A blank coin (technically it is called a planchet if it has an upraised rim on it) is worth a few dollars, perhaps $2 to $4 if it's clad, more if it's silver. The Sacajawea, Presidential, and Native American Dollar coins all use the same type of planchet and these coins are worth anywhere from $12 to $15. Larger coins, for example, the Eisenhower dollar, usually sell for more. A penny blank will sell for between $2 and $3. A larger coin, like the Eisenhower dollar, or sell for between $20 and $30.
The Cause of Blank Coins
If your blank coin has a reeded edge on it, you're dealing with something entirely different. Most likely, someone ground off the obverse and reverse from the coin, or filed off the devices and polished the surface, because of the way the U.S. Mint makes coins, it is impossible for a planchet to be blank and still have reeded edges since the reeded edges are created at the same instant the coin is struck.
However, coins with the lettered edge such as the Presidential dollars or the Native American dollars have the edge lettering applied at the mint in a separate process. Therefore it is possible for a blank coin to avoid the striking process in the coining press and still have the edge lettering applied to it.
In other words, there is a round piece of metal inside the coining press with the hole machined into the center which is the exact size of the coin. For plain edge coins, the whole is smooth. For reeded edge coins, the whole has the vertical grooves machined into it which will impart the reeding on the coin when it is struck.
However, Presidential and Native American Dollar coins have a lettered edge. The lettering on the edge of these coins is added to the coin in a separate process after the coin is struck. There have been several blank Presidential and Native American Dollar coins that were never struck but have a letter to the edge. They are worth up to $100 a piece because they are very rare. Once again, beware of coins that have been altered by an unscrupulous person grinding off the details on the obverse and reverse side of the coin.
Almost Blank Coins
Some known coin striking issues can result in an almost blank planchet with reeded edges. If you see a faint, but the very blurry or weak impression on the planchet, it might be a die adjustment strike, which is worth $20 to $40 depending on the type of coin and depth of strike. Before a coin press is put into full operations, a mechanic at the mint must adjust the press to strike the coin properly. A few test strikes are done to see if the coin dies are too far apart. If they are, it leaves a faint image of the coin on the blank.
Another possibility for almost blank coins is a strike-through error, where something got in between the dies and the planchet surface, such as cloth or grease, when the coin was struck thereby obscuring or obliterating the devices (or parts of them.) The value of these varies based on the degree of obstruction and eye appeal and can run from $2 to $40 depending on what it was struck through.
Blank Coins With No Rims
If your blank coin doesn't even have the upraised rim yet, it's technically a coin blank. If it is made of silver, it is almost impossible to authenticate, but if it's clad, an expert on error coins could authenticate it, in which case (if authentic) it's worth maybe $50 or more. Keep in mind that a genuine coin blank will have a rough, perhaps sharp edge, and the blank may be off-color or grainy looking, depending on what part of the coin blank processing phase it was in when it left the mint. Beware of nice, shiny looking coin blanks with no upraised rim and a smooth edge. These usually just counterfeit blanks made to deceive vending machines.
Get Expert Advice About Your Blank Coin
In all matters of this sort, it's best to get your blank coin looked at by an expert. You can find a local PNG Coin Dealer, or send the specimen to a specialist in minting errors for an opinion. As a third option, if you can post a photo in a coin collecting forum and describe it very carefully there, and perhaps we can provide some additional information.
Finally, before you send your blank coin to third-party grading service, make sure it will be worth the charge that you will pay. It will cost you approximately $15 to $20 to have your coin authenticated and encapsulated at a grading service. A blank penny is only worth $2 to $3 and will not be cost-effective have it authenticated. On the other hand, an Eisenhower dollar will be well worth the cost of authentication.
Edited by: James Bucki