Gold filled is an actual layer of gold-pressure bonded to another metal. Gold filled is not to be confused with gold plating as filled literally has 100% more gold than gold plating. Gold filled is much more valuable and tarnish resistant. It does not flake off, rub off or turn colors. As a matter of fact, anyone who can wear gold can wear gold filled without worries of any allergic reaction to the jewelry. Gold filled jewelry is an economical alternative to solid gold!
Sterling silver is often characterized as pure silver, when in fact it is a silver alloy. Pure silver, also called fine silver, is defined as 99.9% pure silver, but is too soft for most uses. Sterling silver contains 92.5% silver, with the remaining 7.5% being another metal, most often copper. The addition of the less costly metal - often called a base metal - serves to harden the resulting alloy so that the metal can be cast into shapes that it will retain with use.