1. 1916-D Mercury Dime: This is one of the most sought-after dimes due to its low mintage of just 264,000. High-grade examples can fetch significant amounts, though not typically $90 million.
1894-S Barber Dime: Only 24 were minted, and fewer than 10 are known to exist today. The rarity and mystery surrounding these dimes make them extremely valuable.
1969-S Doubled Die Obverse Roosevelt Dime: This mint error features significant doubling on the date and is highly sought after by collectors.
Error Coins: Quarters with significant minting errors, such as double strikes or wrong planchet errors.
High-Grade Specimens: Coins in exceptionally high grades (MS67 or higher) are more valuable.
Special Compositions: Any quarter struck on a precious metal planchet by mistake or part of a special, limited run.