The origins of mercury gilding

A survey of almost 50 gilded objects in the British Museum has traced the occurrence of the mercury gilding technique from the later Roman and Sasanian Empires of the third and fourth centuries AD to the late Chou period in China of the third century BC. The technique appears to have been unknown during the Hellenistic period and under the Roman Republic and early Empire. Mercury gilding was identified by microscopic examination and qualitative emission spectrographic analysis.