One of the most often discussed issues when evaluating a rare coin is the effect that toning has on its grade, and ultimately its value. Generally, a dark, blackish or splotchy look is seen as unfavorable, while multicolored, rainbow toning in a crescent or target pattern is usually seen as favorable.
What is rainbow toning on coins?
“Rainbow” toning or patina is an optical effect caused by graduated layers of silver oxide on the surface of a coin. This is often seen on coins that have been in contact with a sulfur source (a great oxidizer) for a good number of years (usually 20 years or more).
Why are some Morgan silver dollars rainbow toned?
Toning Propensity of Metals When first minted, copper coins have a bright red color. Over time, the copper oxidizes and the coin’s color darkens to brown. Silver frequently reacts with sulfur to form rainbow toning – the Morgan dollars at the top of the article are examples of that process.
Does toning affect coin value?
Coin toning can intrinsically increase or decrease the value of coins. Natural coin toning can be quite beautiful. It can also be outrageously ugly. And because beauty is often times in the eye of the beholder, placing a value on a coin due to its toning can present problems.
What causes silver dollars to tone?
Toning occurs naturally over time. It is mostly the result of oxygen and/or sulfur reacting with the coin’s metal. The toning process can be accelerated by heat, moisture and a variety of chemicals in the environment. Silver coins tend to tone in the most vivid colors.
Are toned silver dollars worth more?
Morgan dollars are one of the most popular series of United States coins to collect with vivid toned colors. Naturally toned coins can bring a premium several times more than an untoned coin. Many of these silver coins toned as a result of the way they were stored for a long period of time.
Why are toned coins worth more?
The coin market for toned coins is hot. The more vivid the colors and the more variety of different hues on a coin will increase its value. This can make a seemingly common low-value coin a rare collectible. A rare or scarce coin that has beautiful toning on it can reach astronomical values when sold.
Why is my silver coin turning black?
Silver becomes black because of hydrogen sulfide (sulfur), a substance that occurs in the air. When silver comes into contact with it, a chemical reaction takes place and a black layer is formed. The oxidation of silver jewelry is a sign that it is really silver.
