When archaeologists first examined the mummy of King Tutankhamun in 1925, they found two beautiful daggers in the pharaoh’s linen wrappings. One had a gold blade, and the other was made of iron. A new study confirms what archaeologists have long suspected: Artisans crafted King Tut’s iron dagger from a meteorite.
The new analysis suggests that ancient Egypt came late to using iron on a large scale, an expert in ancient metallurgy said. What’s more, that tardiness may have led to military defeats at the hands of rival civilizations that had already equipped their soldiers with iron weaponry.
More Precious than Gold
Many ancient people valued iron more than gold. Because iron has a high melting point (1538°C), early smiths couldn’t heat ore enough to extract iron, nor could they forge the iron into weapons. Ordinary people had to rely on “bronze, and previously copper [to make tools and weapons for common people]. Gold and iron objects in that period were mainly for ornamental purposes—for gifts and so on,” said Daniela Comelli, a materials scientist at the Polytechnic University of Milan, in Italy, who is the lead author of the new study of the dagger.
Metalworkers commonly chose bronze, which is a copper-tin alloy, for making swords, spears, and tools, because its constituent metals were easier to mine, refine, and work with. However, the Egyptians had a source of iron that was easy to work with, although difficult to acquire: meteorites. Those extraterrestrial rarities contained iron plus other elements, including 10-30% nickel. Even though craftsmen couldn’t melt meteorites, they could hammer them into beads, or into weapons like Tutankhamun’s dagger, Comelli said. Few iron objects from ancient times remain today, partly because of loss from corrosion.
X-ray Fluorescence Reveals Blade Composition
In the new study, published in the May issue of Meteoritics and Planetary Science, Comelli and her colleagues describe how they used a portable X-ray fluorescence (XRF) machine to examine the dagger at the Egyptian Museum of Cairo. The interdisciplinary team bombarded the knife with X-rays and looked at the radiation emitted by the metal in response. Each element in the blade gave off different wavelengths of radiation, allowing the scientists to determine its composition.
The results indicated that the dagger contains substantial amounts of nickel and cobalt. Interpretation of the XRF measurements by scientists at the University of Pisa, in Italy, showed that the dagger’s composition matched well with the compositions of 11 iron-bearing meteorites analyzed in the same way. To confirm the validity of the instrument’s measurements, the team also used the device to analyze 11 samples of stainless steel with known percentages of constituent elements.
Previous studies have shown that iron made from mined iron ores prior to the nineteenth century contains less than 4% nickel, by weight. The team measured more than 10% nickel in the dagger, providing further evidence that it was made from meteorite metal rather than terrestrial ore.
In 1994, another team used X-ray fluorescence, which leaves the blade unharmed, to ascertain King Tut’s dagger’s composition. The dry conditions in Tutankhamun’s tomb, which prevented the dagger from rusting, made it possible to use the technique for analyzing the composition of the blade’s still-pristine surface. Researchers have shunned using any sort of destructive techniques to analyze the composition of the precious object.
The 1994 analysis concluded that the metals in Tutankhamun’s blade did not match those in most iron meteorites. However, Comelli and her collaborators report in their paper that they used a newer, more accurate instrument to retest the blade.
“No one ever really doubted the meteoritic origin of that dagger,” said Thilo Rehren, an archaeometallurgist at University College London, Qatar, in Doha, who was not involved with the study. “It was the logical thing to assume. The beauty of this [new] paper is that they’ve put it beyond doubt that this is meteoritic iron,” he added.
Iron Still Rare in King Tut’s Egypt
The new results strengthen historians’ long-held suspicion that, during Tutankhamun’s short reign (1332–1323 BCE), Egypt had yet to smelt and forge its own iron, Rehren said. Ancient Egyptians and neighboring cultures already referred to all kinds of iron at the time as “iron of the sky,” Comelli and her coauthors note.
Ancient Egypt was “rather slow to take up iron as the metal of choice,” said Rehren, since Egypt lacked both iron deposits and large numbers of trees to fuel smiths’ fires. Iron weapons and tools in Egypt did not become common until between 700 and 800 BCE. Egypt’s slowness came at a price. Because iron weapons were harder and more durable, Egypt fell much more easily during battles with the Hittites and the Nubian Kingdom of Kush—both of which had issued iron weapons to their soldiers, while Egypt was still using bronze, Rehren said.
Determining the origin of the dagger and other iron objects from ancient Egypt will help scientists build a broader picture of ancient metallurgy there and in neighboring regions, according to Rehren. Comelli added that she hopes to get permission from the Egyptian Museum of Cairo, where the dagger is kept, to probe the artifact to find out more about the meteorite that it was made from.
—Elizabeth Deatrick, Writer Intern; email: [email protected]
Correction, 10 June 2016: An earlier version of this article incorrectly credited the photo and also omitted a university team’s contribution to the research. The article has been updated to correct these inaccuracies.