Numismatic Glossary

A mixture of two or more metals. Most coins are alloys rather than pure metals — for example, cupronickel is an alloy of copper and nickel used in many circulating coins worldwide.

The process of testing a metal to verify its purity and composition. Particularly important for gold and silver bullion, where an assay certificate confirms the metal content matches what's claimed.

The process of verifying that a coin is genuine rather than counterfeit. Professional grading services like PCGS and NGC authenticate coins as part of their grading process.

A small scratch or nick on a coin's surface caused by contact with other coins during storage or transport in mint bags. Common on large gold and silver coins. Also called contact marks.

A coin made from two different metals, typically a ring of one metal surrounding a centre of another. The most familiar example is the 2 Euro coin, which has a nickel-brass centre and a cupronickel outer ring.

A flat disc of metal that has been cut to the correct size and weight but not yet struck with a design. Also called a planchet. Blanks are fed into a coin press where dies stamp the design onto both sides simultaneously.

A striking standard above regular circulation coins but below Proof quality. BU coins are produced with care to preserve sharp detail and original lustre, but without the multiple strikes and polished dies used for Proofs.

Precious metal in the form of bars, coins, or rounds, valued primarily by weight and purity rather than design or rarity. Examples include the American Silver Eagle and the Austrian Vienna Philharmonic.

A visual effect on Proof coins where the raised design elements appear frosted white against a mirror-like field. A deep cameo (or ultra cameo) has strong, even frosting across the entire design.

A coin produced by pouring molten metal into a mould rather than striking it between dies. Ancient Chinese cash coins and early Roman bronzes were cast. Modern counterfeit coins are often made this way, which is one way to detect fakes.

A coin that has been used in everyday commerce and shows visible wear. The amount of wear determines the coin's grade — a lightly circulated coin retains more detail and value than a heavily worn one.

A coin made by bonding layers of different metals together. Most modern US coins are clad — a copper core with outer layers of cupronickel. Different from plated coins, where a thin coating is applied over a base metal.

A coin issued to honour a person, place, or event. Commemoratives are typically produced in limited quantities and sold at a premium above face value. Many countries issue commemorative coins annually.

The overall state of preservation of a coin, encompassing wear, surface quality, and eye appeal. Condition is the primary factor in determining a coin's market value beyond its base metal content.

A fake coin made to deceive collectors or pass as legal tender. Modern counterfeits range from crude cast copies to sophisticated die-struck fakes. Authentication services exist specifically to detect these.

The face value of a coin or note as stated by the issuing authority. A 2 Euro coin has a denomination of 2, expressed in Euros. The denomination may bear no relation to the coin's market or metal value.

A hardened steel cylinder engraved with a coin design in reverse. Two dies are used — one for the obverse and one for the reverse. When a blank is placed between them and struck with extreme force, the design is transferred to the coin.

A die that received a misaligned second impression during its manufacturing, producing coins with doubled lettering, dates, or design elements. Doubled die coins are considered errors and can be highly valuable.

The outer border of a coin, visible when viewed from the side. Edges can be plain (smooth), reeded (with vertical grooves), lettered (with inscribed text), or decorated. The edge of a 1 Pound coin, for example, carries an inscription.

A coin produced with a manufacturing mistake — wrong planchet, misaligned die, double strike, off-centre strike, clipped planchet, or other anomaly. Genuine mint errors are collected as a specialty and can command substantial premiums.

The area of a coin below the main design, typically separated by a horizontal line. The exergue often contains the date, denomination, or mint mark.

The overall visual attractiveness of a coin. Two coins with identical technical grades can have different eye appeal based on toning, lustre quality, strike quality, and the location and severity of any marks.

The flat background area of a coin's design — the smooth surface surrounding the portrait, text, and other raised elements. On Proof coins, the field is typically mirror-like.

The proportion of pure precious metal in a coin or bar, expressed as parts per thousand. A .999 fine gold bar is 99.9% pure gold. A .9167 fine sovereign is 91.67% gold (22 karat). Also expressed as purity.

A standardised assessment of a coin's condition. Grades range from Poor (PO-1) through Good, Fine, Very Fine, Extremely Fine, About Uncirculated, to Mint State (MS-60 through MS-70). See the Grading Guide for full details.

A company that professionally authenticates and grades coins, then encapsulates them in a tamper-evident holder with a grade label. The major services are PCGS, NGC, and ANACS for coins, and PMG for banknotes.

Fine, light scratches on a coin's surface, often caused by improper cleaning or wiping. Hairlines reduce a coin's grade and are a common reason graded coins receive lower scores than their wear level might suggest.

A coin where the design elements are raised significantly above the field, creating a sculptural, three-dimensional appearance. High relief coins are more expensive to produce and the highest points wear more quickly in circulation.

A catalogue reference number from the Krause-Mishler Standard Catalog of World Coins. Each distinct coin type worldwide is assigned a unique KM number, making it the standard way to identify and reference any world coin.

The main inscription on a coin, typically running along the rim. May include the country name, denomination, date, or a motto.

The natural surface shine of an uncirculated coin, caused by the flow of metal during the striking process. Original mint lustre is a key factor in grading — once lost through wear or cleaning, it cannot be restored.

A coin produced on a mechanical press, as opposed to a hammered coin struck by hand. Virtually all coins minted since the 17th century are milled coins, though the term is sometimes used to refer specifically to the reeded edge produced by a collar die.

The facility where coins are manufactured. Major mints include the United States Mint, the Royal Mint (UK), the Paris Mint, and the Austrian Mint. Many countries operate multiple mint facilities.

A small letter or symbol on a coin indicating which mint facility produced it. US examples include D for Denver, S for San Francisco, and W for West Point. Some mints, like Philadelphia, historically used no mint mark at all before 1980.

A set of uncirculated coins packaged by the mint, typically containing one of each denomination produced that year. Different from a proof set, which contains specially struck proof coins.

A coin that has never circulated and shows no wear. Mint State coins are graded on the Sheldon scale from MS-60 (uncirculated with many marks and blemishes) to MS-70 (perfect, no imperfections visible at 5x magnification).

The total number of coins struck of a particular design, date, and mint mark combination. Low mintage generally increases a coin's collectability and value, though demand and condition also matter.

A coin struck with mismatched dies — an obverse die from one coin type paired with a reverse die from another. Mules are rare mint errors and highly sought after by error collectors.

The study and collection of coins, banknotes, tokens, medals, and related objects. The term comes from the Greek word "nomisma" meaning coin.

A person who studies or collects coins and related items.

The front face of a coin, traditionally bearing the portrait of a head of state, national emblem, or other primary design. Informally called "heads."

An error where the blank was not properly centred between the dies when struck, resulting in part of the design being missing. The degree of off-centre strike is typically expressed as a percentage.

A coin struck on top of a previously struck coin. Sometimes done deliberately (repurposing existing coins) and sometimes as an error.

The natural surface colouration that develops on a coin over time through chemical reaction with the environment. On copper and bronze coins, patina typically appears as brown or green toning. A natural patina is generally desirable and should not be removed.

A trial or experimental coin struck by a mint to test a new design, denomination, or metal before regular production. Patterns are typically produced in very small quantities and are highly collectible.

A coin struck on a planchet that is thicker than standard, typically twice the normal thickness and weight. Piedforts are produced as collector pieces and are more expensive than standard issues. Pronounced "pee-a-for."

A coin with a thin coating of one metal applied over a core of a different, usually cheaper metal. Different from clad coins, where the layers are thicker and bonded mechanically. Modern circulating Euro coins use various plating techniques.

The highest striking standard for coins. Proof coins are struck multiple times on specially prepared polished planchets using polished dies, producing mirror-like fields and sharp, frosted design details. Proofs are made for collectors, not circulation.

A set of proof coins packaged by the mint, typically containing one of each denomination produced that year in proof quality. Often comes in a presentation case with a certificate of authenticity.

An edge with fine parallel grooves running vertically around the coin's perimeter. Originally introduced to prevent people from shaving metal off the edge of gold and silver coins. Also called milled edge.

A banknote printed to replace one that was damaged during the manufacturing process. Identified by a star symbol (in US currency) or a specific serial number prefix (in other countries). Collected as a specialty, especially in low serial number ranges.

A coin struck from genuine dies at a later date than the original issue. Some mints produce restrikes of popular historical coins, such as the Austrian Maria Theresa Thaler which has been restruck continuously since 1780.

The back face of a coin, typically bearing a design, coat of arms, or denomination. Informally called "tails."

The raised outer border of a coin that protects the design from wear. The rim also allows coins to be stacked neatly and processed by machines.

A group of related coins issued over time following a common theme. Examples include the US State Quarters series, the German Bundesländer 2 Euro series, and the Austrian Mythical Creatures collector coin series.

The standard numeric grading system for coins, ranging from 1 (identifiable but heavily worn) to 70 (absolutely perfect). Developed by Dr. William Sheldon in 1949 and adopted as the industry standard. See the Grading Guide for the complete scale.

The sealed, tamper-evident plastic holder used by professional grading services to encapsulate authenticated and graded coins. The holder displays the grade, certification number, and any special designations. Coins in slabs are referred to as "slabbed."

The current market price of a precious metal per troy ounce. Spot price is the baseline for bullion pricing — a gold coin or bar is typically priced as spot plus a premium that covers manufacturing, distribution, and dealer margin.

The act of stamping a design onto a blank between dies, or the quality of that impression. A well-struck coin shows full, sharp design details. A weakly struck coin may have soft or incomplete details, particularly on the highest points of the design.

Natural discolouration that develops on a coin's surface through oxidation over time. Toning on silver coins can appear as shades of blue, purple, gold, or rainbow colours and is often considered attractive and desirable. Artificial toning done to increase appeal is frowned upon.

The standard unit of weight for precious metals. One troy ounce equals 31.1035 grams — slightly heavier than a standard (avoirdupois) ounce of 28.35 grams. When bullion is quoted per ounce, it always means troy ounces.

The straight or shaped cutoff at the bottom of a portrait bust on a coin. The engraver's initials are often placed on or near the truncation.

A basic design of a coin that remains constant while other elements (date, mint mark) may change from year to year. Type collecting involves acquiring one example of each major design rather than every date and mint mark variant.

A coin that has never been used in commerce and retains its original mint lustre. An uncirculated coin may still have bag marks or other minor imperfections from handling at the mint — these affect the Mint State grade but do not constitute circulation wear.

A minor variation within a coin type, such as a different date size ("large date" vs "small date"), a doubled die, a repunched mint mark, or a difference in the number of design elements. Variety collecting is a deep specialty within numismatics.