world's most useful metals as well as one of the world's most valuable metals. 

Typically, sterling silver consists of 92.5 percent silver and 7.5 percent copper or other alloy. This makes it more suitable for wearable jewelry as 100% silver would be much too soft, would bend and easily show marks. 

The standard practice of adding 7.5% alloy makes your silver jewelry strong and long lasting.