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Doubled die (also known as hub doubling) is a term in numismatics used to refer to a duplication of design elements on a working die created due to a misalignment of the die or hub during the hubbing process. Strength of the doubling can vary from very slight and isolated to extreme and widespread.
A seemingly similar variety to the 1955 doubled die is the so-called 1955 "Poor Man's Doubled Die" cent, created by die deterioration doubling. It is caused when the design on a worn die becomes eroded and distorted, causing part of the design (such as the final digit of the date) to appear doubled.
A VAM occurs as a result of a die variety which creates the same variation on a number of coins. [1] The discovery and cataloging of VAM dollars is concerned with small differences in coins. Leroy Van Allen (VA) and A. George Mallis (M) documented the small variations and VAM comes from the initials of their last names.
In 1904, President Theodore Roosevelt tried to beautify American coins by enlisting the sculptor Augustus Saint-Gaudens to design a $20 gold coin, or double eagle. Today, that coin is considered ...
The die variation is clearly evident with the placement of the D in two different locations, one closest to the 1970 and the other closest to the rim of the coin. [1] There are some variations created by the mint site using different die sets. The best case of the mint using different die sets is the variation of the letters AM on the Lincoln cent.
However, it too wears the dies when they are used for too long. An infamous example is the 1955 "poorman’s double die." This coin is sold as a replacement for the 1955 doubled die cent, but it is no more than Die Deterioration Doubling, caused by wear on the dies. When a coin is struck, the planchet is not heated. Although the planchet would ...
In mathematics, a dual abelian variety can be defined from an abelian variety A, defined over a field k. A 1-dimensional abelian variety is an elliptic curve , and every elliptic curve is isomorphic to its dual, but this fails for higher-dimensional abelian varieties, so the concept of dual becomes more interesting in higher dimensions.
The dies for making modern proof coins are often treated with chemicals to make certain parts of the design take on a frosted appearance, with the polished fields taking on a mirror finish. Several other methods have been used in the past to achieve this effect, including sand blasting the dies, and matte proofs. Proof coins of the early 19th ...