Most pennies from 1943 were made of zinc-coated steel due to the shortage of copper during World War II. However, a few were mistakenly struck in copper. These rare copper pennies can fetch significant sums at auction.
In 1955, a rare error occurred during the minting process, resulting in a doubling of the date and inscriptions on the Lincoln penny. This error is highly sought after by collectors.
In 1972, the design of the Eisenhower Dollar was modified, resulting in two distinct types. The Type 2 variety, featuring a stronger relief on the obverse, is rarer and more valuable than the Type 1.
In 1982, the Philadelphia Mint accidentally omitted the mint mark on a small number of Roosevelt dimes. These error coins are highly prized by collectors.
In 1992, the spacing between the "A" and "M" in "AMERICA" on the reverse of the Lincoln penny was inadvertently reduced, creating a variety known as the "Close AM" variety. This error is rare and commands a premium.
Some Wisconsin state quarters minted in 2004 feature an extra leaf on the ear of corn on the reverse side. This error occurred due to a die break and is highly sought after by collectors.
In 2005, a small number of Jefferson nickels were struck with a die gouge that resembled a spear or spearhead running through the bison on the reverse side. These error coins are rare and prized by collectors.