Key date
Encyclopedia
In coin collecting
, a key date refers to a date (or date and mint mark
combination) of a given coin series or set that is harder to obtain than other dates in the series. The next level of difficult to obtain coins in series are often referred to as semi-key dates or simply semi-keys.
For example, the 1909-S VDB is the key date in the Lincoln cent series. The 1914-D and 1931-S are considered semi-keys. In the United Kingdom
£1 coins
from 1988 are considered key date coins.
What makes a coin a "key" is somewhat more complicated because there are many issues that are easy to obtain in lower grades and very hard to find in higher ones. Collectors who want a series in near uncirculated condition may find some date/mint combinations extremely rare. This is because low mintage coins were frequently kept by collectors and saw little or no circulation, while common dates were rarely saved and typically became heavily worn. Another factor in making these conditional rarieties is that in certain years some or all of the mints did poor strikings of a coin. For example, finding the common 1919-D Walking Liberty half dollar
in well struck, near-perfect uncirculated condition, is an almost impossible challenge for even the collector of substantial means.
Professional and avid coin collectors will often not simply collect coins, but will specialize on a specific types of coin and then attempt to collect every coin in the series, i.e. one from every year that type of coin was minted with all variations, most notably mint mark, but can also be material; the coin was minted out of (some years, the same coin might be made out of two or even three different metal combinations, such as steel
, nickel
, iron
, gold
, bronze
or silver
) and even artistic differences or errors on the die that struck the coins and at the highest quality that can be found.
Often, locating a "key date" coin for a set is what stands between a complete set and just a collection. Once completed the entire set's value increases significantly.
Coin collecting
Coin collecting is the collecting or trading of coins or other forms of minted legal tender.Coins of interest to collectors often include those that circulated for only a brief time, coins with mint errors and especially beautiful or historically significant pieces. Coin collecting can be...
, a key date refers to a date (or date and mint mark
Mint mark
A mint mark is an inscription on a coin indicating the mint where the coin was produced.-History:Mint marks were first developed to locate a problem. If a coin was underweight, or overweight, the mint mark would immediately tell where the coin was minted, and the problem could be located and fixed...
combination) of a given coin series or set that is harder to obtain than other dates in the series. The next level of difficult to obtain coins in series are often referred to as semi-key dates or simply semi-keys.
For example, the 1909-S VDB is the key date in the Lincoln cent series. The 1914-D and 1931-S are considered semi-keys. In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
£1 coins
British One Pound coin
The circulating British one pound coin is minted from a nickel-brass alloy of approximately 70% copper, 24.5% zinc, and 5.5% nickel. The coin weighs 9.50 grams and has a diameter of 22.50 millimetres...
from 1988 are considered key date coins.
What makes a coin a "key" is somewhat more complicated because there are many issues that are easy to obtain in lower grades and very hard to find in higher ones. Collectors who want a series in near uncirculated condition may find some date/mint combinations extremely rare. This is because low mintage coins were frequently kept by collectors and saw little or no circulation, while common dates were rarely saved and typically became heavily worn. Another factor in making these conditional rarieties is that in certain years some or all of the mints did poor strikings of a coin. For example, finding the common 1919-D Walking Liberty half dollar
Walking Liberty Half Dollar
The Walking Liberty half dollar was a silver 50-cent piece or half dollar coin issued by the United States Mint from 1916 to 1947; it was designed by Adolph A. Weinman....
in well struck, near-perfect uncirculated condition, is an almost impossible challenge for even the collector of substantial means.
Professional and avid coin collectors will often not simply collect coins, but will specialize on a specific types of coin and then attempt to collect every coin in the series, i.e. one from every year that type of coin was minted with all variations, most notably mint mark, but can also be material; the coin was minted out of (some years, the same coin might be made out of two or even three different metal combinations, such as steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
, nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
, iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
, gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
, bronze
Bronze
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...
or silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
) and even artistic differences or errors on the die that struck the coins and at the highest quality that can be found.
Often, locating a "key date" coin for a set is what stands between a complete set and just a collection. Once completed the entire set's value increases significantly.
Partial List of Key Date U.S. Coins
- 1877 Indian Head Indian Head Cent
- 1909-S Indian Head Cent
- 1909-S VDB Lincoln Cent
- 1909-S Lincoln Cent
- 1914-D Lincoln Cent
- 1885 Liberty Nickel
- 1886 Liberty Nickel
- 1912-S Liberty Nickel
- 1913-S Type II Buffalo Nickel
- 1916-D Mercury Dime
- 1921-D Mercury Dime
- 1916 Standing Liberty Quarter
- 1932-D Washington Quarter
- 1932-S Washington Quarter
- 1916-S Walking Liberty Half Dollar
- 1921-D Walking Liberty Half Dollar
- 1893-S Morgan Dollar
- 1895 Morgan Dollar (known only in proof)
- 1921 Peace Dollar
- 1928 Peace Dollar