ROMANO‐EGYPTIAN RED LEAD PIGMENT: A SUBSIDIARY COMMODITY OF SPANISH SILVER MINING AND REFINEMENT*

Samples of red pigment from a group of seven Roman‐period Egyptian mummies, known as red‐shroud mummies, are investigated. Elemental analysis by inductively coupled plasma time‐of‐flight mass spectrometry (ICP–TOFMS) shows that the samples contain mostly Pb (83–92% by weight), along with 0.2–2.0% Sn. All of the samples are found to have similar trace element distributions when normalized to the continental crust, suggesting that they share a common geological origin. Lead isotope ratios are found to match the mixed lead sources typically associated with Rio Tinto, Spain – a site extensively mined for silver during the first century ad . Raman microspectroscopy identifies the major phase of each sample to be red lead (Pb₃O₄) with a minor phase of lead tin oxide (Pb₂SnO₄). Lead tin oxide does not occur naturally, and its incidental occurrence within the sample indicates that the material was heated under oxidative conditions at temperatures in excess of 650°C. In archaeological contexts, the high‐temperature oxidative treatment of lead is typically associated with metallurgical refinement processes such as cupellation. Based on this evidence, it is argued that the pigment was produced out of litharge associated with silver cupellation at the Rio Tinto site.