Alloy – Homogeneous mixture of two or more elements, where the resulting compound has metallic properties. Common coin alloys include cupronickel (copper and nickel) and bronze (copper and tin).
Assay – Test to ascertain the weight and purity of a coin.
Bag Mark – Surface mark, or nick, on a coin usually from contact with other coins in a mint bag. More often seen on large gold or silver coins. Also called “contact marks”.
Base metal – Non-precious metal or alloy containing no gold or silver. Common base metals used in coinage include nickel and copper.
Bi-metallic – A coin with one type of metal in the center with an outer ring of a different metal. An example is the Canadian “toonie” two-dollar coin.
Blank – Prepared disk of metal on which the coin design will be stamped. Also called a ‘planchet’ or ‘flan’. In practice, ‘Blank’ is also referred to the un-struck or flat side of a uniface coin or medal.
Brass – Copper based alloy with zinc.
Brockage – Originally referring to metal wasted in coin production, now means coins struck when the previous coin remains stuck to a die, creating an incuse impression in the next struck coin.
Bronze – Copper based alloy with tin.
Bullion – Precious metals (platinum, gold and silver) in the form of bars, ingots or plate, or where quantity is considered as a valuation. Also refers to coins whose market value is determined by metallic content rather than scarcity.
Bullion Value – Current market value of the raw precious metal content of a coin.
Business Strike – A coin intended for everyday use in commerce.
Cameo – Strong distinction in the surface appearance of foreground devices relative to the field. Proof coins often exhibit this feature.
Carat – Unit measurement of the weight of precious stones. Usually marked ‘c’ or ‘car’. 1 carat = 200 milligrams. Not to be confused with ‘Karat’ used with gold.
Cast Coins – Coins produced by pouring metal into a mold. Used for the first Ancient Roman bronze “As” coins and Chinese “cash” coins, but rarely used today. Modern counterfeit coins are often cast.
Certified Coin – Coin that has been graded and authenticated by one of numerous independent grading services.
Circulated – Term used to indicate a coin that has wear.
Clad Coinage – Issues of coins that contain a center core and outer layer of differing metals or alloys bonded together. The current U.S. Quarter, dime, and half dollar are made of cupronickel clad copper.
Coin alignment – A method of striking in which the obverse and reverse dies are aligned 180 degrees from each other. All American coins are struck this way.
Collar – Outer ring of the die chamber that holds the blank in place while the obverse and reverse are being stamped.
Contact Marks – Minor abrasions on uncirculated coinage from contact with other coins. Also called “bag marks”.
Countermark or Counterstamp – Partial or complete over-stamping of a coin or token in order to change its value or issuing authority, or to display an advertisement, political slogan or symbol, etc. Stamping may consist of a number (value), symbol (authority), letters (advertisement or slogan), or any combination of the above.
Crown – Large coin often struck in precious metal. Modern crowns are usually not highly-circulated due to being too large and/or too heavy. The United States’ last crown-sized coin for circulation was the Eisenhower Dollar, last struck in 1978.
Cud – A defect from a chipped die.
Debase – To lower the silver/gold value of the coin by altering its purity, but with the same face value as the pure coin. This often happens during periods of high inflation.
Denticles – Small tooth like projecting points on the inside edge of coins.
Designer – Artist or creator of a coin’s design.
Device – Pattern or emblem used in the design of a coin.
Die – Metal piece engraved with the design used for stamping the coin.
Die Clash – Caused when a coin planchet fails to be placed between two dies during the minting process, causing the dies to smash together. The design of one or both may impress into the opposite die, causing a “shadow” of the design to appear on subsequent coins minted with the damaged dies. The impact of the two dies may also result in die cracks or defects.
Die Crack – Fine raised line on a coin that was caused by a crack in the die.
Die Defect – Imperfection of various sorts caused by a damaged die. May refer to a crack or clash or a chip out of the die, etc. A defect from a chipped die is called a cud.
Die State – A variation in appearance to a coin struck by a single die, resulting from wear or alteration of the die. For example, the presence or absence of die cracks may signal a specific die state.
Die Variety – Minor variation in a die, including repunched mintmarks, doubling, or deliberate minor changes to the die design.
Dime– United States $0.10 coin. Derived from the old English “Tithe”, meaning “1 of 10” (The Dime is one tenth of a dollar.)
Dipped, Dipping – Chemical cleaning of a coin with a diluted acid.
Double Eagle (U.S.A) – United States gold $20 coin. Struck from 1850 to 1933.
Double strike – A coin where a die is struck, bounced, then struck again, offset from first strike.
Doubled Die – Die that received two misaligned impressions from a hub; more commonly, a coin struck by such a die.
Eagle (U.S.A)– United States $10.00 gold coin minted from 1795 – 1933 and a series of US Bullion coins minted from 1986 through the present.
Edge – Rim of a coin often containing a series of reeds, lettering or other decoration.
Effigy – The image or likeness of a person, usually on the obverse of a coin or medal.
Electrotype – Reproduction made by electro deposition frequently used in museum displays.
Encapsulated Coin– A coin that has been authenticated graded and enclosed in plastic by an independent service.
Engraver – Person who cuts the image of a design onto a die.
Error – Usually a mis-made coin not intended for circulation, but can also refer to an engraving or die-cutting error not discovered until the coins are released to circulation. The mis-made coin errors are usually unique, but the engraving errors appear on all of the coins produced until the error is corrected. This may result in two or more varieties of the coin in the same year.
Face Value – Value that is written on a coin. For example, an American 1 cent coin has a face value of 1 cent. A collectable coin or bullion coin is usually worth many times its face value.
Field – Background area of a coin not used for a design or inscription.
Filler – Coin that is very worn and/or damaged, but may still be included in a collection if it is a Key Coin.
Fineness – Purity of precious metal content expressed in terms of one thousand parts. 90% is expressed as .900 fine. The purest gold bullion coin is .99999 fine.
Flan – Blank metal piece before striking, also called a planchet or blank.
Flip Strike – An error caused by the coin flipping over after being struck, and then struck a second time. Each face of the coin will have a “ghost” of the opposite face.
Gem – Coin of exceptionally high condition, such as Gem Uncirculated or Gem Proof.
Grade – The condition of a coin or amount of wear that a coin has received. Common grade terms used in North America, from worst to best, are Poor (Po), Fair (Fr), About Good (AG), Good (G), Very Good (VG), Fine (F), Very Fine (VF), Extra/Extremely Fine (EF or XF), Almost Uncirculated (AU), Uncirculated (UNC), and Brilliant Uncirculated (BU). Grading criteria may also include color, luster, strength of strike, and “eye appeal”.
Hammered– A coin that has been struck by hand, using dies and a hammer.
High Relief – A coin with the raised design high above the field. Coins struck in high relief often have problems with details not coming up sharp enough and dies having a shorter than usual lifespan. If the design is higher than the rim, the coin may not be stackable, and the highest points of the design will wear away very quickly.
Hub – Positive-image punch that impresses the coin’s design onto a die.
Incuse – Part of the coin’s design that has been impressed below the surface. Not as popular as the “relief” method due to difficulty striking clearly and shorter lifespan of dies.
Ingot – Mass of pure metal from a mold. It may be stamped with its weight and purity.
Inscription – Lettering and wording on a coin.
Intrinsic Value – Current market value of a coin based on its metallic content. For a coin struck on precious metals, this is the same as its bullion value.
Karat – Unit measurement of the purity of gold. Usually marked ‘K’, or ‘k’. 24K = pure gold, 18K = .750 fine. Not to be confused with ‘Carat’ used with precious stones.
Key Coin – A rarer or higher valued coin within a series.
Laureate – Head crowned with a laurel wreath. The American Barber coins from 1892 to 1915 are examples.
Legal Tender – Coins or currency which must be accepted in payment of debt.
Legend – Principal inscription on a coin.
Lettered Edge – The outside edge of a coin containing an inscription.
Low Relief – A coin with the raised design not very high above the field.
Luster – Appearance of a coin’s ability to reflect light; brilliance. Percentage of the original mint luster is one of the factors in determining grades of “Mint State” coins (e.g. MS-60, MS-65).
Master die – Original die from which working hubs are made.
Milled edge – Raised rim around the outer surface of a coin.
Mint Error – Defective coin produced by a mint.
Mint Luster – Shiny “frost” on the surface of an uncirculated or mint state coin.
Mint Mark – Small letter (or other symbol) indicating at which mint the coin was struck. Examples are “CC” for Carson City, Nevada, “S” for San Francisco, “O” for New Orleans, “P” for Philadelphia, etc. on US coins.
Mint Roll – Uncirculated coins wrapped in rolls by issuing authority of a certain quantity.
Mint Set – Set of uncirculated coins packaged and sold by the mint.
Mint State(MS)– Another word for “Uncirculated”. Conditions range from MS-60 to MS-70.
Mis-strike – Off center striking of a coin.
Monster Box – Large plastic shipping boxes for silver bullion coins, holding 500 coins. US Silver Eagles are shipped in green monster boxes while Canadian Maple Leafs are shipped in red monster boxes.
Motto – Inspirational phrase or wording. Examples include “In God we Trust” on US coins or “Liberte, Egalite, Fraternite” on French coins.
Mule – Coin struck from two dies never intended to be used together.
Obverse – Front or heads side of coin.
Overdate – Shown date made by superimposing numbers on a previously dated die.
Over Graded – Coin in worse condition than stated.
Pattern – Coin minted from official dies that is not a regular issue, and intended to evaluate new alloys or designs.
Patina – Surface film caused by oxidation, usually green or brown, mostly found on older silver, copper or bronze coins.
Pedigree – Record of previous owners of a rare coin.
Planchet – Blank prepared piece of metal on which the coin is struck.
Proof – Coins specially struck for collectors using polished dies and planchets. The resulting coins usually have a mirror field and raised areas are frosted in appearance.
Proof Set – Set of proof coins packaged and sold by the U.S. Mint.
Quarter (U.S.A./Canada) – United States or Canada $0.25 coin. Short for Quarter Dollar.
Quarter Eagle (U.S.A) – United States gold $2.50 coin.
Raw – Coin that has not been encapsulated by any coin grading service.
Reeded Edge – Edge of a coin with grooved lines around the perimeter. Also known as a milled edge.
Relief – Part of the coin’s design that is raised above the field, opposite of “incuse”.
Re-strike – Coin struck from genuine dies at a date later than the original issue. Some of the 1804 US Silver Dollars for example were restrikes.
Reverse – Back or tails side of the coin. Opposite of ‘Obverse’.
Rim – Raised portion of the design along the edge that protects the coin from wear. It also makes the coins stackable and easy to roll by machine.
Round – Round one ounce bullion piece, generally issued privately.
Series – Set of year’s coin was minted with a specific design and denomination.
Silver Dollar – A one-dollar coin minted in the U.S. (until 1935), and Canada (until 1967). Dollar coins made after those dates are sometimes called “silver dollars” although they are actually made of nickel or other metal. Dollar coins struck in Canada since 1987 are more commonly referred to as Loonies because of the loon design on the reverse.
Slab – Plastic case containing a coin that has been graded and encapsulated.
Spot Price – Quoted market value of one troy ounce of a precious metal in bullion form.
Stainless Steel – A combination of iron, carbon and another element, usually chromium, to prevent rusting. Coins struck on stainless steel are very durable and maintain their shiny appearance, but the hardness of the metal requires that the coins have a low relief in order to prolong die life.
Token – Privately issued piece that has redeemable value for goods or services, but is not an official government coin. An example would be subway tokens.
Trade Dollar – Silver dollar issued specifically for trade with a foreign country.
Type – Coin’s basic distinguishing design.
Type Set – One of each coin of a particular design, series or period.
Uncirculated – Coin that has never been used, thus retaining all or most of its original luster.
Uniface – A coin struck with the design on one side only.
Unique – Item of which only one is known to exist.
Variety – Coin’s design that sets it apart from the normal issue.
Year Set – Set of coins for any specific year containing one of each denomination of that year.
Zinc – A grey inexpensive metal, usually alloyed with copper to make brass coins, but is also used in pure form for emergency coinage when the usual coinage metal is not available due to war or other serious crisis.