Numismatic Glossary

A comprehensive guide to coin collecting terminology. From "About Uncirculated" to "Wear," understand the language of numismatics.

A

About Uncirculated (AU): A coin grading level (AU-50 to AU-58) describing a coin with only the slightest trace of wear on the highest points of the design. Nearly all original mint luster remains. See our grading guide for details on each AU level.

B

Bag Mark: A minor abrasion or nick on a coin caused by contact with other coins during storage or transportation in mint bags. Bag marks are common on uncirculated coins and are a key factor in distinguishing between Mint State grade levels (MS-60 through MS-70).
Brilliant Uncirculated (BU): A coin that retains its original mint luster without any trace of wear. Often used informally to describe coins in the MS-60 to MS-63 range, though the term is not part of the official Sheldon grading scale.
Business Strike: A coin produced for general circulation through normal minting processes. Business strikes are distinguished from proof coins, which are made using special techniques for collectors. The vast majority of coins in existence are business strikes.

C

CAC (Certified Acceptance Corporation): An independent coin verification service founded by John Albanese in 2007. CAC reviews coins already graded by PCGS or NGC and affixes a green sticker (for coins at the high end of their grade) or gold sticker (for coins that exceed their grade). CAC-stickered coins typically command premiums of 10-30% or more.
Cameo (CAM): A proof coin that displays a noticeable contrast between frosted raised design elements and mirror-like fields. The cameo designation adds value to proof coins. A stronger version, Deep Cameo (DCAM), commands even higher premiums.
Certified Coin: A coin that has been authenticated and graded by a professional grading service such as PCGS or NGC. Certified coins are encapsulated in tamper-evident plastic holders (slabs) with the grade clearly displayed. Certification provides market confidence in the coin's authenticity and condition.
Clad: A coin made from layers of different metals bonded together. Most modern US coins (quarters, dimes, half dollars) are clad, with a copper core sandwiched between layers of copper-nickel. Clad coinage replaced silver coins for circulation beginning in 1965.
Cleaned: A coin that has been chemically or mechanically altered to improve its appearance. Cleaning removes original toning and luster, and is considered damage by grading services. Cleaned coins receive "Details" grades from PCGS and NGC, which significantly reduces their market value.
Coin Roll Hunting (CRH): The practice of searching through rolls of coins obtained from banks to find valuable dates, errors, varieties, or silver coins. A popular and low-cost entry point for new collectors.
Condition Census: A ranking of the finest known examples of a particular coin. The top 5 (or sometimes top 10) known specimens are tracked by advanced collectors and registries. Condition census coins command the highest premiums.
Contact Mark: A mark on a coin resulting from contact with other coins or hard surfaces. Similar to bag marks, contact marks affect the grade of uncirculated coins. Their size, number, and location determine how much they impact the grade.
Cull: A coin in very poor condition — heavily worn, damaged, or cleaned — but still identifiable by type. Culls are typically valued close to their melt value for precious metal coins, or at minimal collector value for base metal coins.

D

DDO (Doubled Die Obverse): A variety where the obverse (front) die received a doubled impression during the die-making process, resulting in a visible doubling of design elements such as lettering, the date, or Liberty's features. Famous DDO coins include the 1955 and 1972 Lincoln cents, which command significant premiums.
DDR (Doubled Die Reverse): A variety where the reverse (back) die received a doubled impression during the die-making process, resulting in visible doubling of design elements such as the eagle, denomination, or motto. Less common than DDO varieties but equally collectible.
Deep Cameo (DCAM): A proof coin with exceptional contrast between heavily frosted raised design elements and deeply mirrored fields. The frost appears thick and "sculptural." Deep Cameo proofs command the highest premiums among proof coins of a given grade.
Denomination: The face value of a coin as designated by the issuing authority. US coin denominations include the cent, nickel, dime, quarter, half dollar, and dollar, as well as historical denominations like the half cent, two-cent piece, three-cent piece, twenty-cent piece, and various gold denominations.
Designer: The artist who created the original design for a coin. Famous US coin designers include Augustus Saint-Gaudens (Double Eagle, Indian Eagle), James Earle Fraser (Buffalo Nickel), Victor David Brenner (Lincoln Cent), and Adolph Weinman (Walking Liberty Half Dollar, Mercury Dime).
Details Grade: A designation given by PCGS and NGC to coins that have been cleaned, damaged, or otherwise impaired. The coin receives a grade (e.g., "AU Details") indicating what its grade would be based on wear alone, but the "Details" qualifier significantly reduces its value compared to a straight-graded coin of the same level.
Die Crack: A raised line on a coin caused by a crack in the die used to strike it. As dies wear from repeated use, stress fractures develop. Metal fills these cracks during striking, creating raised lines on the coin. Minor die cracks are common; dramatic ones (called "die breaks" or "cuds") can be quite valuable.
Die Variety: A variation in a coin's design caused by differences in the die used to strike it. Die varieties include repunched mint marks (RPM), repunched dates, doubled dies (DDO/DDR), and over-mint marks. Collectors actively seek notable die varieties, which often command premiums.

E

Edge: The third side of a coin, sometimes called the "third face." US coins have four main edge types: reeded (vertical grooves, found on dimes, quarters, and half dollars), plain (smooth, found on cents and nickels), lettered (inscribed text), and starred (found on some early coins).
Error Coin: A coin that deviates from the intended design due to a mistake in the minting process. Error types include off-center strikes, wrong planchet errors, clipped planchets, broadstrikes, and double strikes. Dramatic errors can be extremely valuable to collectors.
Eye Appeal: The overall visual attractiveness of a coin. Eye appeal is subjective but real: a coin with exceptional toning, strong luster, and a sharp strike may sell for more than a technically higher-graded coin with dull or unattractive surfaces. Grading services factor eye appeal into their assessments.

F

Face Value: The legal monetary value stamped on a coin. A quarter has a face value of $0.25 regardless of its collector value or metal content. Most collectible coins are worth far more than their face value. See also: melt value.
Fineness: The purity of a precious metal in a coin, expressed as a decimal or fraction. For example, a coin with .900 fineness is 90% pure silver (or gold). Modern American Silver Eagles have .999 fineness (99.9% pure silver).
Full Bands (FB): A strike designation for Mercury Dimes indicating that the horizontal bands on the fasces (reverse) are fully separated and distinct. Full Bands coins command significant premiums over coins without the designation.
Full Bell Lines (FBL): A strike designation for Franklin Half Dollars indicating that the horizontal lines at the bottom of the Liberty Bell (reverse) are fully visible and complete. FBL coins are significantly more valuable.
Full Steps (FS): A strike designation for Jefferson Nickels indicating that five or six steps on Monticello (reverse) are fully struck and clearly visible. Full Steps nickels, especially in high grades, can be worth many times more than their non-FS counterparts.

G

Grade: A numerical assessment of a coin's condition on the Sheldon scale (1-70). Grade is the most important factor in determining a coin's value. Professional grading by PCGS or NGC provides market-accepted grades. See our complete grading guide for grade descriptions.

H

Hairlines: Fine, thin scratches on a coin's surface, often caused by improper cleaning or wiping. Hairlines are most visible on proof coins and in the open fields of uncirculated coins. They significantly reduce a coin's grade and value. This is why collectors are warned never to clean their coins.

K

Key Date: A coin within a series that is significantly rarer and more valuable than most other dates in that series. Key dates typically have the lowest mintages, highest survival attrition, or both. Examples include the 1909-S VDB Lincoln Cent, 1916-D Mercury Dime, and 1893-S Morgan Dollar. Key dates anchor a coin series and are the most sought-after by collectors.

L

Luster: The brilliance or sheen of a coin resulting from the flow of metal during the striking process. Original mint luster appears as a "cartwheel" effect when the coin is rotated under a light. Luster is a key factor in grading uncirculated coins, and its quality (brilliant, satiny, frosty) varies by era and mint.

M

Melt Value: The value of the precious metal content in a coin if it were melted down. For silver coins (pre-1965 dimes, quarters, half dollars), this is based on the current spot price of silver. For gold coins, it is based on gold's spot price. A coin's collector value is typically above its melt value, but common-date silver coins in low grades often trade near melt.
Mint Mark: A small letter on a coin indicating which US Mint facility produced it. Common mint marks include P (Philadelphia), D (Denver), S (San Francisco), O (New Orleans), CC (Carson City), and W (West Point). Mint marks significantly affect value, as some mint facilities produced far fewer coins than others in a given year.
Mint State (MS): A coin that shows no trace of wear. Mint State grades range from MS-60 (uncirculated with many contact marks) to MS-70 (perfect). The term is synonymous with "uncirculated." See our grading guide for the full Mint State scale.
Mintage: The total number of coins of a particular date, mint mark, and denomination produced by a mint. Lower mintage generally (but not always) correlates with higher value. Mintage figures are tracked in our database for every coin and displayed on each coin's price guide page.

N

NGC: Numismatic Guaranty Company, one of the two leading professional coin grading services (alongside PCGS). Founded in 1987, NGC grades coins on the Sheldon scale and encapsulates them in tamper-evident holders. NGC is especially prominent in world coin and ancient coin grading.
Numismatics: The study and collection of coins, paper money, tokens, and medals. A person who studies or collects coins is a numismatist. The field encompasses history, art, economics, and metallurgy.

O

Obverse: The front or "heads" side of a coin. On US coins, this typically features a portrait (Lincoln, Jefferson, Roosevelt, Washington) or allegorical figure (Liberty). The obverse is considered the primary side of the coin.
Overdate: A coin where one date is punched over a different date. In early US coinage, dies were sometimes reused by punching a new date over the previous year's date. The underlying date may be partially visible. Overdates are collectible varieties, with some commanding significant premiums.
Over Mint Mark (OMM): A coin where one mint mark was punched over a different mint mark, such as a "D" over an "S." This occurred when dies were shipped between mint facilities and re-marked. OMM varieties are collected and can carry premiums, particularly for clear and dramatic examples.

P

Patina: The natural surface coloring that develops on a coin over time due to chemical reaction with the environment. Unlike artificial toning, natural patina is considered desirable by many collectors, particularly on copper and bronze coins where it can range from chocolate brown to deep olive.
PCGS: Professional Coin Grading Service, one of the two leading professional coin grading services (alongside NGC). Founded in 1986, PCGS grades coins on the Sheldon scale and encapsulates them in tamper-evident holders. PCGS coins often trade at a slight premium for US coins.
Planchet: The blank metal disc that is struck by dies to create a coin. Planchets are punched from metal strips and may be annealed (heat-treated) and upset (edge-raised) before striking. Planchet errors, such as wrong-metal planchets or clipped planchets, are collectible.
Population: The number of coins of a specific date, mint mark, and grade that have been certified by a grading service. PCGS and NGC maintain population reports that help collectors assess relative rarity within each grade level. Low-population coins in high grades command the strongest premiums.
Proof: A specially produced coin made using polished planchets and specially prepared dies, resulting in sharp detail and mirror-like surfaces. Proofs are struck for collectors, not for circulation. Modern proofs often display cameo or deep cameo contrast. Proof is a method of manufacture, not a condition; proof coins are graded on a separate PR/PF scale (PR-60 to PR-70).

R

Raw: A coin that has not been professionally graded and encapsulated by a grading service like PCGS or NGC. Raw coins are "unslabbed" and their grade is subject to the buyer's own assessment. Raw coins generally trade at a discount compared to certified coins of the same quality.
Repunched Mint Mark (RPM): A variety where the mint mark was punched into the die more than once, resulting in visible doubling or shifting of the mint mark. RPMs were common before 1990 when mint marks were individually punched into each die. Collectors catalog and collect RPM varieties, with dramatic examples commanding premiums.
Restrike: A coin struck from original dies at a date later than the year shown on the coin. Restrikes are official mint products but were made after the original production run, sometimes years or decades later. Some restrikes are valuable in their own right.
Reverse: The back or "tails" side of a coin. On US coins, the reverse typically features an eagle, building, or other national symbol. The reverse design can change over a series' lifespan while the obverse remains the same.

S

Semi-Key Date: A coin within a series that is scarcer and more valuable than common dates but not as rare as key dates. Semi-key dates have above-average collector demand and typically command moderate premiums. They are often the most affordable "better date" coins for collectors building sets.
Sheldon Scale: The 1-to-70 numerical grading system used to assess coin condition. Created by Dr. William Sheldon in 1949 and adopted as the industry standard. The scale ranges from P-1 (Poor, barely identifiable) to MS-70 (perfect). See our complete grading guide for all grade levels.
Slab: The tamper-evident plastic holder used by grading services to encapsulate certified coins. The slab displays the coin's grade, certification number, and other identifying information. "Slabbed" coins are the standard for buying and selling valuable coins in the modern market.
Spot Price: The current market price for one troy ounce of a precious metal (gold, silver, platinum, or palladium). Spot price is used to calculate the melt value of precious metal coins and fluctuates continuously during market hours.
Strike: The process of pressing a design into a blank planchet using dies, creating a coin. "Strike quality" refers to how well the design details were impressed during minting. A fully struck coin shows complete design detail, while a weakly struck coin may have soft or incomplete details, particularly in the centers or on high-relief elements.

T

Toning: Natural discoloration on a coin's surface caused by chemical reactions between the metal and its environment over time. Attractive toning (rainbow, blue, gold) can significantly increase a coin's value, while dark, blotchy, or uneven toning may decrease it. Artificial toning is detectable by grading services and reduces value.
Type Coin: A coin collected as a representative example of a particular design type, regardless of specific date or mint mark. Type collectors focus on acquiring one example of each major design (e.g., one Indian Head Cent, one Mercury Dime) rather than every date and mint mark. This approach is more affordable than building a complete set.

V

Variety: A coin that differs from the standard design due to a variation in the die, such as a doubled die, repunched mint mark, or repunched date. Varieties are cataloged and collected, with significant varieties commanding premiums. See also: DDO, DDR, RPM.

W

Wear: The loss of metal from a coin's surface due to friction from handling or use in commerce. Wear appears first on the highest points of a coin's design. The amount and location of wear is the primary factor in determining grades for circulated coins (AG-3 through AU-58).

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