VOCABULARY TERMS: MINTMASTER'S MARK AND MORE

Mintmaster's Mark. The signature, usually the initial, of the chief official of a mint, infrequently found on coins and medals. Such personal signatures were in addition to that of the die engraver, or mintmark (often two such marks would appear on the same coin, rarely three, as this did lead to some confusion). A modern example is the precious metal products of the jewelry firm of Tiffany & Co., where, since 1880, all items were signed with the last initial of the president's name (M for Edward C. Moore, P for Henry B. Platt, and such). In a way, it meant the president guaranteed the quality of the piece that bore his initial much like that of a mintmaster's mark.

To read the complete entry on the Newman Numismatic Portal, see:
Mintmaster's Mark (https://nnp.wustl.edu/library/dictionarydetail/517199)

Mirror Image. Matching opposite polarity; a reflected image. Struck pieces are a mirror image of their dies; dies are a mirror image of their hub or patrix. Positive and negative plaster casts are mirror images of each other. A mirror image is called contraposition. The congruent interface surfaces of two-part medals are often mirror images of each other. Compare retrograde lettering.

To read the complete entry on the Newman Numismatic Portal, see:
Mirror Image (https://nnp.wustl.edu/library/dictionarydetail/516334)

Misaligned Die. A striking error from one or both dies not seated properly during setup, or working loose (chattering) during striking. There are two kinds of misaligned dies: (1) vertical – where the dies strike pieces one side of which is off center while the other side is perfect, and (2) horizontal – in which the dies are tipped causing them to strike wedge shaped pieces. The latter pieces lack parallelism. When dies are made it is required that the top and bottom are absolutely parallel. When they are placed in a press this parallelism is required as well. Dies tipped at any stage of their manufacture or use will result in misaligned error strikes. Collectors have abbreviated this term as MAD.

Reference:
NM19 {1991} Margolis, p 293-295.

To read the complete entry on the Newman Numismatic Portal, see:
Misaligned Die (https://nnp.wustl.edu/library/dictionarydetail/516337)

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