All About Coin Toning
What is Coin toning?
Coin toning is a chemical process that reacts on the surface metal of the coin. It changes the color through oxidation forming a thin layer of tarnish on the metal's surface. Coins with unusual toning colors or patterns tend to be of more worth amongst the coin collectors. Toning is most commonly found on silver coins but also found to a lesser extent on gold, copper, nickel, and other composition coins. Gold coins take on fine shades of toning as they get older. As the gold coins from the U.S. are composed of 10% copper, it can oxidize and result in the toning of the coin.
Susan L. Maltby, an experienced professional conservator who writes a quarterly column for Coin World on coin conservation and related subjects, explains: “Toning is the result of a complicated electrochemical process called corrosion. Whether you call the surface of a coin corroded, toned or tarnished, the process and the result are the same. Corrosion converts a small amount of the metal on the surface of a coin to a corrosion product. This corrosion process is irreversible.”
The patterns and intensity of toning can vary enormously. These chemical reactions happen naturally and can also be artificially generated. Coin doctors study the chemical process of toning in depth. Some of them are very good at artificially toning a coin in a matter of minutes that naturally takes more than a hundred years.
How Does It Happen?
Coin toning generally occurs naturally over time. It is due to the oxygen or sulfur reacting on the coin's metal. It is purely based on the environment in which the coin is. However, the toning process can be accelerated by the heat, moisture, and a variety of other chemicals in the environment. Few of the most harmful chemicals for coins can be found in coin holders or coin folders. Coins stacked in bags for a long time can develop crescent toning, where the toned coins were partially covered by one sitting off-center on top of it. This type of crescent toning occurs most commonly in Morgan dollars. In extreme cases, this toning can turn into corrosion and cause significant damage to the surface of the coins. In worst cases, these damages might also be permanent and can render the surface of the coin porous such that it looks like it was sandblasted.
Types Of Toning
Toning can come in many different colors and combinations. Silver coins tend to tone in striking colors. These colors range from bright blue to intense magenta, brilliant red to deep orange, and an array of shades from olive, green, and gold. Unfortunately, toning can also sometimes turn out ugly. The ugly shades occur in black or brown. These toning patterns may appear just on one side of the coin, just one area, or the entire coin surface. Different colors, combinations, and ways of toning can have changing effects on a coin's grade and value.
Natural vs. Artificial Toning
Coin toning happening naturally is a slow process that is completely based on environmental factors. In this, the chemicals in the environment affect the toning of these coins. Many of these coins are toned based on the way they are stored for a more extended period of time. A fine example of this is the natural toning that happened to a few Morgan dollar coins stored for over 100 years in canvas bags in the United States treasury vaults. The chemicals from the cotton canvas bags in which they were stored reacted slowly over time, bringing out beautifully rainbow-toned silver dollars. Other than this, few coin folders, albums, and paper envelopes that are not made out of archival quality can contain sulfur and acids that react to the coin's surface and bring out the pleasant rainbow toning. Sometimes it can also bring out an ugly shade of black or brown toning.
Coins are toned artificially through the use of certain chemicals. This is probably done to increase the value of a coin. However, artificial toning reduces the value of a coin when spotted. A few dishonest coin doctors can create an artificial rainbow toning on coins by using a variety of treatments and chemicals. The coin doctors also use toning to cover up imperfections or alterations on the coins. Only a professional coin dealer or a third-party grading company can detect this immediately.
Coins with natural toning are always almost preferable. But coins with intense artificial toning, for instance, altered American Silver Eagles, are sometimes sold as novelties.
The Toned Effect On Value
The impact of the coin's beauty on the eye determines its value. Toned coins usually have two conflicting perspectives. Some coin collectors admire the beautiful colors that a vividly toned coin can possess and are ready to pay over and beyond the actual value of an untoned graded coin. The more vivid the coin's color with its patterns, shades, and combinations, the higher its value. This way, low-value coins can become a rare collectible. On the other hand, a rare or scarce coin with beautiful toning and pattern can reach enormous value when sold.
There are other coin collectors who believe that the chemical process has actually damaged the coin's surface and avoid them altogether.
However, we suggest that whenever you purchase a toned coin paying a significant amount of money, make sure they are certified by a third-party grading service to affirm that the toning is natural and authentic. Avoid purchasing raw uncertified toned coins from online auction services.