Letter M

Golden Glossary of Coin Terminology

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Master Die

The die which is used to produce several hubs, which in turn are used to make many working dies. The master die is never used to strike coins. See Hub.

Matte Proof

A certain type of proof coin minted in the United States, mostly from 1908 to 1916. Matte proofs have a dull, granular finish without any mirrorlike qualities.

Milling Mark

Also reeding 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 the mint bag. Milling marks are generally more detrimental to the grade than normal bag marks, because of their severity of depth and greater visual impact.

Minor Coin

Small-denomination coins which have little bullion value.


Facility where coins are manufactured.


Act of manufacturing coins in a mint.

Mint Mark

Indicates at which mint the coin was manufactured. Usually a small letter.

Mint Set

A coin of each denomination produced by a given mint in a particular year.

Mint State

Also Uncirculated. Describes coins showing no trace of wear. Mint State grades range from MS60 to MS70.

Mishandled Proof

A proof coin which somehow escaped into circulation or was otherwise significantly abused. Also referred to as an impaired proof.


Anything that is accepted as a medium of exchange.