US Uniface (One Side Blank) Coins (Minting error)
US Uniface (One Side Blank) Coins (Minting error)

Check the amazing coin in our primary picture (to the left). It is clearly a US Indian Head Cent, but one side is missing. This is an error coin produced at the US Mint in error. The coin has been authenticated, graded, and encapsulated by NGC, the Numismatic Guarantee Company. The coin is currently at auction by Sullivan Numismatics, a well-respected dealer in error coins. We will not know the selling price until the auction ends, but it will probably be several hundred US dollars. CoinQuest thanks Sullivan for use of their coin image.

Uniface coins are almost impossible to evaluate without an in-person inspection. Once professionally evaluated, they should be encapsulated and annotated with the reason for the uniface. These coins can be quite valuable, up to hundreds of US dollars (sometimes more), but they can also be worth zero. The deciding factors are (1) whether or not the error occurred at the mint, and (2) what minting processed caused the error. There are six basic categories. The letters (A), (B), ... (E) refer to our figure to the right.

  1. Normal uniface pieces: minted with one side blank on purpose, (A) in the picture, normal value
  2. Machined pieces: ground down or otherwise altered after minting, not shown on this page, worth zero or bullion only
  3. Trial strikes: coins made before actual production, (B) or possibly (C), very valuable, $100 to $1000 US dollars
  4. Die cap errors: a complicated minting process explained below, possibly (C) or (D) in the picture, valuable, $25 to $300
  5. Two planchet errors: another minting process, possibly (C) or (D), valuable, $25 to $300
  6. Forgeries: fake coins, (E) in the picture, low value

If the uniface coin is a trial strike, die cap error, or two planchet error, it has strong collector value. If it is a normal coin, it has the value of that coin. Finally, a machined coin or a forgery has little or no value.

Trial strikes are done at the mint using one die, or hard metal piece used to imprint the pattern into the coin, and one planchet, or coin blank. If done under carefully controlled conditions, trial struck coins can look like (B) in our picture. With less control, trial strikes can look like (C). But another possibility for (C) is that the planchet got stuck on the die during striking. In this case, the stuck planchet is called a die cap and die caps are valuable minting errors when they escape from the mint's quality control department.

Die caps can have patterns on each side, or can be uniface when another planchet erroneously enters the minting machine. Further, planchets that are struck by a die which has a die cap are also error coins, and they can be uniface.

In summary, to find the value of your uniface coin you must ascertain how it was produced. This often takes a professional numismatist. Seek one out and show your coin to him or her. Two of our favorite professionals in this area are:

- Jon Sullivan
- Mike Byers

Coin: 20187 , Genre: Errors
Requested by: Chas, Sat, 24-Oct-2015 12:38:53 GMT
Answered by: Paul, Sat, 24-Oct-2015 20:36:33 GMT
Last review by CoinQuest: Sun, 25-Feb-2018 02:18:19 GMT
Requester description: Thai Satang coin from 1957, but one side is completely smooth with no evidence of ever having anything on it.
Tags: uniface one error ones erors errors thai thailand satang


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