Researchers have found that a dull bracelet and a rusty hollow hemisphere decorated with gold were forged not with metal from the ground but with iron from meteorites that fell from the sky.
The discovery, led by the now-retired head of conservation at Spain's National Archaeological Museum, Salvador Rovira-Llorens, was revealed in a paper published in January, and suggests that metalworking technology and techniques were much more advanced than we thought in Iberia more than 3,000 years ago.
The Vilena hoard, as the cache of 66 mostly gold objects is known, was discovered more than 60 years ago in 1963 in what is now Alicante in Spain and has since been considered one of the most important examples of Bronze Age goldsmithing on the Iberian Peninsula and throughout Europe.
Determining the age of the collection is somewhat difficult, however, thanks to two objects: a small hollow hemisphere thought to be part of a sceptre or sword hilt, and a bracelet resembling a torc. Both have what archaeologists describe as an "iron" appearance - that is, they appear to be made of iron.
On the Iberian Peninsula, the Iron Age did not begin until around 850 BC. The problem is that the gold materials are dated between 1500 and 1200 BC. So identifying the location of what appear to be iron artifacts in the context of the treasure from Vilna is something of a mystery.
But iron ore from the earth's crust is not the only source of malleable iron. There are a number of pre-Iron Age iron artifacts around the world that were forged from material from meteorites. Perhaps the most famous is the dagger made of meteoritic iron of the pharaoh Tutankhamun, but there are other Bronze Age weapons made from this material, and they were very highly prized.
There is a way to tell the difference: iron from meteorites has a much higher nickel content than iron dug from the earth's soil. So the researchers got permission from the Vilna Municipal Archaeological Museum, where the collection is housed, to carefully test the two artifacts and determine how much nickel they contained.
They carefully sampled both artifacts and subjected the material to mass spectrometry to determine their composition. Despite the high degree of corrosion that altered the elemental composition of the artifact, the results strongly suggested that both the hemisphere and the bracelet were made of meteoritic iron.
This solves the dilemma of how the two artifacts fit with the rest of the collection: they were made during the same period, dating from around 1400-1200 BC.
"The available evidence suggests that the hat and bracelet from the Vilna hoard would currently be the first two objects attributed to meteoric iron on the Iberian Peninsula," the researchers explain in their paper, "which is consistent with a Late Bronze Age chronology, before the onset of widespread terrestrial iron production."
Because the objects are highly corroded, the results are inconclusive. But there are newer, non-invasive techniques that could be applied to the objects to produce a more detailed data set that would help to solidify the findings, the team suggests. | BGNES
