4 differences between naturally and artificially aged coins

Take a look at this picture. Can you determine which of the four Morgan dollars (minted in the United States from 1878 to 1904, as well as in 1921) the color is artificially changed, and which one by itself?

Are you giving up? All four coins naturally acquired their hue. The colors of these coins cover the entire rainbow palette, but experts are convinced that the hue has developed over time, rather than being artificially created. The question arises - if all coins with such a variety of colors and shades fall into the category of "naturally aged", then how collectors will be able to distinguish the copies "artificially aged"? This article lists the criteria that experienced coin collectors follow to help enthusiasts distinguish an artificial patina from a naturally aged piece. This is necessary to know, since the natural patina of a coin that is pleasing to the eye can multiply its value, while artificial patina can completely nullify its collectible value.

1. The chemistry of discoloration

Any article on coin aging begins by describing the chemical processes that contribute to it. At a basic level, a change in the color of a coin is the result of the chemical interaction of its surface with atmospheric elements (most often sulfur and oxygen). In the course of the reaction, a compound (patina) is formed on the surface of the coin, which has a color different from the metal of the coin.

Color change is a gradual process and usually takes years to complete - the most vividly naturally aged coins get their hue after decades of storage in conditions that favor discoloration. Conditions favorable for color change - an atmosphere of high humidity with the presence of sulfur (often these are paper envelopes or bank packages for money) - but the general rule is this: color change occurs in any case, unless the coin is isolated from the external environment in an airtight container.

Some personalities try to imitate the aging process of the coin, so that the aging effect manifests itself in a shorter period of time. These "chemists" or "handicrafts", as they are called in mockery, expose coins to sulfur in a humid hot environment in order to speed up the discoloration process and get copies that are not very different from those patinated in natural conditions. The range of methods described on the Internet is wide - many sources promise excellent results by baking a coin in a potato, boiling a specimen with eggs and other ridiculous methods. All methods of artificially changing color are frowned upon by serious coin collectors, and such coins are considered "problematic" as if they had been polished, sanded, or damaged. An artificially aged coin loses its collectible value and usually its price is determined by the weight of the metal from which it is minted. Third-party coin valuers refuse to give any numerical value to fake colored pieces, marking them on the accompanying label as fake discolored.

2. Predisposition of metals to discoloration

In order to distinguish artificially aged specimens from others, it is important to know the properties of the metals from which the coins are minted. Copper specimens change color differently than silver ones, while silver specimens change color differently than gold ones. Copper is the most reactive metal used in coinage, and therefore the most prone to discoloration. Newly minted copper coins are bright red in color. Over time, copper oxidizes and darkens. How long this process takes is a separate question, but most coins issued in the 19th and 20th centuries are now brown. Copper coins of the original color (RD - marked by experts on the weak), are worth more than brown (marked with BN), or mixed colors (marked by RB specialists). Copper can also become "rainbow" in color, but this is unlikely. Any copper or bronze coin should be judged with somewhat more skepticism, as it is very possible that the color of the specimen has naturally changed.

Silver coins are in second place after copper coins in terms of their ability to change color. Like copper, silver oxidizes and tarnishes over time. Silver often reacts with sulfur and produces a "rainbow effect". Nickel coins are less prone to discoloration than their silver and copper counterparts. Nickel itself is a fairly neutral metal and, oxidizing over time, becomes a dark gray color. But in an alloy with copper (like most modern American coins - 25% nickel and 75% copper), the reactivity increases slightly. "Rainbow color" is nothing new for copper-nickel coins, although such specimens should be looked at more closely than "rainbow-colored" copper or silver coins. Last but not least, gold and platinum are extremely inert metals. Gold, oxidizing, becomes orange and very rarely - red or crimson. Platinum does not change color at all. The "rainbow effect" on other metals was not noticed at all.

3. Artificially aged coins

Moving away from the topic of color change with metals, color combinations of artificially aged coins can be a wake-up call for a collector. As a rule, artificially patinated coins have more expressive colors - antiquity counterfeiting is by no means a delicate process. For such specimens, bright blue, bright crimson and red colors are very characteristic, and there is no smooth transition between colors (gradient). Naturally aged coins have a smooth flow of colors, as well as combinations of colors of the natural spectrum: flow of green to yellow, yellow to pink, pink to red, red to violet, violet to blue and blue to green. Coins with sharp transitions from one color to another should be looked at with great attention.

4. Naturally aged coins

Now take a look at the picture at the beginning of the article. In Morgan dollars, there are also blues and crimson shades, but lighter ones. What is important, the transfusion of colors on the surface of the coin is perceived softer with the naked eye. It should be noted that the coin that came out of the minting has a visible luster, while the artificially patinated Morgan dollar and the Franklin half dollar (minted in the USA from 1948 to 1963) from the previous section do not have such a luster. For issued coins, bright colors are relatively uncommon, so this is another suspicious sign. On issued coins, the color change is a darkening associated with metal oxidation rather than a "rainbow effect".