Coin Collecting A to Z

Coin Collecting Terms - Letter M

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Machine doubling - Doubling of details resulting from loose dies during the striking process (much more common and much less valuable than die doubling).

Mail-bid sale - Similar to an auction, but all bids and transactions are completed through the mail or by telephone; no bidding is conducted "in person."

Major variety - A coin that is widely recognized as having a major difference from other coins of the same date, design, type, and mint.

Maple Leaf - A gold bullion coin of Canada. It is composed of .9999 fine gold. Produced in four sizes: 1-ounce with a $50 face value; half-ounce, $25; quarter-ounce, $10; and tenth-ounce, $5.

Maria Theresia taler - An Austrian silver trade coin dated 1780, but struck repeatedly since then with the one date.

Market grade - The grade at which most reputable dealers and auction houses would offer an uncertified coin.

Marks - Imperfections acquired after a coin is struck.

Master die - A metal punch used to produce "working hubs," which are then used to produce "working dies."

Master hub - The original hub created by the portrait lathe. Master dies are created from this hub.

Matte proof - A proof coin with a grainy surface appearance produced by dies treated to obtain a minutely etched surface.

Maverick - An unidentifiable specimen, generally referring to a token.

MD - Acronym for medium date.

Medal - A coin-like object struck to honor one or more persons or events depicted or mentioned in its design; an object awarded to persons in recognition of service or other accomplishment.

Medal press - A high-pressure coining press acquired by the U.S. Mint, in the 1850s. It was used to strike medals, and other issues.

Medalet - Depending on sources, a small medal no larger than 1 inch in diameter or a medal 35 millimeters in diameter or less.

Medallion - A large Roman presentation piece of the fifth century. Sometimes used for a large medal, usually three or more inches in diameter.

Medieval coin - A coin struck from about A.D. 500 to 1500.

Medium date - Term referring to the size of the digits of the date on a coin. The use of this term implies that a large or small date exists for the coin or series.

Medium letters - Term referring to the size of the lettering on a coin. The use of this term implies that large or small letters exist for that coin or series.

Melt - Refers to the value of a coin's metal content as determined by the current spot price of that metal.

Mercury - The unofficial nickname given to the Winged Liberty Head dime of 1916-45. The designer never intended the coin to depict Mercury, a male Greek god with wings on his ankles. The bust on the dime is an allegorical female Liberty Head figure with a winged cap.

Mercury dime - Common name for the Winged Liberty Head dime issued from 1916 through 1945. (Also “Merc”).

Metal flow - A combination of heat and compression from the dies, metal and presses that creates a melded appearance to a coin.

Metal stress lines - Radial lines, sometimes visible, caused by metal flowing outward from the center of the planchet during the minting process.

Micro - Very small or microscopic.

Milled - Struck on coin blanks cut from rolled strips. Often wrongly used to denote the reeded edge of a coin.

Milled edge - A raised rim around the outer surface of a coin. Not to be confused with the reeded or serrated narrow edge of the coin.

Milling mark - A series of two or more small nicks on a coin which result from contact with the reeded edge of another coin, usually in a mint bag. Milling marks are generally more detrimental to the grade than normal bagmarks, because of their severity of depth and greater visual impact.

Milling - Milling refers to the devices on the edge of a coin; a milled coin is one struck by machine. They are related due to the rise of the importance of the collar with machine-produced coinage.

Minimum Bid - Refers to the lowest monetary value that will be accepted at an auction as a bid on a coin.

Minor coin - A silver coin of less than crown weight, or any coin struck in base metal.

Minor variety - A coin that has a minor difference from other coins of the same design, type, date, and mint.

Mint - A facility where coins are crafted.

Mint bloom - Original lustre that is still visible on a coin.

Mint error - A mis-struck or defective coin produced by a mint.

Mint luster - The sheen or bloom on the surface of an Uncirculated numismatic object resulting from the centrifugal flow of metal caused by striking with dies. Mint luster or bloom is somewhat frosty in appearance as opposed to the mirror-like smoothness of the field of a Proof.

Mint mark - A letter or symbol used to denote the mint which produced the coin.

Mint set - A specially packaged group of uncirculated coins from one or more mints of the same nation containing at least one coin for most or all of the denominations issued during a particular year.

Mint set toning - Term referring to toning acquired by coins after years of storage in their original cardboard holders.

Mint state - A level of preservation signifying the same basic condition as when originally delivered from the mint.

Mintage - The total number of pieces of a specific date, type, denomination and mintmark originally struck for circulation.

Mint-Sealed / Mint Sewn - Describes a bag of coins sealed at an official Mint.

Mirror - Highly reflective surface or field of a coin; usually mirror field with frosted relief.

Mishandled Proof - A proof coin that somehow escaped into circulation or was otherwise significantly abused.

Misplaced date - One or more digits of a date punched away from the intended location, such as in the denticles or in the central design.

Mis-struck - Term applied to “error coins” with striking irregularities.

ML - Acronym for medium letters.

Model, Plaster - A clay or plaster three-dimensional design for a coin or medal.

Modern coin - A coin struck after about A.D. 1500.

Money - A medium of exchange.

Moneyer - An authorized mint master or coiner.

Morgan - Synonym for Morgan silver dollars.

Morgan dollar - Term for the Liberty Head silver dollar struck from 1878 through 1904 and once again in 1921.

Mottled toning - Splotchy, uneven toning.

Motto - An inspirational word or phrase used on a coin.

MS - Acronym for Mint State.

Mule - A coin struck from two dies not intended to be used together.

Multiple strike - A coin struck more than once as a result of not being properly ejected from the coining press.

Mutilated - A coin that has been damaged to the point where it no longer can be graded.

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