To accurately grade copper coins, you must be able to describe the color of the copper. Over time the brilliant orange/red color of a freshly minted copper coin, such as a Lincoln cent, will diminish and fade to a deep chocolate brown color. As this degradation of color occurs, there are varying degrees in which both red and brown colors will exist simultaneously on the surface of the coin. This color designation only applies to uncirculated copper coins. All circulated copper coins are assumed to be "brown."

Additionally, depending upon the environment where you store your copper coins, the surface of the copper may turn different colors. These toned coins can be beautiful or ugly. Some copper coins may take on an iridescent golden red. Others may turn deep red with hints of blue and indigo. These beautiful tone colors usually happen over long-term storage in less than optimal coin holders. However, these beautifully toned coins are highly prized by collectors, and they will pay a premium.

Although copper coins can tone into a variety of brilliant colors, be careful of fake coins before you buy them. This is not to say the coins themselves are fake, but there are "coin doctors" that can use a variety of chemistry and physical actions to turn ordinary copper coins into brilliant colors. A professional numismatist can tell the difference between a naturally toned coin and one that has been "doctored." These artificially toned coins are considered damaged and almost worthless to a serious collector.

Other coins may turn dark green or have splotchy black areas. Improperly storing your coins will also cause this ugly toning. Coin collectors shun these ugly coins, and they will not carry the value of a bright orange or beautifully iridescent toned coin. However, collectors of ancient coins and Colonial coins realize that some of these coins may not have been stored in optimal conditions. Therefore, some of them may be acceptable to be placed into a coin collection.

Be careful when purchasing toned coins. It is easy for coin doctors to use chemicals to replicate beautifully toned coins. However, an expert numismatist will be able to tell if the beautiful toning is natural or artificial. Artificially toned coins are considered damaged and will reduce the value of the coin.

Accurately describing the color of your copper coins will help you build a better collection.