Oxidation is a prime cause for silver to change colors, tarnish or appear coppery. Oxygen in its pure form is quite corrosive, especially to metals. The small amount of oxygen in the air we breathe every day can eventually begin to take its toll on our favorite silver jewelry pieces such as bracelets. Oxidation is the product of interaction between the molecules of oxygen in the air and the metal of the bracelet. The process of oxidation depends on the quantity of oxygen molecules present. When there are many oxygen molecules present, the rate of oxidation will be higher than if there are fewer oxygen molecules present. This process really takes place, though, on a molecular level, and what you can see is the product of oxygen causing free radicals on the surface to break free. You can try using silver polish to help reduce the oxidation process, but unfortunately there is very little you can do to stop the effects of oxidation on silver jewelry. You will have to use silver polish on a regular basis to keep your silver bracelets looking new and clean. Also try storing your silver jewelry in an airtight container, which will prevent the jewelry from oxidizing when you are not wearing it.
Another cause for silver bracelets to appear coppery is if they are not pure silver. Many times silver jewelry will be an alloy--a compound metal formed from combining two or more types of metal. In this case silver is combined with copper to create an alloy and the resulting effect is silver jewelry that is not pure. This can result in the silver giving off a coppery appearance after use and time.
Sometimes jewelry that appears silver is nothing more than silver or rhodium plating. Many different types of metal like steel or copper can be covered with a thin layer of silver. The result gives the jewelry a silver appearance when in fact the bulk of the piece is made from some other type of metal. If you have a piece of jewelry that is beginning to appear copper, this could be the case. Wear and tear on silver jewelry, especially bracelets, which are constantly in contact with the skin and rubbing against it, will cause the silver plating to wear. This will reveal the copper underneath.