A U.S. quarter-dollar coin is valued according to its grade, rarity, liquidity and how much interest the coin can attract. The material from which the quarter is made may add to or detract from its value.
Coins are graded according to their appearance, color, luster, strike and preservation. While the practice is subjective, a classification system is in place.
The least valuable quarters are classified as Poor, Fair or Almost Good, while quarters of average value are Good, Very Good, Fine, Very Fine or Extremely Fine. The most valuable quarters are considered Almost Uncirculated, Uncirculated, and Brilliant Uncirculated. These titles accompany a numerical grading scale of 1 to 70.
The rarity of a quarter increases its value. Quarters with rare mint marks or dates, or those that are part of a limited series, are worth more money than commonly circulated quarters. Rarity impacts the amount of interest a quarter can attract from potential buyers. Both rarity and interest directly influence a quarter's liquidity – the time it would take to sell the coin to a collector or at an auction.
The material from which the quarter is made also impacts its value. Older quarters were cast from pure silver. This formula changed to 90 percent silver years later, and is now a mixture of copper and nickel. Due to the high and rising prices of silver, many old quarters are worth around $3 before even considering their grading, rarity, interest or liquidity.