One thing that helps determine a collectible coin's value in the marketplace is its rarity. This is by far not the only factor that influences price, for a rare but undesirable coin will not have as much value as a more common coin in greater demand--but rarity does play a part. One way of approaching the issue of rarity is to consider rarity within a series. A series consists of all the variations in date, mint, and peculiarities of design, for a coin of particular denomination and type (such as the Flying Eagle cent). An 1856 Flying Eagle cent is far more rare than an 1857 cent. Consequently, a Flying Eagle from 1856 is worth more than 100 times as much as one from 1857. A coin may be rare because few of that type were minted in that year. Occasionally, a coin may be comparatively rare because a minor design change or error occurred during the year of its production, meaning that fewer coins with a particular variation (e.g., with or without the designer's initials) were produced. Coins of a particular grade may also be rare within a series, or even within a date and mint combination. Sometimes circulated coins from a particular date and mint combination will be comparatively abundant, but uncirculated or mint state coins of the same issuance will be extraordinarily rare. Rarity, by its nature, tends to make the market for a particular item less liquid, and more subject to wide price swings in the short term. Although rare coins can be quite valuable, buyers should always be aware that investing in rare coins involves inherent risk.
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