The boy’s body was preserved in a copper coffin, taking on a green hue.

An adolescent boy, interred in a copper coffin almost three centuries ago in northern Italy, stands out as the only nearly fully preserved green mummy known to exist.

While other ancient remains have shown partial mummification or green coloration from burial alongside copper or bronze items, a green mummified hand of a newborn clutching a copper coin was discovered in medieval Hungary within pottery vessels.

In contrast, this Italian mummy is largely intact, save for its feet, showcasing an almost entirely green complexion from skin to bone, with the exception of its left leg.

The mummy emerged from the basement of an old villa in Bologna in 1987, where it underwent forensic analysis at the University of Bologna. Experts determined it belonged to a boy aged 12 to 14, and it has been preserved at the university since.

Annamaria Arabiso, a conservation scientist at the University of Rome Tor Vergata, took part in the examination alongside a myriad of specialists including geneticists, anthropologists, radiologists, mathematicians, physicists, and computer scientists. “It was an impressive interdisciplinary effort,” she remarks.

The researchers conducted an extensive series of chemical and physical analyses on the mummy. Radiocarbon dating assigned the boy’s death to between 1617 and 1814, with Arabiso noting that the remains exhibited no apparent signs of trauma or disease.

Copper played a crucial role in preserving both hard and soft tissues, owing to its known antimicrobial characteristics, Arabiso states. However, the copper box reacted with acid from the body, leading to corrosion that created copper byproducts interacting with the chemicals in the bone. Gradually, copper ions replaced calcium in the boy’s skeleton, imparting a green hue and simultaneously enhancing the structural integrity of his bones over time.

The skin developed a rough layer of copper corrosion products referred to as patina, a pale green film typical on bronze items. Arabiso explained that this patina formed as a result of copper’s reaction with water and carbon dioxide during decomposition.

“This fundamentally shifts our understanding of heavy metals, revealing a more intricate relationship regarding their effects on conservation than previously assumed,” she states.

Possibly due to acidic interactions, the bottom of the copper box eventually cracked, leading to liquid spillage that left the remains in a cool, arid environment with limited oxygen, which mitigated decomposition. Arabiso suggests the boy may have become disoriented and lost his footing during this process.

“Engaging with these extraordinary human remains was profoundly emotional for me,” she shares.

Julia Gallo, having seen images of mummies for the first time at the Collège de France in Paris, expressed her awe. “Oh, how beautiful!” she exclaims. “This entire case study is utterly captivating.”

Gallo offered praise for the researchers’ efforts in meticulously investigating the physical and chemical processes leading to the mummification and subsequent color changes. “The evidence robustly supports their conclusions regarding both the preservation of tissues and bones and the variations in coloration.”

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