Tests have now shown that at least one bead of jewelry from an Egyptian tomb was made from a meteorite.
The tube-shaped bead is one of nine found in 1911 in a cemetery at Gerzeh, around 70 kilometres south of Cairo. The cache dates from around 3,300 BC, making the beads the oldest known iron artefacts in Egypt.
An early study found that the iron in the beads had a high nickel content — a signature of iron meteorites — and led to the suggestion that it was of celestial origin2. But scholars argued in the 1980s that accidental early smelting efforts could have led to nickel-enriched iron3, while a more recent analysis of oxidised material on the surface of the beads showed low nickel content4.
To settle the argument, Diane Johnson, a meteorite scientist at the Open University in Milton Keynes, UK, and her colleagues used scanning electron microscopy and computed tomography to analyze one of the beads on loan from the Manchester Museum, UK. The researchers weren’t able to cut the precious artefact open, but they found areas where the weathered material on the surface of the bead had fallen away, providing what Johnson describes as “little windows” to the preserved metal beneath.
The nickel content of this original metal was high — 30% — suggesting that it did indeed come from a meteorite. To confirm the result, the team observed a distinctive crystallographic structure called a Widmanstätten pattern. It is only found in iron meteorites, which cooled extremely slowly inside their parent asteroids as the Solar System was forming.
