On that fateful day in 79 CE when Mount Vesuvius rained hell on the Roman towns of Herculaneum and Pompeii, the intense burst of heat turned one poor soul’s brain into glass. Literally.
Back in the 1960s, archaeologists discovered the remains of a human in the ruins of Herculaneum lying on a wooden bed and smothered in volcanic ash. Reporting their findings in The New England Journal of Medicine, Italian researchers from the University of Naples Federico II studied the contents of this person’s skull and discovered a shiny black shard of glass.
They argue the material is brain tissue that has been burned at an extremely high temperature and undergone a process called vitrification. Typically, brain tissue is extremely rare to find during archaeological work because it is quick to decompose. In certain situations, brain tissue can be somewhat preserved as the tissue’s fats get converted to glycerol and fatty acid salts, effectively turning into soap.
In this case, however, the tissue was subjected to such an intense temperature, perhaps as high as 520°C (968°F), that it became vitrified. This is the process when a substance is transformed into a glass, usually through exposure to scorchingly hot temperatures.

There were several clues suggesting this was genuinely vitrified brain tissue, not simply a misplaced jewel. For starters, the glass contains several proteins that you can find in human brain tissues. The researchers also detected fatty acids found in human hair grease within the material. Finally, there was no trace of any other similar glassy material anywhere else on the body or around the site.
The researchers say this discovery is “unique” and appears to be the first time this has been seen in an archaeological context. However, they note that similar reports of glass brains were seen among victims of the bombing of Dresden in World War II. Over just three days in February 1945, British and American planes dropped around 3,900 tons of explosives on the German city, creating a firestorm that killed around 25,000 people.
Herculaneum wasn’t the only victim of Mount Vesuvius in 79 CE. The catastrophic eruption also destroyed the nearby Roman cities of Pompeii, Oplontis, Stabiae, and several other smaller settlements. As you can imagine, this resulted in thousands upon thousands of horrific deaths. Many were smothered in volcanic ash, some choked to death on searingly hot gas, and others were instantly vaporized by the rush of heat.
Another new study, released today, found that hundreds of people in Herculaneum most likely became trapped inside boat houses, where they slowly but surely were “baked” alive.