Most coins are minted perfectly… but sometimes the U.S. Mint makes shocking mistakes. These are called “mule coins” — coins struck with mismatched dies (designs from two different coins). 
While most errors are minor, true mules are mega-rarities worth tens of thousands to over $100,000 at auction. Here are the rarest U.S. mules ever discovered and how to identify them.
The $50K–$138K Mule Club
1959-D Lincoln Wheat Cent (The “Forbidden Transition”)
What Makes It Special:
Obverse: Normal 1959 Lincoln Memorial design
Reverse: 1958 Wheat ears (shouldn’t exist in 1959!)
Suspected Mintage: Only 3–5 coins known
Last Sale: $50,000 (VG grade, private sale)
Diagnostic Check:
- Weight: 3.11g (not 2.5g like modern zinc cents)
- Mint Mark: Genuine 1959-D style
1993-D Penny/Dime Mule ($51,750 Legend)
The Error:
Obverse: Roosevelt dime design
Reverse: Lincoln Memorial cent
Struck on copper-plated zinc (cent planchet)
Last Sale: $51,750 (2008, Legend Auctions)
Only 1 confirmed specimen exists.
Key Detail: Weighs 2.5g (not 2.27g like a true dime).
1999-P Memorial/Quarter Mule ($138K Record Holder)
Why It’s Unique:
Obverse: Lincoln cent portrait
Reverse: Washington quarter design
Mint Mark: None (Philadelphia issue)
Auction Record: $138,000 (Heritage, 2022)
Only 2 examples are confirmed, both graded MS63 (PCGS).
Mule Coin Market Breakdown
| Coin | Known Examples | Last Recorded Sale |
|---|---|---|
| 1959-D Wheat Cent | 3–5 | $50,000 (2023) |
| 1993 Penny/Dime Mule | 1 | $51,750 (2008) |
| 1999 Cent/Quarter Mule | 2 | $138,000 (2022) |
Investment Tip: Registry collectors often pay 20% premiums for newly discovered mules.
How to Spot Fake Mule Coins
Because mule coins are so valuable, counterfeits are common. Here’s how to test authenticity:
Weight Test – Use a precision scale (0.01g).
Edge Check – Cents = smooth edges, dimes = reeded edges.
Mint Mark Verification – Must match known authentic styles.
Red Flags of Fakes:
A 1999 mule with a “P” mint mark (should have none).
Wrong metal color (silver-looking cents are suspicious).
Casting seams or uneven rims.
Key Takeaways
Mule coins are accidental hybrids created by mismatched dies.
Only a handful are known, with values ranging from $50,000 to $138,000+.
Always authenticate through PCGS or NGC before buying or selling.
Final Word: If you ever find a coin that looks “wrong,” don’t dismiss it! You could be holding one of the most valuable mint mistakes in U.S. history. 
