Scientists have long speculated that the ancient Egyptians used metal from meteorites to make iron objects. Now an analysis of a dagger found in Tutankhamun's tomb has given us strong evidence that this was the case – and that the Egyptians knew the iron had come from the sky. But why did they use such an unusual source for the metal when there's plenty of iron here on Earth?
Until recently, we didn't think that the ancient Egyptians were particularly good at producing iron objects until late in their history, around 500 BC. There's no archaeological evidence for significant iron working anywhere in the Nile Valley. Even the large amounts of iron-rich smelting waste products found in the Delta region could actually have been produced by attempts to make copper. When Tutankhamun died – 800 years earlier – iron was a rarer material than gold.
The most common natural source of metal iron on Earth is iron ores – rocks that contain iron chemically bonded to other elements. These need to be processed by heating them with other materials (smelting) to extract a low-quality form of iron, which is then beaten with hammers to remove impurities. This requires considerable know-how, effort and tools that we have no evidence for in ancient Egypt.
There were abundant supplies of iron ore in both Egypt and the Sinai peninsula and textual sources indicate that Egyptians were aware of the metal from early in their history. But the ore was mostly used to create pigments for art and make up. One explanation for this may be that the readily accessible iron ores were of poor quality so couldn't be worked into more useful metal.
But iron doesn't just come from iron ore. We have evidence that numerous prehistoric societies worldwide which did not have access to ores or knowledge of smelting made use of metallic iron found in occasional meteorites. This precious gift from nature still required shaping into a useful form, often resulting in very basic iron objects, such as small thin metal pieces that could be used as blades or bent into shapes.
If ancient Egyptians knew that iron could be found in meteorites that came from the sky – the place of the gods – it may have been symbolically important to them. As a result, they could have seen all iron as a divine material that wasn't appropriate to work into a practical, everyday form and that should be reserved only for high-status people.
Meteorites may have even played a more direct role in state religion. For example, the "Benben" stone worshipped in the sun temple of the god Ra at Heliopolis is thought to have possibly been a meteorite. The word "benben" is derived from the verb "weben", meaning "to shine".
The ancient language also offers clues as to how how iron was perceived by Egyptians – and that they knew meteorites were a source of the metal. The earliest hieroglyphic word for iron was greatly debated by translators, who frequently confused the words for copper and iron. The word "bi-A" was eventually translated as "iron", but could easily have referred a range of hard, dense, iron-like materials.
The word was used in many texts including the funerary Pyramid Texts, early religious writings dating from approximately 2375 BC but likely to have been composed far earlier, carved on the internal walls of some pyramids. These textual references to iron connect it with aspects of the sky and with the bones of the dead king who will live for ever as an undying star in the sky.
From the beginning of the 19th Dynasty (approximately 1295 BC) a new hieroglyphic word for iron appeared: "bi-A-n-pt", which literally translates as "iron from the sky". Why this new word appears in this exact form at this time is unknown but it was later applied to all metallic iron. An obvious explanation for the sudden emergence of the word would be a major impact event or large shower of meteorites.
This would have been witnessed by much of the ancient Egyptian population, leaving little uncertainty as to where exactly the mysterious iron came from. One possible candidate event is the Gebel Kamil meteorite impact in southern Egypt. Although its exact date remains unknown, based upon nearby archaeology we know it occurred within the past 5000 years.
Iron is also connected to ritual artefacts such as those used in the Opening of the Mouth ceremony, a ritual performed at the entrance of a tomb designed to transform the mummy into a latent being with the potential for life. Later texts, including temple inventories, that reference the equipment used in this ceremony refer to the iron blades used as "the two stars". It may be that iron was allowed an important role in this ceremony because of the association of iron with meteorites, powerful natural phenomena whose own inherent power might increase the potency of the ritual.
We also know that iron dagger blades were important enough to be mentioned in diplomatic correspondence. The best-known example is a letter from King Tushratta of Mitanni (today in northern Iraq and Syria) detailing a dowry of his daughter who was to be sent as a bride to Tutankhamun's grandfather, king Amenhotep III. This letter intriguingly refers to a dagger blade of "habalkinu", a poorly documented word derived from the ancient Hittite language which some linguists have translated as "steel".
Only further detailed analysis of the chemistry and microstructure of other artefacts will tell us if meteorites were a common source of the iron that the ancient Egyptians produced. We also need to determine when where and how the smelting of terrestrial iron ores started in Egypt to further guide us in our knowledge on the origins, evolution and specific techniques of ancient Egyptian metalworking technology. By combining this with our knowledge of the cultural importance of iron, we can start to develop a realistic understanding of the true value of this metal in ancient Egypt.