In 79 CE, Mount Vesuvius erupted, destroying the Roman city of Herculaneum.
Thousands of people were killed instantly. Now, scientists have made a shocking discovery—inside the skull of one victim, they found a dark, glass-l
ike material that appears to be their fossilized brain.
This rare finding, published in Scientific Reports, suggests that the person’s brain turned to glass due to extreme heat from the volcanic eruption.
Normally, glass does not form easily because it requires rapid cooling from a liquid state without crystallizing.
Organic glass—made from biological material—is even rarer because it needs incredibly high temperatures followed by sudden cooling.
The victim, discovered in a building called the Collegium Augustalium, was lying in bed when they died.
Researchers led by Guido Giordano analyzed the glassy remains inside the skull and spinal cord using X-ray and electron microscopy.
They found that the brain must have been exposed to temperatures above 510°C (950°F) before cooling rapidly.
However, the pyroclastic flows—fast-moving currents of hot gas and ash—that buried Herculaneum were not hot enough to explain this process, as they only reached about 465°C.
So, how did the brain reach such extreme heat?
Scientists believe that a super-heated ash cloud hit Herculaneum before the pyroclastic flows arrived.
This deadly cloud would have raised the victim’s body temperature past 510°C almost instantly before cooling just as quickly when the cloud disappeared.
The skull and spine bones likely shielded parts of the brain from complete destruction, allowing it to turn into glass instead of burning away entirely.
This discovery sheds new light on the violent eruption of Mount Vesuvius and the terrifying speed at which its effects unfolded.
It also raises new questions about how heat interacts with human remains in extreme conditions. Finding fossilized brain tissue is already rare, but discovering it transformed into glass makes this case one of a kind.
The tragic death of this ancient Roman has now helped scientists better understand how volcanic eruptions can instantly affect the human body.
More research may uncover similar cases, but for now, this Herculaneum victim holds a unique place in history—forever preserved in glass.
