Coin Toning and Eye Appeal By Ron Drzewucki – Modern Coin Wholesale …..
Once it leaves the Mint, few things add value to a coin. But of those things, attractive natural coin toning arguably adds the most.
What is “ coin toning ”?
The word “toning” can describe both the coloration of a coin (what you see) and the chemical process that produced the color (what you don’t see). This is what is called coin toning. Since I buy and sell coins–and write about buying and selling coins–I’ll tend to use the first sense of the word, but it’s important to start with a basic understanding of the chemistry at work.
Coins, being made of various metallic elements, are composed of atoms and molecules like everything else in the world. And these atoms and molecules like to interact with other molecules and atoms. It’s a bit difficult for atoms and molecules in the center of a coin to interact with anything, so most of the activity occurs on the metal surface.
Another name for the process is oxidation. Or patina. Or corrosion. Technically, they’re all correct. And while “patina” sounds pretty, “corrosion” most definitely does not. Maybe that’s why people can have such strong opinions about it, both for and against.
At any rate, metal ions on the surface of a coin react with chemicals in the environment to create a thin layer of a new substance on top of the coin. The interaction of light as it reflects off of both the new material and the original coin surface results in the colorful patterns we call coin toning.
It’s the same as a soap bubble.
What does it look like?
Like much else in numismatics, toning can be a negative or a positive. The appearance of a coin, for better or for worse, is known as “eye appeal”. While eye appeal can take into account all manner of details that affect a coin’s appearance, the term is usually used to refer to those traits that do NOT contribute to the grade or condition of a coin.
Toning is probably the most obvious aspect of eye appeal.
And not all toned coins can be judged by the same standards; different coins are capable of different colors of toning. One shouldn’t expect rainbow toning on a Lincoln cent, and one shouldn’t look for the blue-green patina of the Statue of Liberty on a Morgan dollar.
Copper coins tend to come red, brown, and various combinations thereof.
Coins with high nickel content tend to color up in dull greys.
The gold in gold coins is nonreactive (meaning it’s the exception to the whole “atoms and molecules interacting with other molecules and atoms” shebang), and that’s part of its timeless appeal, but gold is too soft to make durable coinage by itself so all gold coins have at least a small percentage of other metals mixed in. To the extent that a gold coin exhibits toning, it is because of this. Alloys of copper are a common choice so the varieties of copper toning can be seen in spots on gold coinage.
But most of the magic happens on silver coins. Ranging from a highly-undesirable black to russet golden browns to iridescent blues, violets and yellows, compounds of silver run the gamut.
What is “Artificial Toning”?
One aspect of toning that inspires controversy is the distinction between “natural” and “artificial” toning. It seems strange to debate whether a chemical is “natural” or “artificial”, but what these terms refer to is whether or not the toning was produced as a by-product of collecting or with the intent to make a buck.
Which, if you’re aware of how “natural” toning is produced, also seems a little strange.
If you’re not, then read on.
“Natural” toning is the result of a coin’s interaction with its environment. Oftentimes, the manner in which coins are collected, stored, or displayed creates the toning. In the past, U.S. Mint canvas bags, coin boards, coin envelopes, paper rolls and other paper products contained a fair amount of sulfur. Silver and copper sulfides are responsible for most of the toning you’ve probably seen. Other variables, including moisture, heat, duration of contact and intensity of contact also come into play.
Because of these factors, a naturally-toned coin is like a snowflake–no two are exactly alike.
“Artificial” toning, on the other hand, is toning-on-demand. Coin doctors are known to use chemical baths or dips, focused heat and electricity to “manufacture” toning on a coin. Since the chemistry of toning is well-established, coin doctors are capable of making what, to the untrained eye, looks like amazing, almost miraculous color.
Many highly-skilled and highly-knowledgeable people have written volumes on how to avoid artificial toning. They’ve done it better than I can do here, today. But a good rule of thumb is this: if you collect toned coins, it’s probably a good idea to trust the third party graders and buy slabbed coins. Reputable TPGs won’t slab toned coinage if there’s even a whiff of doubt about its origins.
But, just to complicate things, the hobby has a habit of changing its mind as to what is acceptable or not acceptable treatment of a coin. It wasn’t too long ago that the Mint itself baked gold coins according to a finely tuned formula in order to produce what was then a desirable “roasted” tone.