Adjustment marks
Marks made on a coinage blank to ensure consistency when used to become a coin.
Alteration
The act of adding or changing a date or mint mark outside of a mint, usually to create the appearance a coin is a rarity.
Annealing
Heating of coin blanks to soften them prior to being struck with coinage dies.
Artificial toning
Tarnish appearing on a coin caused by purposeful improper storage to create the surface colors now appearing on that coin.
Assay
A destructive test through which the purity of metal can be determined.
Bag marks
Detrimental marks on the surface of a coin caused by banging against other coins when stored in bags.
Bank note
A promissory note issued by a banking agency through which assets are pledged valued at the same amount as the note issued against those assets.
Beaded border
A border of dots around the edge of a coin.
Billon
An alloy of copper and silver also known as potin, but containing more than half copper.
Bit
A pie-shaped piece cut from a Spanish 8-real coin to make change.
Blank
The round metal disk, or planchet, specially cut in preparation for the coin images to be added to make a coin.
Bourse
The area of a coin show where dealers buy and sell coins.
Branch mint
A remote mint facility that aids coinage production centralized at the main mint.
Brockage
An error coin on which one side is struck correctly, however the other side is the incuse mirror image of this other side.
Bullion
Platinum, palladium, gold, or silver coins struck to a specific weight and purity and meant to be traded for their intrinsic value rather than for their legal tender face value. These coins do not command a premium above this precious metal value. They are a convenience, circumventing the need for assaying the metal when it is sold.
Burnishing
A minting process through which coinage surfaces are brightened.
Business strike
A coin made by mass production and intended to circulate as money. The majority of coins encountered in coin collections will be business strikes.
Cabinet friction
The rub a coin receives from movement while in storage in a coin collection.
Cameo
A coinage finish in which the main devices appear to be frosted or otherwise set apart from the background.
Carbon spots
Detrimental oxidation specks appearing on the surfaces of a coin.
Cartwheel luster
The surface brilliance of an uncirculated coin originating from when the coin was first produced. This brilliance disappears when a coin circulates or is cleaned.
Cast
Most coins are produced by being struck rather than cast. A cast coin can be identified either by its soapy surface appearance or by tiny casting bubbles visible under magnification.
Certificate of authenticity
Specially printed certificates may guarantee the coin or coin set being sold is genuine, but be aware there is no guarantee the certificate remains with the coin for which it was originally issued. Such certificates often include metal purity, weight, and other statistics, as well as a serial number specific to that set for which the certificate is being issued.
Chop marks
Small Chinese character marks made on silver coins by Chinese merchants to ensure the purity of the precious metal content of the coins.
Clad coinage
Coins containing copper-nickel rather than silver alloys. U.S. clad coinage began in 1965. U.S. half dollar coins of 1965 to 1970 contain a low grade of silver and are called silver-clad coins.
Clash marks
A ghost-like impression of the image of the opposite side of a coin may appear on the other side. This image is due to the coinage dies having clashed without a coinage blank being in place between them during production immediately prior to the striking of the coin depicting clash marks. These are popular with collectors.
Cleaning
A serious taboo in coin collecting, cleaning a coin usually ruins any collector value it may have.
Clipped
A coin with some metal shaved from the edge, yet still used in commerce as if it is still of the correct weight for the denomination.
Coin
A coined metal composition object identified as having been struck by a coin-issuing government authority, with a specific legal tender face value. Do not confuse coins with medals and tokens.
Coin board
A board, folder, or book with holes of a specific diameter drilled into each page for the coins. Coin boards are typically referred to as penny boards.
Coin cabinet
A wooden or plastic chest of drawers made with slots to display or collect coins.
Coin dealer
A person who works either full or part time buying and selling coins for a profit without first acquiring the coins for collecting purposes.
Collar
The device that holds the coinage blank, also ensuring the blank remains round once the coin images have been struck onto that blank.
Commemorative
A coin struck for a limited amount of time to mark a person, place, or event. Some commemorative coins circulate, while others were made especially for collectors.
Commercial grade
An optimistic grade assigned to a coin that likely is truly a grade lower by most accepted grading standards.
Contact marks
Detrimental marks appearing on a coin from contact with other coins.
Contemporary counterfeit
A fake coin or note produced during the period when the coins were being struck or the notes were being printed to deceive the public, rather than at a later date strictly to deceive collectors.
Copper-nickel
Also called cupro-nickel, this is a coin composition mix used widely on modern circulation coins.
Corrosion
Any form of rust or oxidation appearing on the surface of a coin.
Counterfeit
A replica of a coin made without proper authority and meant either to deceptively circulate or to be sold to collectors.
Countermark
A mark or several marks added to a coin after its initial issue either by a government or by a private individual.
Cud
Occurs when a break in the coinage die interrupts the appearance of the image.
Currency
Although this term technically encompasses all circulating money, it is usually used as a reference to bank notes.
Date
The date appearing on modern coins identifies the year in which the coin was produced. Most coins prior to 1500 lack dates. Some of these earlier coins can be dated through their design elements or by the regnal year of the reigning monarch expressed on these coins.
Debasement
Any time the precious metal purity of coins is decreased the coin is said to be debased.
Deep mirror prooflike (DMPL)
A coin with prooflike surfaces sufficient that a reflection of the person viewing the coin can be seen.
Denomination
The legal tender face value imprinted on a coin or bank note. Ideally coins chosen for a collection will be worth more than this face value.
Denticles
The small notches about the outer edge of the obverse or reverse of many coins at the rim. Also called dentils.
Device
The main design element or achievement on a specific side of a coin.
Die
The tool from which an image of a coin is impressed onto a blank or planchet. Many dies are usually involved in producing coins since dies wear out from use.
Die alignment
The relationship of the alignment between the obverse and reverse dies. Coin alignment is opposites while medal alignment is when both sides correspond exactly to the other.
Die break
When a coinage die begins to break during use, cracks appear on the die and are transferred to coins being struck.
Die crack
The cracks from the die break being transferred from the disintegrating die. These die cracks will appear on coins as raised rather than as incused lines.
Die rust
An incorrectly stored coinage die will eventually rust. When such rust is polished away to use the die, it leaves deep recesses in the die that will be transferred to coins struck from that die.
Die state
The amount of wear on a working coinage die will determine the quality of the detail appearing on coins struck from that die. A late die state struck coin will not have the sharp detail an early die state struck coin will exhibit.
Die variety
A variation from the normally anticipated design of a coin caused by something that altered the individual die from which the coin was struck. Varieties are very popular among coin collectors.
Ding
A small mark appearing on a coin due to the coin having bumped against something.
Dipped
A coin that has been cleaned, likely by dipping the coin into a liquid solution. Collectors do not consider dipped coins to be desirable.
DMPL (Deep mirror prooflike)
A coin with prooflike surfaces sufficient that a reflection of the person viewing the coin can be seen.
Doubled die
A coin struck from a coinage die on which some or all of the images are doubled. This is a more desirable doubling than is strike doubling, in which the coinage blank was struck more than once to achieve the doubling appearance.
Double struck
A coin that was struck more than once by a working coinage die will exhibit doubling, but this should not be confused with a doubled die error coin. Double struck coins are the result of a production problem.
Edge
The side of a coin, not to be confused with the rim, which is the outer edge of the obverse or reverse.
Electrotype
A duplicate of a coin created using electrolytic methods. Metal is deposited into a mold made from the host coin.
Engraver
The person who designs the coinage dies; known as a celator in ancient times.
Error coins
Coins displaying problems due to mistakes made during production.
Essay
Also called an essai, the term represents experimental pieces, pattern coins, transitional, and trial pieces.
Exergue
The small area at about six o'clock on a coin, usually separated from the balance of the coin design by a line, where the date, value, or country of origin may appear.
Eye appeal
The perception of a coin or bank note from the item's outward appearance. This can include toning, strike quality, centering, and other such factors, other than condition.
Face value
The denomination value appearing on a coin or a bank note.
Fantasy issue
A coin that was never officially struck, such as an 1868 U.S. large cent or a coin issued by the nonexistent nation of Sealand.
Field
The open surface of a coin on which there is no design.
Fineness
The purity of the precious metal of a coin, typically expressed in decimal form such as .916 fine rather than as 22 karat. A .916 fine coin has 91.6 percent of that metal in it.
Flip
A 2-by-2 inch clear plastic holder into which a collectible coin is often placed.
Flow lines
Lines that are not always visible that are caused by the metal flow from the center of the coinage blank caused at the moment the blank was struck by the working coinage dies.
Forgery
A counterfeit, an unauthorized coin or bank note meant to deceive.
Friction
Wear appearing only on the highest points of coinage detail on a high grade coin.
Frosting
When coin design elements are set apart from a mirrorlike surface by a sandblast-like or crystallized-metal appearance, this is referred to as frosting or frosted devices.
Galvano
The model for a coin design that serves as a lathe before the design is transferred to a coin-size hub.
Gold certificate
A U.S. paper bank note issued with a gold color seal and a statement that the note is redeemable for the same value in gold or in gold coins. These notes are legal tender; however they have not been redeemable in gold since 1933. The words “gold certificate” must appear somewhere on the note.
Grade
The condition assigned to a coin based on the amount of wear the coin has received from circulation.
Grade rarity
When a common date coin is available in an uncommonly nice condition that commands a premium when sold to coin collectors because of the grade rather than because of the date it is said to be a grade rarity.
Hairlines
Light lines that appear on the surface of a coin due to the coin having been cleaned.
Hammered coins
Coins struck by hand rather than struck by machine.
High relief
The design elements on a coin or a medal are sufficiently high that the item is unable to be stacked. These are artistic pieces usually desired by collectors.
Hub
The steel device made from a galvano with the image of the coin design in positive that will be transferred to the working coinage dies as a negative image.
Impaired proof
A proof coin that has been mishandled and is for that reason less than perfect.
Incomplete strike
A coin lacking part of the design due to a problem during production.
Incuse
When coin design elements are impressed rather than raised above the surface of the coinage blank.
Ingot
A bar, typically composed of precious metal.
Janvier reducing machine
The machine used to produce hubs from galvanos.
Jeton
A counter used on gaming boards or during antiquated accounting practices but also as a substitute for coins.
Jugate
Two busts overlapping on one side of a coin are said to be appearing jugate.
Karat
A way in which the purity of gold can be expressed, based on 24 karat gold being pure gold. As an example, 22 karat gold is actually the fraction 22/24 or .916 fine gold.
Key date
This is an important, rare date and mint mark coin without which a coin series is not complete.
Lamination
A thin piece of metal that separates partially or entirely from the surface of a coin, impacting the design elements in the process.
Legends
The inscriptions appearing on a coin. Blundered legends are legends in which a mistake can be seen.
Lettered edge
A legend appearing on the edge of a coin rather than about the rim.
Liner
A coin on the border between two grades. Liners between the grades about uncirculated and uncirculated are called “sliders.”
Lint marks
Miniscule light marks appearing on proofs due to hairlines created from lint originating from the fabric used when the dies were polished.
Love token
A coin on which one side has been planed off and replaced with engraved initials or a name.
Luster
The original glossy radiance of the surface of a coin originating from when it is first struck. Luster must be present for a coin to be considered to be uncirculated or mint state.
Marks
Detrimental blemishes appearing on coins due to contact with other coins or foreign objects.
Master die
The die made from a hub that will be used to make working coinage dies.
Master hub
The original hub made by the portrait lathe. The master hub will be used to make master dies.
Matte finish
A sandblast-like appearance on a proof or uncirculated coin.
Medal
A round metal object struck to honor or commemorate a person, place, or thing, or to display artwork. Medals are not legal tender and do not circulate as money or as a substitute for money.
Medieval coin
Any coin made between A.D. 476 (the date of the fall of the Roman Empire) and about 1500, that was produced by hand rather than machine.
Milling machine
Also known as an upsetting machine, this is the device through which coinage blanks are fed to upset the rims.
Milling marks
Marks left on the surface of a coin when that coin has made contact with the reeded edge of other coins.
Mint
A factory in which coins are made. Bank notes are not made in a mint unless the mint also has a security printing facility.
Mint error
Problems appearing on a coin originating from its manufacture, such as off-center strikes and coins lacking detail.
Mint luster
Also sometimes described as mint bloom, this is the original brilliance that appears on the surface of a coin when it is first struck. As a coin circulates and the surfaces wear, this luster dissipates and eventually is lost. Cleaning a coin will also remove any existing mint luster. There is no way to restore it.
Mint mark
Although mint marks do not appear on all coins, mint marks are initials or other identifying marks purposely placed on coins to identify the mint where coins were produced.
Mint set
A year set of uncirculated coins specially packaged and sold by a mint to collectors. These sets typically have a superior example of the same coins that are being released into circulation during that year.
Mintage
The number of coins produced of a specific date, mint mark, and denomination. Mintage records can suggest the availability of a coin, however they do not indicate the number surviving or the condition in which they survive, but simply the number manufactured.
Mishandled proof
A proof coin that is less than perfect due to handling, cleaning, or some other detriment following its production. Any coin grading less than proof 60 is a mishandled proof. Any proof coin graded less than proof 65 should be suspect.
Modern coin
Any machine-struck coins, typically dating from about 1500 or later depending on when the country of the coin's origin began to machine-strike coins.
Moneyer
The individual responsible for a mint. Moneyer's initials or symbols sometimes appear on their coins.
Mottled toning
Uneven toning that may present less than desirable eye appeal.
Motto
Legends on coins appearing as inscriptions, such as “In God We Trust.”
Nickel
A nickname for the 5-cent coin denomination based on the metal of the same name of which it is partially composed.
Noncirculating Legal Tender (NCLT)
A term applied to a specially struck coin, typically a commemorative, that although the coin has a legal tender value appearing on it, the coin is being issued for sale to collectors rather than to circulate as money.
Numismatist
A person who studies the economics, artistic quality, distribution, and other qualities of coins individually and as groups.
Obverse
The “heads” or face side of a coin.
Off-center strike
An error coin on which only part of the coin design appears due to the blank being out of position when the coin dies struck that blank.
Orange-peel surfaces
Surfaces on a gold coin that glow with an orange or sunset color due to remaining original toning.
Original toning
The glow from the surface of a coin when it was first struck. This original color effect disappears when a coin is circulated or cleaned.
Overdate
A date digit or several date digits impressed over another date digit on a coin.
Paper money
Another term for a bank note, however in recent history bank notes are no longer always made of paper.
Patina
The natural finish on the surfaces of a coin due to exposure to the environment.
Pattern
A coinlike product that is produced by a mint to test or demonstrate a potential new design, diameter, or metal composition for coinage.
Pedigree
The lineage of the ownership of a coin. Some coins can be traced to prestigious collections from the past.
Planchet
Blanks from which coins are produced.
Proof
A mirrorlike surface quality coin struck from higher polished dies and from specially prepared blanks or planchets, to be sold to collectors rather than circulated. Proof coins can typically be identified from their business strike quality counterparts by a squared rather than a round edge rim.
Prooflike
An uncirculated coin with mirrorlike surfaces similar to those of a proof coin.
Pure silver
Silver to the purity of .999 fine or .9999 fine (99.9 percent).
PVC (polyvinyl chloride)
A chemical used in plastic coin holders to make the holders flexible. PVC will react with the surface of coins, causing a green slime to appear on the surface nicknamed “green slime disease” or “PVC poisoning.”
Rarity
The desirability of a coin based on the difference between the number of coins available and the demand for these coins among collectors and investors.
Reeding
The notches or grooves that appear about the edges of many coins. The origin of reeding was to discourage clipping or shaving metal from precious metal coins.
Replica
A copy of a coin or bank note made for souvenir purposes rather than to deceive the public or coin collectors. Under the Hobby Protection Act, modern replica coins must be prominently stamped with the word “copy.”
Restrike
Coins struck at a later date than the initial issue, but using the same coinage dies. Not all restrikes are officially authorized.
Reverse
The “tails,” or back side of a coin.
Rim
The raised area at the edge of the obverse and reverse of a coin. Don't confuse rim with the edge of the coin itself.
Silver certificate
A U.S. paper bank note issued with a blue color seal and statement that the note is redeemable for the same value in silver. These notes are legal tender, however they have not been redeemable in silver since 1968.
Slider
A coin bordering on being graded either about uncirculated or uncirculated, often sold for the more optimistic grade by coin dealers.
Specie
The precious metal of a circulating coin, typically gold or silver content.
Sterling silver
Silver to the purity of .925 fine or .925 percent purity; often misunderstood to be pure silver.
Token
A round metal object issued privately rather than by a government issuing authority, able to be vended or used at a specific place as a substitute for government-issued money, sometimes within a certain time period.
Toning
The color changes on the surfaces of a coin due to the coin's contact with contaminants and chemical reactions with the atmosphere. Some collectors seek pleasing toning, while other insist on untoned coins.
Two-by-two holder
A cardboard holder with a see-through center typically of 2-by-2-inch size into which collectible coins are placed.
Type coins
Coins that are an example of their design type, typically collected in order to have an example of this design rather than due to the specific date and mint mark on the coin.
Variety
A minor change or alteration made in the design (also called “type”), date, or mint mark of a coin from what is otherwise the norm.
Vest pocket dealer
A part-time coin dealer who buys and sells at coin shows from an inventory he carries on his person rather than from bourse table space he has rented.
Vignette
The artistic designs appearing on bank notes. Weak strike
A poorly struck coin on which some of the detail is missing for this reason. Commonly confused with wear.
Wear
The grade or condition of a coin is due to wear.
