Research carried out on the Staffordshire Hoard has revealed that Anglo-Saxon goldsmiths were sophisticated enough to make gold appear more golden.
In the largest study of its kind ever undertaken on Anglo-Saxon gold, 114 objects from the Staffordshire Hoard were taken to the British Musuem, where they were tested along with 36 items from the museum’s own collections. Hundreds of microscopic analyses of the gold metal were made using XRF [X-ray fluorescence] and SEM-EDX [scanning electron microscopy with energy dispersive X-ray spectroscopy] technology. These techniques allow the exact elemental composition of the Anglo-Saxon gold objects to be ascertained: most gold objects modern and ancient are in fact alloys, containing a variable percentage of other metals, usually copper and silver (the ‘carat’ rating of gold refers to this: 18 carat gold is 75% gold; 25% other metal). The Staffordshire Hoard objects have a high gold content, but they’re still alloys.
The scientific analysis has revealed that Anglo-Saxon goldsmiths knew how to treat gold objects to improve their colour and make them appear ‘more gold’ by removing alloyed metals such as copper and silver from the surface of the objects. This is the first study to show this technique being widely used in the Anglo-Saxon period.
“We had no idea they were doing it,” said Dr Eleanor Blakelock, who carried out the tests.“Previously, we had just done analyses of the surfaces of objects – because we didn’t suspect that the Anglo-Saxon goldsmiths were deliberately removing the silver content from the surfaces of gold artefacts.”
Relatively little is known about Anglo-Saxon goldsmithing, but achieving this surface treatment would have been a skilled task. Furthermore, the researchers still don’t know how they did it – their process to make it more golden remains a secret.
The study appears to suggest that male items of personal adornment, such as buckles and clasps, were made with a higher gold content than female items, such as jewellery, and that the latter were instead more heavily surface treated to improve their colour.