I recently read an article entitled "Patina is not the indicator of great age" published in The Central States Archaeological Journal that claims that copper artifacts from the Old Copper Culture (circa 4000-2000 BCE) sometimes lack any patina. However, articles published in The Central States Archaeological Journal do not appear to be peer-reviewed. I am wondering what the oldest copper artifact is that any of you have encountered that lacks any patina.
It is true, the patina forms after a few years and therefore it doesn’t indicate antiquity.
I don’t know of any pre-protohistoric copper or bronze objects without patina.
In some countries, moreover, it was the rule to remove the old patina (it is not done in Italy)
I don’t know the journal and the article and therefore I cannot evaluate the reliability of the text.
Copper artifacts can develop a patina relatively quickly under typical environmental conditions due to exposure to air, moisture, and other environmental factors. The formation of patina, which is primarily copper carbonate (often green or bluish in color), can begin within just a few years, especially in outdoor or humid environments.
However, the exact time it takes for patina to develop and the extent of its formation depends on several factors:
Environmental Conditions: In dry, stable environments with little exposure to air and moisture, the patina formation can be significantly slowed. In controlled environments, such as in certain archaeological contexts, copper artifacts have been found with minimal patina even after hundreds or thousands of years.
Surface Treatment: If the copper was treated or coated with a protective layer (such as lacquer, oil, or other organic substances), it could resist patina formation for an extended period.
Composition of the Copper Alloy: Pure copper might develop patina faster than certain copper alloys, which may include elements like tin or zinc that can slow down the patina formation process.
In an ideal scenario, with perfect preservation conditions (e.g., sealed in a dry, airtight container or buried in an anoxic environment), a copper artifact could potentially remain without significant patina for several centuries, if not millennia. However, this is rare, and most copper artifacts, even those just a few decades old, will show some degree of patina unless they have been specially preserved.
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