Error Coin Essentials: Identical Faces

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This article is sponsored by CAC Grading, the collectors’ choice, inspiring confidence through accurate and consistent coin grading.

Error Coin Essentials introduces the core concepts behind coins that didn’t come out quite right. These articles provide a practical foundation for collectors who want to understand how errors happen, how to identify them, and how to collect them. With strong collector demand and a wide variety of examples, error coins remain one of the hobby’s most engaging fields. 

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Even noncollectors are fascinated by genuine “two-headed” and “two-tailed” coins with identical faces. Apart from the possible exception of a two-headed 1859 Indian cent, all are assumed to be clandestine creations. Shown below is a quarter with a reverse design on each face. It’s one of two (or possibly three) double-reverse quarter mules that are universally accepted. (A mule is a coin struck by mismatched dies.)

How Identical Faces Occur

Like most coins with identical opposing designs, two anvil dies were employed. In most coining presses, the anvil die neck is longer than the hammer die neck. If a hammer die is placed in the anvil die assembly, its shorter neck will have difficulty elevating the planchet within reach of the normally situated hammer die. Thus, the coin will probably be weakly struck. An example of this is the two-headed 2000-P 5-cent coin featured in the June 26, 2017, issue of Coin World. Machining a longer die neck solves the problem but requires greater time and effort.

Other mint-sourced coins with identical faces are produced outside of a coining press. Coins bearing such “illicitly applied die impressions” (matching or otherwise) have many tells, including a weakly impressed design, multiple impressions, drastically misaligned designs, seriously damaged dies, odd forms of doubling, severe post-impression damage, and numerous other tip-offs (Coin World, November 16, 2020, and February 1, 2021).

Examples with Soft Details

Absolute certainty that a coin was struck by two matching dies inside a coin press requires a strong, clear die-struck design on each face. If one face has a mushy design, then other possibilities come into play.

Shown above is a two-tailed quarter in which one reverse design is mushy. Numismatic Guaranty Company (NGC) described it as “double struck with two reverse dies and indent.” In other words, the second strike was interpreted as an in-collar uniface strike (struck against an underlying or overlying planchet). The only way to confirm NGC’s interpretation is through the presence of non-matching die markers on each face (die scratches, die wear patterns, etc.). Unfortunately, die markers are usually erased in a uniface second strike. In their absence, one must consider other scenarios.

Pseudo-Mules

There are three basic ways to create a two-tailed or two-headed pseudo-mule in a press with a conventional die setup. Each method leaves the coin with a mushy, raised design on one face.

• Method 1: A newly struck coin flips over, landing above or below a planchet. A second strike flattens the die-struck design against the planchet, while the original raised design on the opposite face is completely erased and replaced. Complete erasure of the first-strike design is more likely if the second strike occurs outside the collar.
• Method 2: A planchet receives a uniface first strike. The coin flips over and is struck again, with its die-struck details flattened against the other uniface coin or a fresh planchet. The original featureless surface simultaneously receives a fresh, die-struck design.
• Method 3: A planchet is struck against a coin, leaving the former with a full, centered first-strike brockage (an incuse, mirror image). The brockage is then placed against a second planchet while facing the die from which its design is derived. The two discs are struck together, leaving the second coin with a die-struck design on one face and a matching counterbrockage (a distorted raised tertiary design) on the opposite face.

Other Possibilities

An even more complex chain of events may apply to the unique two-headed 1981-P quarter shown below. NGC correctly described it as a double-struck die cap, though it failed to note the presence of two raised obverse designs. The second, uniface strike failed to erase clash marks on the face carrying the flattened, expanded design. These clash marks do not match clash marks on the unobstructed die-struck face. Does this mean that this coin started out as a genuine two-headed mule? Not necessarily.

It’s possible that after a first strike—like those described in the three methods above—the various coins and planchets used in the fabrication process were moved over to a different press for the second strike.

Conclusion

For coins with identical faces, grading services only occasionally invoke pseudo-mule scenarios and never consider illicitly applied die impressions. Therefore, it’s up to the collector to apply a skeptical eye to any purported two-headed or two-tailed mule that presents an odd appearance.

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Mike Diamond has been collecting, researching, and writing about error coins since 1997.  He previously wrote a weekly column for Coin World  (“Collectors’ Clearinghouse”) that focused on minting errors and die varieties.  Prior to that, he was responsible for dozens of articles that appeared in CONECA’s specialty journal Errorscope.  He created and contributed most of the content found in The Error-Variety Ready Reference.  Over the past 28 years, he has discovered or described well over 100 new error types.

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