Copper Crystal - Native Copper
Copper Crystals first appeared in the Fourth Edition of the Mini Museum. We're happy to share these larger varieties of this naturally forming metal.
Above: Front of specimen card.
"... I will not accept here any copper from you that is not of fine quality." ~ Nanni, Babylonian Merchant to Copper Dealer Ea-Nasir, c. 1750 BCE
The intricate lattice of native copper crystals reveals a story of deep geological processes lasting hundreds of millions of years. Stronger than gold, but still soft enough to be shaped easily into tools, weapons, and decorative objects, this form of copper also played an important role in the development of human cultures across the globe as they stepped out of the Stone Age and into the Age of Metals.
Above: Copper Crystal specimens hanging out on a Permian sedimentary slab formed around the same time (geologically speaking).
This specimen is a branch of native copper from deposits located near the city of Zhezqazghan, Kazakhstan. The large copper deposits in this region are sediment-hosted with mineralization occurring roughly 300,000,000 years ago, and involving brines from late Devonian and early Permian marine sediments. The earliest copper mining in this region dates back to the Bronze Age, crossing numerous cultures, with extensive trade routes into the ancient world.
Above: Copper Crystal specimen in hand, illustrating the natural patina on these 300,000,000-year-old specimens.
As pictured, the specimen is enclosed in a handsome, glass-topped riker box case measuring 4 1/2" x 3 1/2". A small information card is also included that also serves as the certificate of authenticity.
Please Note: Specimens vary widely in size and shape. Very roughly, they are 1.5" in diameter (3-4cm). The images here are representative only. In addition, each specimen is wrapped in bubble wrap for the protection of the specimen and the case. This is pure copper and it is quite malleable. Use caution when handling as it is easy to bend and break these delicate forms. Also, keep in mind that they are 300,000,000 years old so there may be a small amount of patina on the surface.
More about Copper
Most metallic elements are found in combined states such as ores and alloys. Even iron, which is one of the most abundant metals in the Earth's crust, is typically alloyed with nickel. Pure or "native" metals are relatively rare, with the exception of less reactive elements such as gold, silver, platinum, and copper.
Native copper deposits are found in both igneous and sedimentary rock formations, but the processes involved in their formation are quite different. In the case of igneous rocks, native copper crystallizes in lava flows which have low silicon and low sulfur content. Known as mafic lava, the lack of silicon makes the flow more viscous and the lack of sulfur keeps the copper from forming ores as it cools. Sedimentary-hosted native copper forms through a long process of reduction. Copper is extracted from host rocks soaking in chalky or calcareous brines. These deposits occur in highly permeable sediments in shallow marine basins near the paleoequator where there would have been a high evaporation rate.
Copper tools and decorative objects date back as far as 10,000 years ago, but for thousands of years, use of copper was limited to the availability of uncombined or “native” metal. Widespread use of copper did not occur until humans learned to extract it from ores through smelting.
Above: King Shulgi of Ur, carrying a basket, c. 2095-2047 BCE
Smelting is a process that uses heat and reducing agents to cause a chemical reaction that frees the pure metal from other elements such as sulfur (sulfides) and oxygen (oxides). Tin and lead, which can be smelted in simple hearths, were the first metals extracted using this method. Copper smelting came later, possibly as a side effect of the heat generated in pottery kilns.
Later, tin and copper would be combined to create an alloy known as bronze, a durable material that would shape the ancient world for thousands of years.
Copper remains an indispensable metal in the modern world. It is highly conductive, which makes copper useful for all manner of electrical components. It is also ductile and malleable, two traits that allow copper to be stretched and formed without breaking. This makes copper ideal for wiring and plumbing.
And yet, despite its long history, we’re still not quite done with this incredible metal.
Recent studies have demonstrated that raw copper is a powerful antimicrobial material, highly effective at killing bacteria, viruses, and fungi on contact by disrupting cell membranes. Copper ions are also at the heart of studies in molecular motion, and the construction of tiny, synthetic molecular machines.
Today we might post a tweet or drop a comment on Facebook, but roughly 3,768 years ago when something went wrong you had to grab a stiff reed, make hundreds of little wedge-shaped marks in clay, and then wait for it to dry.
Above: "The Complaint Tablet" of Ea-nasir
This particular cuneiform tablet comes from the ancient, coastal city of Ur. It is a complaint letter from the Merchant Nanni to a Copper Dealer named Ea-nasir.
Translated from Akkadian it says:
When you came, you said to me as follows: "I will give Gimil-Sin (when he comes) fine quality copper ingots." You left then but you did not do what you promised me. You put ingots which were not good before my messenger (Sit-Sin) and said: "If you want to take them, take them; if you do not want to take them, go away!"
What do you take me for, that you treat somebody like me with such contempt? I have sent as messengers gentlemen like ourselves to collect the bag with my money (deposited with you) but you have treated me with contempt by sending them back to me empty-handed several times, and that through enemy territory. Is there anyone among the merchants who trade with Telmun who has treated me in this way? You alone treat my messenger with contempt! On account of that one (trifling) mina of silver which I owe(?) you, you feel free to speak in such a way, while I have given to the palace on your behalf 1,080 pounds of copper, and umi-abum has likewise given 1,080 pounds of copper, apart from what we both have had written on a sealed tablet to be kept in the temple of Samas.
How have you treated me for that copper? You have withheld my money bag from me in enemy territory; it is now up to you to restore (my money) to me in full.
Take cognizance that (from now on) I will not accept here any copper from you that is not of fine quality. I shall (from now on) select and take the ingots individually in my own yard, and I shall exercise against you my right of rejection because you have treated me with contempt.
Translations of 150 different letters like this letter are available in A. Leo Oppenheim's 1967 book, "Letters From Mesopotamia: Official, Business, and Private Letters on Clay Tablets from Two Millennia"
Above: Back of specimen card.