Coin, Mexico, 5 Pesos
1985 - Mexico City - AU(50-53) - Brass - KM:502
National arms, eagle left.
Date and value
3.09 gr
Brass
Brass has had a variety of names over the year… It was known as orichalcum (aurichalcum) by the Ancient Greeks and Romans, Florentine or Venetian bronze, yellow copper, similor, and even tombac. Its name may vary depending on the proportions of the recipe and its origin, but the composition of this alloy remains the same: a successful and beautiful marriage of zinc and copper.
The alloy is variable in spirits and color: the more zinc dominates, the whiter its hue, the more copper dominates, the more it glimmers with golden highlights.
In its monetary form, there is evidence dating from the 1st century BC, in the area of Asia Minor, most likely in the Kingdom of Pontus. Its usage then spread throughout Asia and Europe. Augustus notably substituted it for bronze for certain dupondii and sesterces. Much later, in the 18th century, it was a popular choice for tokens. Pinchbeck (a low-end brass) was used on medals to imitate gold.
The properties of the alloy may vary depending on the proportions of metals employed, but it is well known for its great malleability and good resistance to corrosion.
When copper constitutes the majority, the patina may turn green.
An “AU(50-53)” 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(50-53)
This means – more prosaically – that the coin has circulated well from hand to hand and pocket to pocket but the impact on its wear remains limited: the coins displays sharp detailing and little sign of being circulated. The number (50-53) indicates that at least half of the original luster remains. Closer examination with the naked eye reveals minor scratches or nicks.
You might be wondering why there are different ranges of numbers behind the same abbreviation. Well, we’ll explain:
The numbers are subdivisions within a category, showing that the state of conversation is the same but coins may be at the higher or lower end of the scale. In the case of AU, the range (55-58) indicates that the luster is better preserved in than a similar coin described as (50-53).
