The earliest verified iron artefacts uncovered to date are composed of meteoritic iron. They comprise nine ancient iron beads found in two graves in Gerzeh in northern Egypt in 1911 and date to around 3,200 BC1. Whilst establishing the meteoritic origins of the iron in the beads in 2013, scientists also discovered they were made from thin hammered sheets of iron that had been rolled into tubes. Four of the beads in one grave were threaded onto a necklace with beads made from other precious materials, namely gold, carnelian, lapis lazuli, and agate. The other 3 beads in this particular grave were found at the waist of the body. The remaining 2 iron beads were located in another grave that also contained a wide variety of other beads made from calcite, carnelian, chalcedony, faience, garnet, gold, lapis lazuli, obsidian, serpentine and steatite.
Symbolic – Iron As A Precious Metal
The presence of other precious minerals with these iron beads appears to indicate that iron was ranked alongside them in terms of value, and that all these types of metals and materials were important symbols of wealth and status. It also seems that minerals in general were not originally sought out and used for utilitarian or functional purposes but rather "to serve as aesthetic visual displays of identity, whether of a social, cultural or ideological nature" (Roberts et al., 2009: 1019)2.
Just as significantly, the iron beads further indicate that metal workers knew about iron and how to work with it long before the dawn of the official Iron Age around 1,200 BC. In fact, there is growing evidence that iron was being used a lot earlier than originally thought3. Whilst much of it was the meteoric iron that had 'arrived' on earth in a native state that didn't need smelting, there are records of sporadic terrestrial iron smelting occurring from the mid Bronze Age period (~2,200 BC – 1,570 BC) onwards.
The Earliest Evidence Of Smelted Iron
Archaeological excavations at Kaman-Kalehöyük in Turkey unearthed some fragments of iron dating to around 2,200 – 2,000 BC. Subsequent archaeometallurgical analysis confirmed the presence of carbon, indicating the items were made from smelted terrestrial iron rather than meteoritic iron, which contains nickel. Therefore, it seems that in Central Anatolia at least metal workers knew how to smelt terrestrial iron as early as the late 3rd millennium BC and were producing a limited but steady supply of iron products, probably for a very select and elite market, throughout the early to late mid 2nd millennium BC.
This concept is supported by findings elsewhere around the pre-historic world. Tutankhamun for instance owned an iron sword made for him during the 14th century BC, a time when bronze still reigned supreme, especially for weapons, so he clearly had access to speciality iron products.
In India, ancient iron-working facilities in the Ganges Valley have been dated to 1,800 BC. There is also evidence that iron was being smelted and used to produce various artefacts across a wide area of the Eastern Vindhyas and Central Ganga Plain around the same time. Likewise, iron artefacts dating from the same period have turned up in Southeast and South Asia and the Middle East whilst in Africa some of the iron artefacts found there were made as early as 2,000 BC. A distinguishing feature of these items is the lack of nickel in the iron, indicating a terrestrial rather than meteoritic source.
Slightly more recently, the iron pillar of Delhi was built during the reign of Chandragupta II (375 – 415 AD) and has been studied for its noted corrosion-resistance qualities. India also has some famous iron cannons that are several centuries old.
Although smelting of other metals (copper, tin etc) was in full swing by the end of the 3rd millennium BC, iron's high melting point was problematic for most furnaces of the day. Metals with low to moderate melting points, like copper and tin, could be smelted in many of the furnaces readily available at the time (pottery kilns etc) but these facilities simply couldn't reach the required temperatures needed to smelt iron. This effectively restricted iron processing to all but a few purpose-built facilities, hence the 'sporadic' nature of recorded terrestrial iron smelting at this time.
Furthermore, terrestrial iron may be abundant but the ores in which it is found contain a number of other compounds that have to be removed during the smelting process. Early iron metal workers would have quickly discovered this, and realised they had to develop somewhat complex procedures to remove these impurities.
It probably also didn't take them long to find out that pure iron is soft, brittle and not a particularly useful commodity in that state. That meant experimenting with additives to find out what worked most effectively as a hardener, and calculating the precise amounts needed to produce an optimal balance of strength and hardness. The metal also needed hot work to finish it off.
These are all processes that would have taken time to develop and perfect. It paid off though because the result was a product called steel, a tough, durable alloy of iron and carbon that ultimately shaped the development of human civilisation.
The Spread Of Iron Making Technology
It's possible that the shift away from bronze, and the eventual collapse of the Bronze Age, was accelerated by disruptions to Mediterranean trade routes and tin shortages around 1,300 BC. This put pressure on metal workers to find alternatives to bronze, particularly for weapons manufacture. Many bronze objects were in fact recycled for this purpose but ultimately, when demand for products exceeds availability of the materials they're made from, it's only a matter of time before manufacturers are forced to look for alternatives. In this case, they found that alternative in iron, which may explain the rapid explosion of interest in iron and iron products that signalled the beginning of the Iron Age around 1,200 BC. It may also explain King Tut's iron sword.
Once it came into widespread use, steel's popularity as a building medium has never waned. We found all sorts of uses for it, most notably in building and construction. It's safe to say that without iron, and the steel produced from it, our world would look completely different. Today, iron accounts for around 90% of all refined metals globally.
This magnetic field is what protects life on earth from the harsh solar environment. Earth's sister planet Mars has a much weaker magnetic field and its surface has been buffeted by solar winds that have stripped it bare. And speaking of planets – one thing they all have in common is iron in their core.
- 5,000 years old Egyptian iron beads made from hammered meteoritic iron
- Development of Metallurgy in Eurasia (p 1019)
- The Significance of Early Bronze Age Iron Objects from Kaman-Kalehöyük, Turkey
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