Fine Silver in its natural state, 999/1000 pure, is too soft an element for practical jewelry. To make it workable, an alloy such as copper is added. Here are the main silver alloys:
Sterling Silver: A mixture of 92.5 % pure silver (925 parts) and 7.5 % metal alloy.
Silver Plating: Also known as silver plated or silver coated. A base metal, usually nickel silver or brass, is coated with a layer of pure silver by a process called electroplating.
Vermeil: Sterling silver electroplated with at least 100 millionths of an inch of karat gold
German Silver or Nickel Silver: A silver-white alloy consisting of copper, zinc and nickel.
Coin Silver: 90% (900 parts) pure silver and 10% (100 parts) metal alloy. A process of melting down coins done in the 19th century, and mostly discarded today.