How can you tell a 1983 quarter is worth 15000?

A 1983 quarter is worth $15,000 if it is a rare error coin, specifically the 1983 "No S" proof quarter, which was mistakenly struck without the mint mark. Authenticating its rarity requires verification from a reputable grading service, which will assess its condition and confirm its status as an error coin. Standard 1983 quarters without this error are only worth their face value. Collectors and dealers typically look for specific characteristics and minting details to determine the coin's value.