A coin valued at five cents was the first official coin of the United States (in 1792), but nickels did not appear in the U.S. until 1866. On May 16 of that year, Congress passed an act to usher in the new five-cent coin, made of 25 percent nickel and 75 percent copper.
Over the next seven years, the Mint produced nickels and silver half dimes, before phasing out the half dimes. There are four basic nickel designs: Shield, Liberty, Buffalo and the Jefferson, with only slight variations in early coins. The 2004-05 coins commemorated Lewis & Clark’s journey and the obverse of the coin — the side with the head, typically — got a makeover in 2006.
The value of coins varies by demand and is influenced by rarity and condition. In the U.S., two main organizations, the Professional Coin Grading Service (PCGS) and Numismatic Guaranty Corporation (NGC), evaluate coins using the Sheldon Scale to assign a numerical rating, from 1 to 70. Coins rated 60 or higher are referred to as "mint" state coins. Gem coins are rated 66 or higher, and they possess exemplary strike and luster and no noticeable abrasions.
You’re not likely to find one of the following 20 nickels under your couch cushions. But if you do, don’t spend it. They are worth a combined $15 million.