A rare and haunting discovery inside the skull of a Roman man who perished in the eruption of Mount Vesuvius has revealed his brain was transformed into glass—fossilised by an intense surge of heat and ash.
An international team of researchers analysed the dark, glass-like substance found within his skull, determining that it was vitrified brain tissue—a result of extreme temperatures followed by rapid cooling.
The victim, believed to have been in his twenties, was first uncovered by archaeologists in 1960. However, the unusual black glass remained unnoticed until recently.
He was found lying on his bed inside the Collegium Augustalium, a building in the ancient Roman town of Herculaneum that belonged to an imperial cult dedicated to Emperor Augustus.
Like Pompeii, Herculaneum was obliterated when Vesuvius erupted in 79 AD. However, while Pompeii was buried under thick layers of volcanic ash and pumice, Herculaneum was struck by searing pyroclastic flows—deadly torrents of gas and debris capable of incinerating everything in their path.
The study’s findings, published in the science journal Nature, suggest that before these pyroclastic flows reached the town, a superheated ash cloud surged through Herculaneum.
This brief but extreme wave of heat, estimated to have exceeded 950°F (510°C), was likely responsible for vitrifying the brain tissue—an effect that would not have been possible under the lower temperatures (around 869°F or 465°C) of the later pyroclastic flows, which cooled more gradually.
Glass rarely forms in nature due to the precise conditions required: molten material must cool so quickly that it does not develop a crystalline structure. The temperature shock necessary for this process explains why the victim’s brain, exposed to the initial thermal blast, transformed into a glass-like fossil.
“Only later in the night was the city completely buried by deposits from the pyroclastic flows,” explained volcanologist Professor Guido Giordano of Roma Tre University.
“This scenario is crucial not just for historical and volcanological reconstruction, but also for modern civil protection. It highlights the lethal danger of even diluted pyroclastic surges, which may not cause structural damage but can be fatal due to their intense heat.”
Dr PierPaolo Petrone, a forensic anthropologist at the University of Naples Federico II, emphasised the unprecedented nature of this discovery: “A vitrified brain and spinal cord like this has never been found among the hundreds of victims of the 79 AD eruption—or anywhere else in the world.
“The unique conditions at the moment of the eruption, combined with the protection offered by the skull and spinal column, likely preserved the organic material long enough for this extraordinary transformation to occur.”
