Although it is generally assumed that early iron objects were produced from meteoritic iron, such origin of the blade has long been the subject of debate, and previous analyses yielded controversial results.
Now dramatic technological improvements have allowed the researchers to determine the composition of the blade.
"Meteoric iron is clearly indicated by the presence of a high percentages of nickel," main author Daniela Comelli, at the department of Physics of Milan Polytechnic, told Discovery News.
Indeed, iron meteorites are mostly made of iron and nickel, with minor quantities of cobalt, phosphorus , sulfur and carbon.
While artifacts produced with iron ore quarrying display 4 percent of nickel at most, the iron blade of King Tut's dagger was found to contain nearly 11 percent of nickel.
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Further confirmation of the blade's meteoric origin came from cobalt traces.
"The nickel and cobalt ratio in the dagger blade is consistent with that of iron meteorites that have preserved the primitive chondritic ratio during planetary differentiation in the early solar system," Comelli said.
Comelli and colleagues also investigated the possible source of the iron blade.
"We took into consideration all meteorites found within an area of 2,000 km in radius centered in the Red Sea, and we ended up with 20 iron meteorites," Comelli said.
"Only one, named Kharga, turned out to have nickel and cobalt contents which are possibly consistent with the composition of the blade," she added.
The meteorite fragment was found in 2000 on a limestone plateau at Mersa Matruh, a seaport some 150 miles west of Alexandria.
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The study shows the ancient Egyptians attributed great value to meteoritic iron for the production of precious objects, possibly perceiving those chunks of iron falling from the sky as a divine message.
The most ancient Egyptian iron artifacts, nine small beads excavated from a cemetery along the west bank of the Nile tomb in Gerzeh and dated about 3200 BC, are also made from meteoritic iron hammered into thin sheets.
"It would be very interesting to analyze more pre-Iron Age artifacts, such as other iron objects found in King Tut's tomb. We could gain precious insights into metal working technologies in ancient Egypt and the Mediterranean," Comelli said.
She noted that the high quality of King Tut's dagger blade shows that iron smithing was successful already in the 14th century B.C.
The dagger blade is not the only celestial object found in the boy king's tomb. His pectoral, or necklace, features an amulet scarab which is not "greenish-yellow chalcedony," as Carter had noted, but Libyan desert silica glass.
The glass was produced by the impact on the sand of a meteorite or comet. Such natural glass exists only in the remote and inhospitable Great Sand Sea of Egypt -- the Western Desert. In order to produce the scarab, the ancient Egyptians would have had to trek across 500 desert miles.
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