Terms You Might Find Helpful

Adjustment marks

Marks made on a coinage blank to ensure consistency when used to become a coin.

Altering (Doctoring)

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.

Artificial toning

Tarnish appearing on a coin caused by purposeful improper storage to create the surface colors now appearing on that coin.


A destructive test through which the purity of metal can be determined. 

Bag marks (Contact Marks)

Detrimental marks on the surface of a coin caused by banging against other coins when stored in bags. 


A pie-shaped piece cut from a Spanish 8-real coin to make change.


The round metal disk, or planchet, specially cut in preparation for the coin images to be added to make a coin.


Slang term for the Certified Coin Dealer Newsletter. 


French word for the area of a coin show where dealers buy and sell coins.

Branch Mint

A distant coin-making plant from the Philadelphia Mint, run by the federal government.


An error coin on which one side is struck correctly, however the other side is the incuse mirror image of this other side.


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, or any collector value.


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 or Album friction

The rub a coin receives from movement while in storage in a coin collection.

Carbon spots

Detrimental oxidation specks (usually black) appearing on the surfaces of a coin.

Cartwheel luster

The surface brilliance of an Uncirculated coin originating from when the coin was first produced. So named because it gives the appearance of the spokes in a large wheel on a cart or coach spinning as the vehicle travels along.


A coin or bank note made in the likeness of the authentic piece with the intent to deceive.

Double Eagle

Name for a U.S. gold coin valued at 20 dollars (often called a $20 gold piece).


Name adopted by the Coinage Act of 1792 for a gold coin valued at 10 units of the dollar ($10). In modern times, the name used to refer to gold, silver, and platinum coins of the U.S. Mint’s bullion coinage program begun in 1986.


The outermost periphery of a coin between the two sides (obverse and reverse). The edge can be plain, reeded, ornamented, or lettered.


A copy of a coin, medal, or token made by electroplating.


The person at the mint who designs the coinage dies.

Error Coins

Coins displaying mistakes (off-center, doubled letters or numbers, etc.) made during production.

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 nominal legal-tender value assigned to a given coin by the governing authority. In other words, how much you could buy with the medium.


A Roman symbol of authority consisting of a bound bundle of rods and an axe (seen on the reverse of Mercury dimes).


The flat area of a coin's obverse or reverse, surrounding the devices and legends.


The purity of a precious metal of a coins, 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.


A 2-by-2-inch clear plastic holder into which collectors store coins.

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.


Light circulation-wear appearing only on the highest points of coinage detail on a high grade coin.


A reproduction of a proposed design from an artist's original model produced in plaster or other substance and then electroplated with metal.


The subjective practice of examining coins or pieces of paper money and providing a numerical or adjectival description of their condition ratings.

Gresham's law

Sir Thomas Gresham, a 16th century English financier, said that when two monetary units with the same face value but different intrinsic values are in circulation at the same time, the one with the lesser intrinsic value will remain in circulation while the other is hoarded.


Slang term for the Coin Dealer Newsletter. 

Half eagle

Name adopted by the Coinage Act of 1792 for a gold coin valued at five units of the dollar ($5).


A piece of die steel showing the coinage devices in relief. The hub is used to produce a die that, in contrast, has the relief details incuse. The die is then used to produce the final coin, which looks much the same as the hub. Hubs may be reused to make new dies.


A coin's principal lettering, generally shown around its periphery.

Lettered edge

Incuse or raised lettering on a coin's edge.

Matte proof

A Proof coin on which the surface is granular or dull. On U.S. coins this type of surface was used on Proofs of the early 20th century.

Magician's coin

A term sometimes used to describe a coin with two heads or two tails. Such a coin is considered impossible in normal production due to physical differences in obverse and reverse die mountings, though as of 2001 two have been certified as genuine by professional coin authenticators. The vast majority are products made outside the Mint as novelty pieces, used by the “flipper” to always win the coin toss.


The total number of coins struck during a given time frame, usually one year.


A letter (or letters) or other marking on a coin's surface to identifying its mint of origin.


The combination of two coinage dies, or two plates for paper money not intended for use together.


The science, study or collecting of coins, tokens, medals, paper money, and related items.


The front or "heads" side of a coin.


Variety produced when one or more digits of the date are re-engraved over an old date on a die at a mint, generally to extend the life of dies or correct an error. Portions of the old date can still be seen under the new one.


Variety created at a mint when a different mintmark is punched over an already existing mintmark, generally done to make a coinage die already punched for one mint usable at another mint. Portions of the old mintmark can still be seen under the new one.


A coin struck over another coin.


A trial strike of a proposed coin design, issued by the Philadelphia Mint to receive approval or rejection for use as a new coinage design. Patterns can be in a variety of metals, thicknesses, and sizes.

Phrygian cap

A close-fitting, egg-shell-shaped hat placed on the head of a freed slave when Rome was in its ascendancy. Hung from a pole, it was a popular symbol of freedom during the French Revolution and in 18th century United States. An example of this is depicted on Liberty Seated coins from the U.S. Mint.


A disc of metal or other material on which the image of the dies are impressed, resulting in a finished coin. Also sometimes called a blank.


A coin struck at least two times on polished planchets, using specially polished dies. This resulted in typically bold definitions on all raised devices, and reflectively mirrored surfaces. Modern Proofs are prepared with a deeply mirrored finish. Some of the early 20th century Proofs were prepared with a matte surface.


A Prooflike coin exhibits some of the characteristics of a Proof despite having been struck in the normal production as a Business Strike. Morgan dollars are often found with Prooflike surfaces.

Quarter eagle

Name adopted by the Coinage Act of 1792 for a gold coin valued at 2.5 units of the dollar ($2.50).


The groove-and-tooth effect applied to the coin's edge during striking.


The portion of a design raised above the surface of a coin.


A coin produced from original dies at a later date, often with the purpose of sale to collectors (examples of the 1804 silver dollar are the most famous).


The backside or "tails" side of a coin.


The raised area bordering the edge and surrounding the field of coin.


Complete groupings of coins of the same denomination and design and representing all issuing mints. Can also be applied to subset groupings of coins of the same denomination and design that comprise all of the dates issued from a certain mint for that denomination.


A privately issued piece, generally in metal, with a represented value in trade or offer of service. Tokens are also produced for advertising purposes. Sometimes called “good-fors,” as in good for 12 ½ cents.


Coloring acquired from a metallurgic effect because of the atmospheric environment in which a coin is stored. It often results in attractive red, blue, yellow, green hues, which give the appearance of a work of art. Basically, it’s just another term for tarnish.

Type coin

A coin from a given series representing the basic design. For example, the Carson City Mint issued ten different types of coins, seven in silver and three in gold.


Any coin noticeably different in die diagnostics from another of the same design, date and mint. Overdates and over-mintmarks are examples of varieties.

Wire edge

Created when coinage metal flows between the coinage die and collar, producing a thin projection of coin metal at a coin’s outer periphery.