Scientists have discovered the reason behind the transformation of a young man’s brain to glass following the eruption of Mount Vesuvius in Italy in 79 AD.

In 2020, the researchers found the black, glassy substance inside the victim’s skull and spinal cord. Now, a study has stated that the formation of the glass in the victim’s brain could be because of fossilised brain tissue.

Guido Giordano, a volcanologist at Roma Tre University in Rome and lead author of the study, stated that the person’s body tissue must have been heated to above 950 degrees Fahrenheit before cooling rapidly and transforming into glass. The process is called vitrification. 

“Obsidian glass, that is, volcanic glass, forms when lava is very quickly cooled, for example, where it enters into water,” Mr Giordano added.

According to scientists, the pyroclastic flows, which consist of fast-moving volcanic material and hazardous gas from Mount Vesuvius, were not hot enough to convert the victim’s brain into glass.

Scientists state that these flows reached a maximum temperature of 465 degrees Celsius and cooled down too slowly for vitrification to happen.

Rather, researchers think the person’s brain may have vitrified because of a short but highly hot ash cloud at the time. Some scientists, however, remain doubtful since soft tissue must be exposed to extremely particular circumstances before it can become glass.

The young man’s spine and skull likely prevented the heat from destroying his brain entirely, allowing some of it to change into a unique substance that looked like glass.

Archaeologists unearthed the charred remains of the victim in the 1960s, who was said to be around 20 years old during the volcanic eruption. They found the victim’s skull in the coastal town of Herculaneum.

However, in 2018, Italian anthropologist Pier Paolo noticed something shiny inside a man’s skull and started investigating it. That’s when they found out the victim’s brain had turned black and had glass-like pieces, which is extremely rare.

Previous research has shown that neurons and proteins in the individual’s brain were preserved, said Giordano. The discovery has the potential to change quite a few theories about the impact and sequence of events during the Mount Vesuvius eruption.