Coin, Mexico, 100 Pesos
1985 - Mexico City - AU(55-58) - Aluminum-Bronze - KM:493
National arms, eagle left.
Head 1/4 right with diagonal value at right
11.9 gr
Aluminum bronze
Bronze (not to be confused with brass, although usage of the two terms varied in times of yore) is an extremely ancient alloy of copper and tin with origins going back to the period around 2,000 BC. Also known...wait for it...as the Bronze Age (who would have guessed?)
In contrast, the addition of the third wheel, aluminum, is a far more recent development, as the technique for extracting aluminum from bauxite was only perfected in the 19th century.
The proportion of aluminum used for this extremely corrosion-resistant alloy is generally 15%. Small quantities of other materials such as magnesium are also sometimes added.
Its is frequently used for coinage.
An “AU(55-58)” quality
As in numismatics, it is important that the state of conservation of an item be carefully evaluated before it is offered to a discerning collector with a keen eye.
This initially obscure acronym comprising two words describing the state of conservation is explained clearly here:
About Uncirculated(55-58)
This means – more prosaically – that the coin has been in circulation but sufficiently little that its original beauty is preserved almost in its entirety. The wear is barely visible and any other defect can only be identified with a magnifying glass or a particularly keen eye. The number (55-58) indicates that between three quarters and almost all of the original luster remains.
