Sonja sent us this picture of her spiffy Vermont quarter dollar. It is unusual, just as Sonja described.
I believe this is a 'Die Adjustment' error, which can carry some value, especially in older coins. See below.
In the minting process coin blanks, called planchets, are fed between two striking surfaces called dies. The dies contain the pattern of the coin, and they come down so hard on the planchet that they press the pattern into the metal and a coin is born. Modern minting machines produce dozens, or in some cases, hundreds of coins per minute. They are 'modern marvels.'
But even marvels need to be adjusted. When the mint workers set up a machine for a production run of coins, they adjust the amount of striking pressure between the dies so the coins come out just right. The pressure can not be too weak so the pattern is mushy, and it can not be too strong so that the dies break. During the adjustment period some coins are produced with mushy, or almost invisibile, patterns. It seems that Sonja has nabbed one of these.
Almost always mint workers gather up the coins struck during the adjustment period and destroy them. Once in a while, an adjustment error gets through and is soon gobbled up by an avid error coin collector. It is the demand from such collectors that give error coins their value.
Mike Byers of mikebyers.com is a recognized expert in the area of error coins. In his book 'World's Greatest Mint Errors,' Mike lists the catalog values of coins like Sonja's. Here are some of the values Mike assigns to US coins that are in a condition like Sonja's example:
Old Lincoln cents, before 1959: $200
Lincoln cents after 1958: $50
Jefferson nickels: $75
Old dimes and quarters, before 1965: $400
Dimes and quarters 1964 to 1999: $100
State quarters: $75
Old Kennedy half dollars, before 1965: $500
Kennedy half dollars after 1964: $200
These are catalog values. Use our Terminology page to understand the term 'catalog value.' It is probably different than you think!