The curious case of the green-colored body: A multidisciplinary investigation of a mummy preserved in a copper-rich environment

A human skeleton exhibiting extensive green coloration and partial mummification was discovered inside a copper-alloy cist beneath an ancient villa in Bologna (Italy). The preservation of bone and soft tissue, together with the green staining, prompted to infer the diagenetic processes that occurred in this unique case during the post-mortem period, analyzing the chemical and structural alterations of the tissues in a copper-rich burial environment. A multidisciplinary analytical approach was employed, by combining Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS). These techniques were applied to both stained and unstained samples of bone and skin in order to characterize their organic and inorganic components, identify potential corrosion products—specifically malachite (Cu₂(CO₃)(OH)₂) and pseudomalachite (Cu₅(PO₄)₂(OH)₄)—and evaluate the role of the burial context—particularly the copper container—in shaping the state of preservation.