by guest blogger: Isadora Fontaine
Deep in the Predynastic galleries of the Petrie Museum, there is something truly out of this world.
In the cabinet containing jewellery and beads from a tomb in Gerzeh, a site about 70km from Cairo, there are three iron beads. They may not look like much, they are small, blackened and corroded and placed among more colourful artefacts, but these are no ordinary beads…they are made from a meteorite. At over 5,000 years old, they are the oldest man made iron objects in history.
Professor Thilo Rehren from UCL made the discovery that proved the extraterrestrial origins of the iron beads, which are not made from pure iron but an iron-nickel alloy. This natural alloy is common in meteorites but the research team needed further proof. By scanning the beads with gamma rays and neutron beams, Thilo and his research team discovered unusually high amounts of cobalt, germanium and phosphorus. This was the proof that the metal really did originate in space, as these trace elements are found in higher concentrations in meteoric iron than in iron ore.
The beads also show the earliest examples of blacksmithing: instead being carved or drilled like other beads, the iron was heated before being hammered and rolled into shape, then cooled extremely slowly to prevent the metal from cracking.