In 1976, a small number of Bicentennial Quarters were mistakenly struck on 40% silver planchets intended for proof coinage. These error coins are highly sought after by collectors due to their rarity and unique composition.
Double die errors occur when the die used to strike the coin exhibits doubling in certain elements of the design. The 1976 Bicentennial Quarter is known to have double die varieties, particularly on the obverse side, which can command high prices in the collector market.
Similar to the silver planchet error, some Bicentennial Quarters were mistakenly struck on planchets intended for nickels. These off-metal errors are rare and highly desirable to collectors.
While the majority of Bicentennial Quarters were struck in copper-nickel clad composition, there are a few known examples of business strike quarters struck in 40% silver. These coins were not intended for circulation and are extremely scarce.
Mint marks indicate where a coin was minted, and their absence can be the result of various minting errors. Bicentennial Quarters struck at the Philadelphia Mint without a mint mark are rare and can command significant premiums from collectors.