Editing Metalworking (section)

==Prehistory==
The oldest archaeological evidence of [[copper]] [[mining]] and working was the discovery of a copper [[pendant]] in northern [[Iraq]] from 8,700 BCE.<ref>Hesse, Rayner, W. (2007). ''Jewelrymaking through History: an Encyclopedia.'' Greenwood Publishing Group. p. 56. {{ISBN|0-313-33507-9}}.</ref> The earliest substantiated and dated evidence of metalworking in the [[Americas]] was the processing of copper in [[Wisconsin]], near [[Lake Michigan]]. Copper was hammered until it became brittle, then heated so it could be worked further. In America, this technology is dated to about 4000–5000 BCE.<ref>{{cite book|author1=Emory Dean Keoke|author2=Kay Marie Porterfield|title=Encyclopedia of American Indian Contributions to the World: 15,000 Years of Inventions and Innovations|url=https://books.google.com/books?id=QIFTVWJH3doC&pg=PA14|access-date=8 July 2012|year=2002|publisher=Infobase Publishing|isbn=978-1-4381-0990-9|pages=14–}}</ref> The oldest [[gold]] artifacts in the world come from the Bulgarian [[Varna Necropolis]] and date from 4450 BCE.

Not all metal required fire to obtain it or work it. [[Isaac Asimov]] speculated that gold was the "first metal".<ref>Asimov, Isaac: "The Solar System and Back", pp. 151 ff. Doubleday and Company, Inc. 1969.</ref> His reasoning being, that, by its [[chemistry]], it is found in nature as nuggets of pure gold. In other words, gold, as rare as it is, is sometimes found in nature as a [[native metal]]. Some metals can also be found in [[meteor]]s. Almost all other metals are found in [[ore]]s, a mineral-bearing [[Rock (geology)|rock]], that require heat or some other process to liberate the metal. Another feature of gold is that it is workable as it is found, meaning that no technology beyond a stone [[hammer]] and [[anvil]] is needed to work the metal. This is a result of gold's properties of [[malleability]] and [[ductility]]. The earliest [[tool]]s were stone, [[bone]], [[wood]], and [[sinew]], all of which sufficed to work gold.

At some unknown time, the process of liberating metals from rock by heat became known, and rocks rich in copper, [[tin]], and [[lead]] came into demand. These ores were mined wherever they were recognized. Remnants of such ancient mines have been found all over [[Southwestern Asia]].<ref>Percy Knauth et al. "The Emergence of Man, The Metalsmiths", pp. 10–11 ff. Time-Life Books, 1974.</ref> Metalworking was being carried out by the [[South Asia]]n inhabitants of [[Mehrgarh]] between 7000 and 3300 BCE.<ref name=Possehl>Possehl, Gregory L. (1996). ''Mehrgarh'' in ''Oxford Companion to Archaeology'', Brian Fagan (Ed.). Oxford University Press. {{ISBN|0-19-507618-4}}</ref> The end of the beginning of metalworking occurs sometime around 6000 BCE when copper [[smelting]] became common in Southwestern Asia.

Ancient civilisations knew of seven metals. Here they are arranged in order of their [[oxidation potential]] (in [[volt]]s):

*[[Iron]] +0.44 V,
*[[Tin]] +0.14 V
*[[Lead]] +0.13 V
*[[Copper]] −0.34 V
*[[Mercury (element)|Mercury]] −0.79 V
*[[Silver]] −0.80 V
*[[Gold]] −1.50 V.

The oxidation potential is important because it is one indicator of how tightly bound to the ore the metal is likely to be. As can be seen, iron is significantly higher than the other six metals while gold is dramatically lower than the six above it. Gold's low oxidation is one of the main reasons that gold is found in nuggets. These nuggets are relatively pure gold and are workable as they are found.

Copper ore, being relatively abundant, and tin ore became the next important substances in the story of metalworking. Using heat to smelt copper from ore, a great deal of copper was produced. It was used for both [[jewelry]] and simple tools. However, copper by itself was too soft for tools requiring edges and stiffness. At some point tin was added into the molten copper and [[bronze]] was developed thereby. Bronze is an [[alloy]] of copper and tin. Bronze was an important advance because it had the edge-durability and stiffness that pure copper lacked. Until the advent of iron, bronze was the most advanced metal for tools and [[weapon]]s in common use (see [[Bronze Age]] for more detail).

Outside Southwestern Asia, these same advances and materials were being discovered and used around the world. People in [[China]] and [[Great Britain]] began using bronze with little time being devoted to copper. [[Japan]]ese began the use of bronze and [[iron]] almost simultaneously. In the Americas it was different. Although the peoples of the Americas knew of metals, it was not until the [[European colonisation of the Americas|European colonisation]] that metalworking for tools and weapons became common. Jewelry and [[art]] were the principal uses of metals in the Americas prior to European influence.

About 2700 BCE, production of bronze was common in locales where the necessary materials could be assembled for smelting, heating, and working the metal. Iron was beginning to be smelted and began its emergence as an important metal for tools and weapons. The period that followed became known as the [[Iron Age]].{{Cn|date=September 2024}}