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mail bid sale An auction sale where bidding is limited to bids by mail. (Today, that also may include by phone, fax, or email.)
major variety A coin that is easily recognized as having a major difference from other coins of the same design, type, date, and mint. See also minor variety.
market grading A numerical grade that matches the grade at which a particular coin generally is traded in the marketplace. The grading standard used by PCGS.
marks Imperfections acquired after striking. These range from tiny to large hits and may be caused by other coins or foreign objects.
master die The main die produced from the master hub. Many working hubs are prepared from this single die. See also master die, working hub, working die.
master hub The original hub created by the portrait lathe. Master dies are created from this hub.
Matte Proof An experimental Proof striking, produced by the U.S. Mint mainly from 1907 to 1916, which has sandblasted or acid-pickled surfaces. These textured surfaces represented a radical departure from brilliant Proofs, having even less reflectivity than business strikes.
MD Short for medium date.
medal press A high-pressure coining press acquired by the U.S. Mint, circa 1854-1858, to strike medals, patterns, restrikes, and some regular-issue Proofs.
medium date Term referring to the size of the digits of the date on a coin. (Use of this term implies that a large or small date exists for that coin or series.)
medium letters Term referring to the size of the lettering of the date on a coin. (Use of this term implies that large or small letters exist for that coin or series.)
melt Slang term for the intrinsic value of a particular numismatic item. (Whats the melt value of that ten Lib?)
Mercury dime Common name for the Winged Liberty Head dime issued from 1916 until 1945. The A.A. Weinman motif was quickly compared to the Roman god Mercury and the name stuck with the public.
metal stress lines Radial lines, sometimes visible, that result when the metal flows outward from the center of the planchet during the minting process. See also flow lines.
milling mark A mark that results when the reeded edge of one coin hits the surface of another coin. Such contact may produce just one mark or a group of staccato-like marks. See also reeding mark(s).
minor variety A coin that has a minor difference from other coins of the same design, type, date, and mint. This minor difference is barely discernible to the unaided eye. The difference between a major variety and a minor variety is a matter of degree. See also major variety.
mint A coining facility.
mint bloom Original luster that is still visible on a coin. See also luster, lustrous.
mint error See also error.
mint mark Variation of mintmark
mint set A set of Uncirculated coins from a particular year comprising coins from each Mint. (Usually, this term refers to government issued Mint Sets, although for many years, it has been loosely used for any set of Uncirculated coins from a particular year. Also, the government Mint Sets issued from 1947 until 1958 were double sets.)
mint set toning This term refers to the colors and patterns coins have acquired from years of storage in the cardboard holders in which Mint Sets were issued from 1947-1958. Since 1959, Mint Sets have been issued in plastic sleeves, thus they do not tone as spectacularly.
Mint State The term corresponding to the numerical grades MS-60 through MS-70, used to denote a business strike coin that never has been in circulation. A Mint State coin can range from one that is covered with marks (MS-60) to a flawless example (MS-70).
mintage The number of coins of a particular date struck at a given mint during a particular year. (This may not equal the official mintage for that calendar year, especially for pre-1840 coinage. The Mint reported coins struck in the calendar year, regardless of the date(s) on the issue. For instance, the 1804-dated dollar was included in Proof Sets struck in 1834 because the official mintage figures for 1804 included silver dollars although it is now known that these were dated 1803 or possibly even earlier.)
mintmark The tiny letter(s) stamped into the dies to denote the mint at which a particular coin was struck.
mishandled Proof A Proof coin that has been circulated, cleaned, or otherwise reduced to a level of preservation below PR-60. See also impaired Proof.
Miss Liberty Term applied to the various incarnations of the emblematic Liberty represented on United States coinage.
mis-struck Term applied to the error coins that have striking irregularities.
ML Short for medium letters.
monster Slang for an incredible coin, usually one that grades MS/PR-67 or higher. A secondary use is as an adjective, such as monster luster or monster color.
moose Slang for an incredible coin, usually one that grades MS/PR-67 or higher.
Morgan Short for Morgan dollar.
Morgan dollar The common term used for the Liberty Head silver dollar struck from 1878 until 1904 and again in 1921. George Morgan was the assistant engraver but his design was selected over William Barbers for the dollar. Morgan was passed over for the Chief Engravers job when William Barber died in 1879. Charles Barber, Williams son, received the job and Morgan remained an assistant until Charles died in 1918. Morgan was then elevated to position of Chief Engraver, which he held until his death in January, 1925.
mottled toning Uneven toning, usually characterized by splotchy areas of drab colors.
Motto An inscription on a coin especially IN GOD WE TRUST, which first appeared on the 1864 two-cent piece andnow is required on all U.S. coinage.
MS-60 This is for "Mint State" (the grade) and "60" (the numerical designation of that grade). This is the lowest of the eleven Mint State grades that range from MS60 through MS70. An MS60 coin will usually exhibit the maximum number of marks and/or hairlines. The luster may range from poor to full, but is usually on the "poor" side. Eye appeal is usually minimal. See also Mint State.
MS-61 This is for "Mint State" (the grade) and "61" (the numerical designation of that grade). This grade meets the minimum requirements of Mint State plus includes some virtues not found on MS60 coins. For instance, there may be slightly fewer marks than on an MS60 coin, or better luster, or less negative eye appeal. See also Mint State.
MS-62 This is for "Mint State" (the grade) and "62" (the numerical designation of that grade). This grade is nearly in the "choice" or MS63 category, but there is usually one thing that keeps it from a higher grader. Expect to find excessive marks or an extremely poor strike or dark and unattractive toning. Some MS62 coins will have clean surfaces and reasonably good eye appeal but exhibit many hairlines on the fields and devices. See also Mint State.
MS-63 This is for "Mint State" (the grade) and "63" (the numerical designation of that grade). The equivalent of "choice" or "Choice BU" from the days before numerical grading was prevalent. This grade is usually found with clean fields and distracting marks or hairlines on the devices OR clean devices with distracting marks or hairlines in the fields. The strike and luster can range from mediocre to excellent. See also Mint State, choice.
MS-64 This is for "Mint State" (the grade) and "64" (the numerical designation of that grade). This grade is also called "Borderline Gem" at times, as well as "Very Choice BU." There will be no more than a couple of significant marks or, possibly, a number of light abrasions. The overall visual impact of the coin will be positive. The strike will range from average to full and the luster breaks will be minimal. See also Mint State.
MS-65 This is for "Mint State" (the grade) and "65" (the numerical designation of that grade). This grade is also called "Gem" or "Gem Mint State" or "Gem BU." There may be scattered marks, hairlines or other defects, but they will be minor. Any spots on copper coins will also be minor. The coin must be well struck with positive (average or better) eye appeal. This is a NICE coin! See also Mint State, Gem, Gem BU.
MS-66 This is for "Mint State" (the grade) and "66" (the numerical designation of that grade). This is not only a Gem-quality coin, but the eye appeal ranges from "above average" to "superb." The luster is usually far above average, and any toning can not impede the luster in any significant way. This is an extra-nice coin. See also Mint State.
MS-67 This is for "Mint State" (the grade) and "67" (the numerical designation of that grade). A superb-quality coin! Any abrasions are extremely light and do not detract from the coins beauty in any way. The strike is extremely sharp (or full) and the luster is outstanding. This is a spectacular coin! See also Mint State.
MS-68 This is for "Mint State" (the grade) and "68" (the numerical designation of that grade). A nearly perfect coin, with only minuscule imperfections visible to the naked eye. The strike will be exceptionally sharp and the luster will glow. This is an incredible coin. See also Mint State.
MS-69 This is for "Mint State" (the grade) and "69" (the numerical designation of that grade). Virtually perfect in all departments, including wondrous surfaces, a 99% full strike (or better), full unbroken booming luster and show-stopping eye appeal. You may have to study this coin with a 5X glass to find the reason why it didnt grade MS70. See also Mint State.
MS-70 This is for "Mint State" (the grade) and "70" (the numerical designation of that grade). A perfect coin! Even with 5X magnification there are no marks, hairlines or luster breaks in evidence. The luster is vibrant, the strike is razor-sharp, and the eye appeal is the ultimate. Note: Minor die polish and light die breaks are not considered to be defects on circulation strike coins. See also Mint State.
Mule Error This is a rare Mint error where the obverse die is of one coin and the reverse die is of another coin. The most famous of the Mule errors is a Sacagawea dollar/Washington quarter Mule, where a Washington quarter obverse is paired with a Sacagawea reverse.
multiple-struck See also double-struck.
mutilated A term used to describe a coin that has been damaged to the point where it no longer can be graded.
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