How can you tell if an ancient knife, arrowhead, or pharaoh's dagger was made with iron from space? For a long time, one of the clearest clues lay in the metal itself: a striking crystal pattern known as Widmanstätten. But a new experiment suggests that ancient blacksmiths may have unknowingly erased this extraterrestrial trace.
The question has a famous protagonist: Tutankhamun's iron dagger, which Howard Carter found in the Valley of the Kings in 1922. The metal in its blade didn't originate on Earth; it arrived from space inside a meteorite and, more than 3,000 years ago, was transformed into a weapon.
Previous studies, like one in Meteoritics & Planetary Science, determined that the blade contains about 11 percent nickel and 0.6 percent cobalt, a composition that confirmed the iron's extraterrestrial origin.
Now, a new study, published in the journal Archaeometry, casts doubt on one of the clues used to reconstruct how the dagger was made.
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Forging Meteoric Iron
Researchers found that when meteoric iron is heated and forged between 1,472 and 1,562 degrees Fahrenheit (800 to 850 degrees Celsius), the Widmanstätten pattern disappears completely. At slightly lower temperatures, between 1,112 and 1,202 degrees Fahrenheit (600–650 degrees Celsius), it also begins to change.
Explore All OptionsThe study, led by a researcher from the National University of San Juan in Argentina, also revisits a question that has long surrounded the boy pharaoh's dagger: at what temperature was it forged? If the structure observed on its blade is indeed similar to the Widmanstätten pattern, the results call into question the theory that the dagger was forged at temperatures between 1,472 and 1,742 degrees Fahrenheit (800 to 950 degrees Celsius), as previous studies have suggested.
To preserve such a structure, the metal would have had to be worked at considerably lower temperatures.
And here a consequence emerges that goes far beyond the Egyptian dagger. The fact that an ancient iron object doesn't retain that characteristic crystal pattern doesn't necessarily mean it wasn't made from a meteorite. The blacksmith's own hand could have erased the evidence.
“Many archaeological iron objects with high nickel and cobalt content, but without a visible Widmanstätten pattern, such as certain arrowheads, knives, or ornaments from the Late Bronze Age and Early Iron Age, could have been forged at temperatures that erased the Widmanstätten,” Laura Noel García, a Ph.D. in Engineering Sciences and a specialist in archaeometallurgy, told Discover. “These artifacts deserve to be reanalyzed.”
The Widmanstätten Pattern In Meteoric Iron
Iron meteorites account for only a small percentage of observed meteorite falls. They are not simply blocks of metal: they are composed primarily of an iron-nickel alloy, along with small amounts of other elements, such as sulfides and phosphides, and cooled extremely slowly inside the asteroids from which they originated.
During this cooling process, which could have taken place over millions of years, the atoms rearranged themselves to form different phases of the alloy, including kamacite and taenite. The result, visible when the meteorite is cut and polished, is a network of bands that intersect at well-defined angles. This is the Widmanstätten pattern — named after Count Alois von Widmanstätten — one of the most striking and easily recognizable features of metallic meteorites.
But there's a problem. This structure formed under conditions that no longer exist once the meteorite reaches Earth. Heat can alter or destroy it. And that is precisely what the researchers wanted to find out.
To do so, García and her team turned to an octahedrite, a type of iron meteorite, and an unlikely ally for a materials science experiment: a Spanish blacksmith specializing in making Damascus steel knives.
The team took samples of the meteorite and subjected them to three temperature ranges: 1,112 to 1,202 degrees Fahrenheit (600–650°C), 1,472–1,562°F (800–850°C), and 2,012–2,102°F (1,100 to 1,150 degrees Celcius). In each case, the samples were heated and hammered to reduce their thickness, mimicking, as far as the experiment allowed, a traditional forging process.
Then came the crucial part. The researchers analyzed the samples to find out what had happened to their internal structure. It wasn't enough to see whether the pattern was still visible to the naked eye; to determine whether the Widmanstätten pattern truly persisted, they also had to study how the crystals were arranged.
Analyzing King Tut’s Meteorite Dagger
To do this, they used a technique called Electron Backscatter Diffraction (EBSD), which allows researchers to analyze the crystallographic orientation of materials.
The result was clear: in the samples forged between 1,472 and 1,562 degrees Fahrenheit, the characteristic crystallographic structure of the pattern had completely disappeared. In those subjected to temperatures between 1,112 and 1,202 degrees Fahrenheit, however, the original structure had begun to change but had not completely disappeared. At temperatures between 2,012 and 2,102 degrees Fahrenheit, the transformation was even more pronounced.
“When we study the samples we forged at that temperature, we see that there is no Widmanstätten pattern, that the crystallography doesn't show a particular relationship, which is what we would expect to find if there were a Widmanstätten pattern; instead, it is completely destroyed,” García said.
And here, Tutankhamun's dagger appears. In 2022, Takafumi Matsui, director of the Planetary Exploration Research Center at the Chiba Institute of Technology in Japan, and his colleagues analyzed the blade using non-destructive techniques. Nickel distribution maps showed discontinuous bands arranged in a pattern that, according to the researchers, suggested a Widmanstätten pattern. Based on this structure and other evidence, they estimated that the dagger had been worked at temperatures below 1,742 degrees Fahrenheit and concluded that it had been manufactured by low-temperature hot forging.
García reaches a different conclusion. If the structure identified by Matsui and his colleagues does indeed correspond to a Widmanstätten pattern, the experiments in the new study indicate that it could not have been preserved after forging at 1,472 to 1,562 degrees Fahrenheit. For that structure to survive, the working temperature would have had to be considerably lower.
“We believe that the limitations in the techniques available for studying artifacts that cannot be removed from museums can lead to conclusions that are not entirely supported by the evidence,” García said. “Archaeologists should not be guided solely by this pattern.”
One of García’s next lines of research will be to expand the experiments and, eventually, use computational models to test a wider range of compositions and temperatures.
A New Way To Read Ancient Weapons
In parallel, she is searching for Latin American objects that will allow her to bring these questions from the laboratory to archaeological collections. In Argentina, she is reviewing pieces associated with the Campo del Cielo meteorite, the massive fall that occurred some 5,000 years ago in what is now Argentine territory, including bolas made from its fragments.
She is also in contact with researchers at the National Museum of Brazil in Rio de Janeiro and is reviewing museum collections in Bogotá that contain objects believed to be made of meteoritic iron.
The idea is to determine not only whether these objects were indeed made from extraterrestrial material, but also what technology was used by those who crafted them. A piece simply hammered cold tells a very different technological story from one that was heated and forged: the latter would imply a greater understanding of the metal's behavior and, above all, the ability to control temperature.
Read More: Thousands Of Meteorites Hit Earth Each Year — Here's What They Bring
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a study published in Meteoritics & Planetary Science: The meteoritic origin of Tutankhamun's iron dagger blade
- This article references information from a study published in Archaeometry: Compositional, Microstructural, and Microtextural Evolution of an Octahedrite Iron Meteorite During Experimental Forging: Implications for Archaeometallurgy
Thousands Of Meteorites Hit Earth Each Year — Here's What They Bring
