Neutrons have allowed a peek inside a medieval necklace that scientists have been unable to open

In 2008, a beautiful 800-year-old gold necklace was found in a medieval dump in the old city of Mainz. It was noticed at the time that the pendant was equipped with an opening mechanism, however For years, scientists have not been able to open it. Now, thanks to modern imaging techniques and the use of a Heinz Maier-Leibnitz (FRM II) neutron source at the Technical University of Munich, scientists have been able to look inside the monument. They found small pieces of bone in it.

Conservator Matthias Heinzel spent 500 hours cleaning and maintaining the monument. By the eyelet that was used to hang the ornament, he noticed a piece of cloth, which he later identified as silk. This is the first evidence in history that such pendants could be tied around the neck with a silk ribbonsays the expert. Thanks to the FRM II, it was possible to measure the thickness of the thread and the density of the fabric. While working, Heinzel noticed that the pendant, which measured 6 by 6 cm and 1 cm thick, was probably a cooking pot. However, x-rays did not give an answer to the question whether there was anything inside. We had to wait many years for appropriate search technologies to appear.

The non-destructive source of neutrons was very useful because we could not open the mechanism and look inside. The entire mechanism is badly damaged by corrosion and opening the pendant will destroy itHeinsell explains.
Thanks to the neutron study, we know that every piece of bone in the reliquary was wrapped in cloth. Scholars cannot tell if the bones belonged to a saint, and if so, which ones. A part of the manuscript with the saint’s name is usually attached to the reliquary but here we do not note itsays the restorers, adding that the main task is to preserve the relics for future generations.

Scholars date the monument to the late 12th century and believe it was created in a workshop in Hildesheim in Lower Saxony. The reliquary is made of gilded copper and decorated with enamel depicting Jesus, the Evangelists, Mary and four holy women.

Bone Ordnance Pendant