The examples and perspective in this article may not represent a worldwide view of the subject.(January 2022)
Proof coinage refers to special early samples of a coin issue, historically made for checking the dies (as in demonstrating that something is true) and for archival purposes. Nowadays proofs are often struck in greater numbers specially for coin collectors (numismatists).  Nearly all countries have issued proof coinage. 
Preparation of a proof striking usually involved polishing of the dies. They can usually be distinguished from normal circulation coins by their sharper rims and design, as well as much smoother "fields" – the blank areas not part of the coin's design.
The dies for making modern proof coins are often treated with chemicals to make certain parts of the design take on a frosted appearance, with the polished fields taking on a mirror finish. Several other methods have been used in the past to achieve this effect, including sand blasting the dies, and matte proofs. Proof coins of the early 19th century even appear to be scratched, but it was part of the production process. The term "proof" refers to the process by which the coins are made and not to the condition of the coin. Certification agencies can grade and assign numerical ratings for proof coins. A PR70 coin is the highest grade possible for a proof coin and indicates a perfect example, with PR69 and lower grades reflecting some deficiency in the strike, centering, details, or other aspect of the coin.
Most proof coins are double struck under higher pressure. This does not normally result in doubling that is readily observable, but does result in the devices being struck fully, resulting in intricate elements of the original die being present on the proof that may not be present in such detail on circulation strikes. After being struck, they are separately and individually handled, in contrast to normal coins which are thrown into bins.
The U.S. had largely stopped striking proof coins in 1916, although a few later specimens exist. From 1936 to 1942, proof coins could be ordered individually from the United States Mint. Beginning in 1950, customers could order proof coins only as complete sets.
From 1950 to 1955, proof sets were packaged in a box and each of the five coins was sealed in a cellophane bag. 1955 saw both the original "box" packaging and introduced the flat-pack, where the coins were sealed in cellophane and presented in an envelope. The flat-pack packaging continued through 1964, after which the coins were sealed in various styles of hard plasticized cases. (From 1965 to 1967 the production of proof sets was suspended and Special Mint Sets were made in their place. They were made at the San Francisco Assay Office but bore no "S" mintmark.)
Sets struck from 1936 to 1942 (1942 offered a five-coin and a six-coin version, the latter included the silver wartime nickel) and from 1950 to 1972 include the cent, nickel, dime, quarter, and half dollar. From 1973 through 1981 the dollar was also included, and also from 2000 on. The 1999–2008 proof sets also contain five different 50 State quarters. The 2004–2005 series also contain the two Lewis and Clark nickels. The 2007-2016 proof sets also include Presidential dollars. The 2010-2021 proof sets also contain America the Beautiful quarters, depicting different National Parks and Monuments. Proof sets issued in 2009 contain 18 coins – the most ever included – as that year featured four different reverses for the Lincoln Cent, six quarters issued under the District of Columbia and United States Territories quarters program, four Presidential and one Native American dollar struck that year, and the five cent, dime, and half dollar coins. Proof sets containing only 2009 cents, 50 State quarters, America the Beautiful quarters, Presidential dollars, and American Innovation dollars are also available.
The U.S. Mint has also released special proof sets, such as in 1976, when a proof set of three 40% silver-clad coins: the quarter, half-dollar and dollar coins depicting special reverses to commemorate the U.S. Bicentennial was issued. From 1971 to 1974, proof silver-clad Eisenhower dollars were issued in a plastic case contained in a brown wood-grain finish slipcase box, and are referred to as "Brown Ikes". Proof Susan B. Anthony dollars were struck in 1999. Although these proof dollars were sold separately and not included in the proof sets for that year, some third parties used the cases from other years to create 1999 proof sets that include the dollar, prompting the U.S. Mint to advise the public that these sets were not government-issued sets. A proof "Coin & Chronicles" set was issued for 2009, which included one each of the 4 different Lincoln Cent designs and a commemorative Lincoln Silver Dollar, presented in special packaging. Other sets, called "Prestige Proof" sets, also contain selected commemorative coins. These sets were sold from 1983 to 1997 (except 1985) at an additional premium. As Legacy Proof sets, the practice was resumed from 2005 to 2008.
Occasionally, there are errors which escape the Mint's inspection process, resulting in some very rare and expensive proof sets. This has happened at least seven times: 1968-S, 1970-S and 1975-S and in the 1983-S Prestige set, each with a dime that has no mint mark; a small number of 1971-S sets included a nickel without a mint mark; 1990-S saw both regular and Prestige sets which included a penny with no mint mark.
Not as rare (or as expensive) are proof sets issued with coin varieties that are less common than those found in other sets issued in the same year. These include the 1960 and 1970-S sets, both of which are found in either a "small date" or "large date" variety, which refers to the size and position of the date on the Lincoln cent. The 1979-S and 1981-S sets each come in either a "Type I" or a "Type II" version, where on all coins the "S" mint mark is either "filled" (also known as the "blob" mint mark) or "clear". 1964 has a design variation where the President's portrait on the Kennedy half-dollar has "accented hair". The design was modified early in the production (reputedly at the request of Jacqueline Kennedy) to give the hair a smoother appearance. This resulted in the "accented hair" variety being somewhat rarer and commanding a premium over the "regular" variety.
Since 1992 the mint has struck proof sets in both silver and base metal. Also, "Silver Premier" sets, featuring deluxe packaging, were offered from 1992 to 1998. U.S. commemorative and bullion platinum, palladium, gold, and silver coins are also often issued in both uncirculated and proof types, sometimes with different mint marks.
Starting in 1947 the U.S. mint began producing "mint sets", and because of the terms used there is some confusion over the difference between these and proof sets. These are uncirculated coins that have been specially packaged, and are generally neither as expensive nor as valuable as proofs. There are some exceptions, however. Those produced from 1947 to 1958 (none were made in 1950) were double sets packaged in cardboard holders and have good collector demand. Because mint sets contain specimens from each mint the precious metal value of the coins in a mint set could exceed the value of a proof set for common dates. Another exception is the 1996 mint set, which, in addition to specimens from the Philadelphia and Denver mints, contained a Roosevelt dime from the West Point mint (commemorating the 50th anniversary of the Roosevelt dime) and which was available only in this mint set. From 1965 to 1967 the mint did not sell proof or uncirculated coins, but only a hybrid product, "special mint sets", none of which are particularly valuable. From 2005 through 2010 the U.S. Mint used a special "satin finish" on the coins in its uncirculated sets, but in 2011 changed to a "brilliant finish" so that contact marks incurred during the normal production process would be less noticeable.
The Philadelphia and Denver mints also sold annual "souvenir sets" from their gift shops since 1973 (1972 for Denver). These are not mint sets and generally not of high collectable value, although the 1982 and 1983 sets are in demand, since no "official" mint sets were issued during those years. Sales of the souvenir sets ended in 1998 with the launch of the 50 State quarters. Finally, individual dealers have made unofficial "year sets", privately packaging all denominations of a certain date. The latter have no value beyond their individual coins. Members of the public should be careful to understand what products they are being offered, and that, until supplies are exhausted, current and previous mint and proof sets are available directly from the mint.
The quarter, short for quarter dollar, is a United States coin worth 25 cents, one-quarter of a dollar. The coin sports the profile of George Washington on its obverse, and after 1998 its reverse design has changed frequently. It has been produced on and off since 1796 and consistently since 1831.
Coins of the United States dollar were first minted in 1792. New coins have been produced annually and they make up a valuable aspect of the United States currency system. Today, circulating coins exist in denominations of 1¢, 5¢, 10¢, 25¢, 50¢, and $1.00. Also minted are bullion and commemorative coins. All of these are produced by the United States Mint. The coins are then sold to Federal Reserve Banks which in turn are responsible for putting coins into circulation and withdrawing them as demanded by the country's economy.
The United States Mint is a bureau of the Department of the Treasury responsible for producing coinage for the United States to conduct its trade and commerce, as well as controlling the movement of bullion. It does not produce paper money; that responsibility belongs to the Bureau of Engraving and Printing. The first United States Mint was created in Philadelphia in 1792, and soon joined by other centers, whose coins were identified by their own mint marks. There are currently four active coin-producing mints: Philadelphia, Denver, San Francisco, and West Point.
The United States Bicentennial coinage is a set of circulating commemorative coins, consisting of a quarter, half dollar and dollar struck by the United States Mint in 1975 and 1976. Regardless of when struck, each coin bears the double date 1776–1976 on the normal obverses for the Washington quarter, Kennedy half dollar and Eisenhower dollar. No coins dated 1975 of any of the three denominations were minted.
The Eisenhower dollar was a one-dollar coin issued by the United States Mint from 1971 to 1978; it was the first coin of that denomination issued by the Mint since the Peace dollar series ended in 1935. The coin depicts President Dwight D. Eisenhower on the obverse, and on the reverse a stylized image honoring the 1969 Apollo 11 Moon mission based on the mission patch designed by astronaut Michael Collins. Both sides were designed by Frank Gasparro. It is the only large-size U.S. dollar coin whose circulation strikes contained no silver.
The quarter, short for quarter dollar, is a Canadian coin worth 25 cents or one-fourth of a Canadian dollar. It is a small, circular coin of silver colour. According to the Royal Canadian Mint, the official name for the coin is the 25-cent piece, but in practice it is usually called a "quarter", much like its American counterpart. In French, it is called a caribou or trente sous. The coin is produced at the Royal Canadian Mint's facility in Winnipeg, Manitoba.
The Canadian five-cent coin, commonly called a nickel, is a coin worth five cents or one-twentieth of a Canadian dollar. It was patterned on the corresponding coin in the neighbouring United States. It became the smallest-valued coin in the currency upon the discontinuation of the penny in 2013. Due to inflation, the purchasing power of the nickel continues to drop and currently the coin represents less than 0.5% of the country's lowest minimum hourly wage.
The Kennedy half dollar, first minted in 1964, is a fifty-cent coin currently issued by the United States Mint. Intended as a memorial to the assassinated 35th president of the United States John F. Kennedy, it was authorized by Congress just over a month after his death. Use of existing works by Mint sculptors Gilroy Roberts and Frank Gasparro allowed dies to be prepared quickly, and striking of the new coins began in January 1964.
The West Point Mint is a U.S. Mint production and depository facility erected in 1937 near the U.S. Military Academy in West Point, New York, United States. As of 2019 the mint holds 22% of the United States' gold reserves, or approximately 54 million ounces. The mint at West Point is second only to the gold reserves held in secure storage at Fort Knox. Originally, the West Point Mint was called the West Point Bullion Depository. At one point it had the highest concentration of silver of any U.S. mint facility, and for 12 years produced circulating Lincoln cents. It has since minted mostly commemorative coins and stored gold.
This glossary of numismatics is a list of definitions of terms and concepts relevant to numismatics and coin collecting, as well as sub-fields and related disciplines, with concise explanations for the beginner or professional.
The coins of Canada are produced by the Royal Canadian Mint and denominated in Canadian dollars ($) and the subunit of dollars, cents (¢). An effigy of the reigning monarch always appears on the obverse of all coins. There are standard images which appear on the reverse, but there are also commemorative and numismatic issues with different images on the reverse.
The Jefferson nickel has been the five-cent coin struck by the United States Mint since 1938, when it replaced the Buffalo nickel. From 1938 until 2004, the copper-nickel coin's obverse featured a profile depiction of founding father and third U.S. President Thomas Jefferson by artist Felix Schlag; the obverse design used in 2005 was also in profile, though by Joe Fitzgerald. Since 2006 Jefferson's portrayal, newly designed by Jamie Franki, faces forward. The coin's reverse is still the Schlag original, although in 2004 and 2005 the piece bore commemorative designs.
The Washington quarter is the present quarter dollar or 25-cent piece issued by the United States Mint. The coin was first struck in 1932; the original version was designed by sculptor John Flanagan.
One of the most highly profitable aspects of the Royal Canadian Mint’s enterprise is in its Numismatic product line. The euphoria surrounding the year 2000 led to the birth of the Millennium 25-cent coin program. The numismatic line included proof quality coins sold individually or as a complete set. This level of excess would come to signify the coming decade. The number of numismatic releases would increase on an annual basis starting in 2003. Numismatic three cents, five cents, and ten cents would be introduced, along with numismatic three dollars and eight dollars. Luxury coins would not be immune to the dramatic increases that ensued. Coins with face values of 250, 300 and 350 dollars would be introduced by 2006.
Coin roll hunting is the hobby of searching and sorting coinage pulled from circulation for collectible coins. This is achieved through obtaining rolled coin, boxed coin, or bagged coin from banks and credit unions. A variant of this practice involves banknotes and is carried out in essentially the same fashion, normally to search for unusual serial numbers, star notes and misprints.
The America the Beautiful quarters were a series of 56 25-cent pieces (quarters) issued by the United States Mint, which began in 2010 and lasted until 2021. The obverse (front) of all the coins depicts George Washington in a modified version of the portrait used for the original 1932 Washington quarter. There were five new reverse (back) designs each year, each commemorating a national natural or historic site such as national parks, national historic site, or national forests – one from each state, the federal district, and each territory. The program was authorized by the America's Beautiful National Parks Quarter Dollar Coin Act of 2008 (Pub. L. 110–456 .
The United States Mint has released annual collections of coins most years since 1936.
The Apollo 11 50th Anniversary commemorative coins were issued by the United States Mint in 2019 to commemorate the 50th anniversary of the first crewed landing on the Moon by Apollo 11 astronauts Neil Armstrong and Buzz Aldrin. Consisting of a gold half eagle, two different sizes of silver dollars, and a copper-nickel clad half dollar, each of the four was issued in proof condition, with all but the larger silver dollar also issued in uncirculated. The gold coins were struck at the West Point Mint, the silver at the Philadelphia Mint and the base metal half dollars at the mints in Denver and San Francisco.
The United States Mint Proof Set, commonly known as the Proof Set in the United States, is a set of proof coins sold by the United States Mint. The proof set is popular with coin collectors as it is an affordable way to collect examples of United States coinage in proof condition.
The United States Uncirculated Coin Set, known as the Uncirculated Set or Mint Set in the United States, is an annual coin set sold by the United States Mint. The set is marketed towards coin collectors as a way to obtain circulation coins in mint condition.