Ancient Egyptian Iron Beads Got Their Start in Outer Space

We can typically trace the production of iron from ore to an era fittingly called the Iron Age, roughly between 1300 and 700 BC. But archaeologists have found iron artifacts that predate the Iron Age. Specifically, they found nine beads, each less three-quarters of an inch long, that have been dated at around 3200 BC.

So how did iron beads come to exist centuries before iron became a prevalent metal? A new study found evidence that the iron that made these ancient beads came from space. More specifically, the paper, published in the Journal of Archaeological Science, suggests that early metalworkers used iron found in meteorites.

Iron can be a tricky metal to deal with in the context of artifacts because all iron doesn’t come from ore. Iron can be a by-products of copper smelting; it can be meteoric iron, which is to say, iron that came from space; or it can happen that ‘younger’ iron somehow makes its way into an older archaeological site contaminating it. There are some minerals, like magnetite, that are easy to mistake for corroded iron. And it gets trickier because iron is hard to test non-invasively, meaning without cutting the object. And cutting 5,000 year old beads is pretty much out of the question.

The ancient beads are tubular, and were found in two separate ancient burial sites. Seven were found in one tomb, three arranged on the deceased’s waist and four arranged on a necklace, and the last two beads were found in a separate site near the corpse’s hands. Both sites were sealed, which made dating them and the iron beads easy. But explaining how they got there was another matter. These nine little beads seemingly occupy a unique, and strange, place in the history of metal use.

“The shape of the beads was obtained by smithing and rolling, most likely involving multiple cycles of hammering, and not by the traditional stone-working techniques such as carving or drilling which were used for the other beads found in the same tomb," lead author Professor Thilo Rehren of the University College London said in a release.

Complicating the matter further is the simple fact that, as one might expect, all iron isn’t created equally. Meteoritic iron has several characteristics that distinguish it from smelted iron, notably the large crystal grain size. Meteoric iron also has higher concentrations of nickel, cobalt, phosphorus, and germanium. There is also some presence of mineral phases such as schreibersite and rhabdite, cohenite, troilite, and sphalerite in iron that comes to Earth from space.

But the difference between meteoric and smelted iron aren’t exactly definitive. For example, smelted iron with a high concentration of germanium has been found, and nickel and cobalt are common alloying elements in modern iron.

What archaeologists and scientists needed to do with these ancient iron beads was look inside them without damaging them. And a lab in Hungary was able to do just that.

Scientists in Budapest used a sophisticated barrage of instruments to look inside three of these ancient beads: prompt gamma activation analysis, a nuclear analytical technique for non-destructive quantitative determination of elemental compositions; a neutron radiography direct imaging technique; the TOF-ND high-resolution time-of-flight powder diffractometer, which measures the scattering diffraction spectra to differentiate between larger crystallites and powder-like phases; and external milli-beam particle induced X-ray emission spectroscopy.

This barrage of test revealed that the three beads tested—and likely all nine recovered—are tubular in shape with a hole along their long axis. It was impossible to see this with the naked eye due to the metal corrosion clogging the hole. And scientist also determined that the holes were made in the beads, the beads were made around the holes. The way the metal overlaps is consistent with a metal that has been hammered flat and rolled over itself into a bead shape.

But the real great result is in the metallic composition. Scientists were able to measure the corrosion on the beads and work backwards to predict the original composition. The bulk contents of the beads is iron, nickel, and cobalt, and the amounts of each metal are consistent with meteoric iron. They found phosphide crystals that give the metal a phosphorous content typical of meteoritic iron. The amount of phosphorous was actually higher than a piece of corroded meteoric iron the team used as a comparison point, but they chalk the difference up to the beads being in the presence of so much decomposing organic matter, which is both neat and sort of gross.

So there you have it: Ancient iron artifacts that predate the iron age came from space. And it's actually not the first time such a conclusion has been reached: a paper published in May found similar results.