Color toning can raise or lower coin value. When the effect occurs naturally, it can be incredibly beautiful, but may also be downright unattractive. As such, putting value on these coins can be challenging.

How Color Toning Occurs

Color toning is a phenomenon in which a coin will become discolored. It results from the presence of chemicals and oxygen which creates various toning levels depending on the metal properties. It is commonly seen in silver, nickel, gold and copper. It is a natural oxidation process that occurs slowly and can take decades or even centuries to appear. Typical colors which are seen in toned coins include orange or red for copper, rainbow colors for silver and yellow, red, orange or purple for gold.

Will Toning Increase Value?

It depends. No two coins will have the exact same color toning, and if they are already rare, their collection value can be substantial. Depending on beauty and rarity, a color toned coin can sell for tens of thousands more than standard issues. Coins which are lustrous and in mint condition will always carry a premium, but realistically, few coins which are over a hundred years old will be in this condition. If anything, color toning is a sign of authenticity, since every coin will go through the process sooner or later, unless it is being stored in a vacuum.

Watch Out For Coins That Are Discolored Artificially

Although color toning occurs naturally, there are some that do it artificially, a process that is referred to as coin doctoring. There are “recipes” online that teach people how to give their silver a tarnished look. The reason people do it is to boost the appearance of the coin in an effort to sell it at a higher price point, while concealing any imperfections the coin has.

However, doing this accomplishes the opposite; it dramatically devalues the coin. You should never buy them, as coin experts can immediately tell the difference between natural and artificial color toning and you will never be able to get a good deal for them.

What To Do If Your Coins Have Color Toning

If you notice that coins in your collection are undergoing color toning, don’t be alarmed. As stated previously, the process is completely natural and the coin will never disintegrate.  The best solution is to hold onto them. As long as the process occurred naturally they will maintain their value and it might actually go up. Should you decide to sell them it is probably a good idea to get them professionally apprised by either PCGS (Professional Coin Grading Service) or NGC (Numismatic Guaranty Corporation) if they already aren’t. The reason for doing so is that it verifies the coin has been professionally inspected and graded which confirms to potential buyers that the color toning is indeed natural rather than artificial. The same is true for purchasing toned coins; it is best to only buy those which have been professionally graded.