Copper - The foundation metal of ancient civilizations

[robinjojo]

Going back approximately 10,000 to 7,000 years ago copper, in its native or ore forms, played a central role in the development of early civilizations around the globe.  In the Mediterranean Cyprus, whose name is derived from the Greek Kupros was by far the most important source of copper, with Spain another important source.  Other lesser sources were from Egypt (Sinai), Greece and other parts of Europe and the Middle East.

With copper tools, implements and other objects, civilization moved into the Bronze Age (circa 3300-1200 BC), when copper, combined with tin, produced a much harder and durable composite metal.  Bronze continued as a dominant metal into the Iron Age and beyond, including  its use in many of the coins that we collect today.

Here's a link to the Mets site on Cyprus, with beautiful photos of bronze objects from Cyprus:

https://www.metmuseum.org/toah/hd/cyco/hd_cyco.htm#:~:text=The discovery of rich copper,10%2C had to be imported.

Copper, like silver, is a reactive medal, unlike gold.  Copper, due to its atomic structure, easily lends itself to combine with oxygen, through air or water.  Additionally other elements combine with copper to create the oxide minerals that are commonly mined for copper, both today and in ancient times.

However, there are deposits of copper in native, pure form.  These deposits are definitely the exception.

Native copper specimens

Native copper with silver, Keweenaw Peninsula, Michigan acid cleaned, 353.3 grams.

This native copper specimen was cleaned with muriatic acid.  There is also a concentration of silver towards the left. Sometimes copper occurs in combination with silver and even sometimes gold in very minor quantities. 

 

 

Native copper  Keweenaw Peninsula Michigan, not cleaned, 96.3 grams.

This is a native copper specimen in pretty much "as found" condition.  Note the oxide minerals forming on the surface: malachite (pale green) and cuprite (reddish brown).

 

Native copper, Keweenaw Peninsula, Michigan, found in Lake Superior by a scuba diver, 1,282.8 grams.

This unusual "float" specimen was found in Lake Superior, off the Keweenaw shore.  The surfaces are rounded by the sand and wave action of the lake, which also produced an even brown patina of cuprite.

 

Native copper, Zlaté Hory, Czech Republic, "skull" form, 717.2 grams.

Europe has its own ancient and historical sources of copper, including Cornwall in the UK and Zlaté Hory in the mineral rich region of Bohemia in the Czech Republic.  This specimen is sometimes referred to as a copper "skull" due to its peculiar form.

 

Copper ore specimens

The vast majority of copper deposits, today and in ancient times, are in the form of ore bodies, formations that bear copper oxides and other minerals in commercially viable quantities to warrant extraction.  Copper loves to react with its environment, so ore bodes with malachite, azurite, bornite, cuprite and other copper minerals are the rule; native copper deposits are the rare exceptions.

Here are a few ores of copper.  A link with a more comprehensive list follows.

Malachite and Azurite, 1,125.7 grams.

Malachite (CuCO3•Cu(OH)2) and Azurite (2CuCO3·Cu(OH)2) have a copper yield of approximately 57.7% and 55.1% respectively when refined.

 

Cuprite, Ray Mine, Arizona.

Cuprite (Cu2O) has an approximate copper yield of 88.8% making it one of the highest yielding copper ores and therefore a principal one.

 

Bornite "peacock" ore.

Bornite (2Cu2S·CuS·FeS) owes its name as peacock ore due to the tarnish surface that develops quite rapidly when fresh pieces are exposed to air.   This ore has an approximate copper yield of 63.3%.

 

Here's the link:

https://en.wikipedia.org/wiki/List_of_copper_ores

I hope this short posting gives you an ideal of where the copper in that bronze coin you're holding came from, and the mineral that help change the course of human history.

 

 

Edited August 22, 2022 by robinjojo

[expat]

Great write up and beautiful imagery. Thanks for that