The metallurgical texture of gold artefacts found at the Bronze Age rampart of Bernstorf (Bavaria) studied by neutron diffraction

Abstract

The metallurgical texture of several of the gold artefacts found in 1998 at a Bronze Age fortification near Bernstorf in Bavaria was studied by neutron diffraction using the STRESS-SPEC instrument at the FRM II reactor of the Maier-Leibnitz Centre of the Technical University of Munich. The pieces consist of approximately 0.1 mm-thick gold sheets embossed with ornamentations. The purpose of the texture studies was to obtain information on the technique used to produce the thin gold sheets. All studied spots with about 5 mm diameter on the artefacts were found to exhibit a cube type {100}〈001〉 texture that is typical for many cold rolled and subsequently annealed and recrystallized face centred cubic metals. A cube texture similar to that of the Bernstorf artefacts was obtained by straight rolling followed by annealing at different temperatures and for different periods of time, but never with the purity observed in two of the Bernstorf artefacts. This leaves some uncertainty about the manner in which the Bernstorf objects were made. By comparison with laboratory-made reference samples, one can rule out hammering or cross-rolling with or without subsequent annealing for the manufacture of the gold foils. Beyond the interest in these results for the discussion of the authenticity of the Bernstorf gold finds, texture determinations using neutron diffraction are shown to be a non-destructive method for obtaining information on the techniques used to produce archaeological gold artefacts in general.