The value of a collectible coin is based on a number of major factors. The most important of these are rarity and condition, but demand also plays a major factor. The more demand there is for a rare coin, the greater the prices it can command at auction. The most valuable coins can be worth millions of dollars.
1794 Flowing Hair Dollar
The 1794 Flowing Hair dollar coin is the most expensive coin ever purchased. In 2010, a 1794 Flowing Hair dollar was sold to the Cardinal Collection Education Foundation for $7.85 million dollars. The Flowing Hair dollar was the first federal dollar coin. Issued in 1794 and 1795, it was struck from silver with a small amount of copper. The obverse shows a bust of Liberty with long hair, while the reverse shows an eagle surrounded by a wreath.
Anglo-Saxon Gold Mancus
Finds of historical coins can be as valuable as all but the rarest collectibles. In 2006, the British Museum acquired an early-9th-century gold coin for £357,832, or approximately $586,000. The coin, minted in the name of King Coenwulf of Mercia, was discovered in Bedfordshire in 2001 by a metal detector enthusiast out walking with his dog. It is one of only a handful of Anglo-Saxon gold coins. Silver coins, although still rare, are much more common.
1933 Double Eagle
The rarity of a coin is sometimes based on its age. In other cases, a coin can be rare simply because of a quirk of history. This is the case with the 1933 $20 gold double eagle. This coin was released only shortly before the U.S. discontinued its federal gold standard. As a result, the coin was never circulated and most were destroyed. The surviving examples are therefore extremely rare. A 1933 double eagle was sold in 2002 for $7.6 million.
1943 Copper-alloy Penny
Some coins gain extra value because of mistakes or imperfections in their minting. One of the most famous of these is the 1943 copper-alloy penny. During the Second World War, U.S. pennies were struck in steel as a result of copper shortages. However, a small number of 1943 pennies were accidentally struck using leftover copper-alloy coin blanks. A 1943 copper cent sold for $1.7 million in 2010. Because of this coin's high value, it is often counterfeited.
Dr James Holloway has been writing about games, geek culture and whisky since 1995. A former editor of "Archaeological Review from Cambridge," he has also written for Fortean Times, Fantasy Flight Games and The Unspeakable Oath. A graduate of Cambridge University, Holloway runs the blog Gonzo History Gaming.