Skip to content
  • Home
  • Articles
    • Archaeology & Discoveries
    • Historical Events
    • Artifacts & Treasures
    • Ancient Civilizations
    • Unexplained Phenomena
    • Mythology
  • Subscribe
© Copyright AllThatHistory - 2025
Theme by ThemeinProgress
Proudly powered by WordPress
  • Home
  • Articles
    • Archaeology & Discoveries
    • Historical Events
    • Artifacts & Treasures
    • Ancient Civilizations
    • Unexplained Phenomena
    • Mythology
  • Subscribe
AllThatHistory
  • You are here :
  • Home
  • Unexplained Phenomena
  • How Did a Volcano Turn This Roman’s Brain to Glass?
The formation of glass inside this Roman’s brain could only come from a very specific sequence of events, but this new study has confirmed that it is, at least, possible. Source: UnexpectedToy / Public Domain.
Unexplained Phenomena

How Did a Volcano Turn This Roman’s Brain to Glass?

Allthathistory March 3, 2025

In 79 AD the Roman towns of Pompeii and Herculaneum were destroyed by an enormous volcanic eruption. The devastation caused by the eruption of Vesuvius went on for two days, burying the two towns under superheated ash and mud.

The destructive power of Vesuvius was estimated to be some 100,000 times greater than the atomic bombs dropped on Hiroshima and Nagasaki. Over 20,000 people lived in the area surrounding the volcano, and the remains of over 1,500 have been found to date in the two towns.

Typically it is not entirely fair to call these remains “bodies” as they are rather the hollows in the ash layer where the people fell as they ran for their lives. Over a thousand casts have been made of these bodies, their contorted poses of fear and desperation bringing a grim immediacy to the tragedy.

However not all the bodies were preserved in this way, and the intense heat and pressure caused by the volcanic eruption led to some unusual finds, and some that are downright inexplicable. Perhaps the most famous of these is the man whose brain was turned to glass.

  • The Bronze Age Collapse: A Sudden, Violent Plunge into Darkness
  • The Oxus Civilization, the Kingdom that Vanished
Read moreOumuamua, and Our Search to Reach Our Strangest Visitor.

Yep, you heard that right. Found amidst the bodies in Herculaneum was a young man in his bed in the Collegium Augustalium who had been killed by the eruption. But something had happened at the end which wrought unknown chemical changes in his brain.

The result was not some perfect replica of a human brain made of glass to be sure. However the presence of glassy material inside a human skull is a fact that cannot simply be ignored, and a new study published in Nature from a team led by Guido Giordano of Roma Tre university may just have an explanation.

The body of the man with the glass brain, and the location in Herculaneum where he was found (doi:10.1038/s41598-025-88894-5)
The body of the man with the glass brain, and the location in Herculaneum where he was found (doi:10.1038/s41598-025-88894-5)

First, the facts. We know that glass can form naturally on Earth, under an unusual set of circumstances where liquid cools at a certain rate, is given time to relax and therefore avoids crystallization. Typically this needs to occur for specific temperatures, depending on the composition of the cooling material.

We also know that the human brain can be turned to glass artificially, if you really want to do that sort of thing. But because organic tissues contain liquid water at room temperature this can only work if the brain is cooled to well below freezing. The temperature gap between volcanic magma and freezing water is about as extreme as you can manage on our planet.

Read moreSomething Hiding in the Jungle? The Rock Apes of Vietnam

It should, therefore, be impossible for the eruption of Vesuvius to cause this change. The heat from the ash should have raised the man’s body temperature to the point where the contents of his skull would have returned to soft material, and been burned.

But in this single instance this did not occur. Instead portions of the man’s brain turned to obsidian-like glass. Detailed scans with an electron microscope reveal a network of neurons, axons and other neural structures, perfectly preserved. 

How did this happen? It should, according to our understanding of such things, be impossible; a human brain has never been found preserved in this way before.

The electron microscope scan reveals neural structures perfectly preserved when the brain was turned to glass (doi:10.1038/s41598-025-88894-5)
The electron microscope scan reveals neural structures perfectly preserved when the brain was turned to glass (doi:10.1038/s41598-025-88894-5)

The answer seems to be in the rate at which the body cooled. Most bodies in the eruption were encased in ash from the pyroclastic flows off the volcano, but this one was not. Instead it was exposed to the air and able to cool at a rapid rate.

The team have constructed the most likely scenario that caused this formation. The man was killed by a fast moving, very hot ash cloud which enveloped him but which did not penetrate to the core of his body. However the body was only buried in a few centimeters of ash and, as the cloud dissipated, this allowed for rapid cooling.

This is more than a historic curio. Understanding this process at such high temperatures has potential ramifications for our understanding of material science, forensic biology and volcanology.

But for now, we have an explanation for the Roman whose brain turned to glass. It was highly unlikely, it required a very specific sequence of events, but it seems that we finally understand how such a thing is even possible.

Header Image: The formation of glass inside this Roman’s brain could only come from a very specific sequence of events, but this new study has confirmed that it is, at least, possible. Source: UnexpectedToy / Public Domain.

You may also like

Stolen Hercules Fresco Finds Its Home After Decades in U.S. Collection

Massive Roman Cremation Cemetery Reveals Burial Rituals in Southern France

When Crocodiles Massacred Japanese Soldiers During WWII

Archaeological Evidence Confirms Survivors Returned to Devastated Pompeii After 79 AD Eruption

Humanity’s Timeless Search for Alien Life

Jurassic World Meets the Unknown: Dinosaurs & Mystery Beasts of the Congo Basin

Allthathistory
Written by Allthathistory

Tags: eruption, Herculaneum, Italy, Pompeii, Roman, Vesuvius, volcano

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

  • Ancient Rock Carvings Uncovered in Ecuador Point to Shared Amazonian Cultural Traditions
    Archaeologists have identified a panel containing approximately 30 ancient rock carvings in Santiago de Méndez canton, Morona Santiago province, marking
  • Stolen Hercules Fresco Finds Its Home After Decades in U.S. Collection
    Archaeologists at Pompeii have identified the original location of a looted fresco fragment depicting the infant Hercules strangling serpents, solving
  • Maya Medical Systems Used Living Organisms as Precision Surgical Tools
    Maya medical systems deployed living organisms as precision surgical tools centuries before germ theory existed. Recent archaeological evidence shows these
  • Ancient Rock Art in Texas-Mexico Borderlands Endured 4,000 Years
    Hunter-gatherers in what is now southwestern Texas and northern Mexico created rock art for more than 4,000 years, maintaining consistent
  • The Thermal Engineering Behind Tiwanaku’s Agricultural Success
    At nearly 3,850 meters above sea level, frost arrives almost nightly on Bolivia’s Altiplano. Modern visitors struggle to breathe. Yet
The Gnostic Gospels
Encounters at the Heart of the World: A History of the Mandan People
Substack Articles

Latest from AllThatHistory Weekly

What Sank to the Bottom of a Swiss Lake 2,000 Years Ago

What Sank to the Bottom of a Swiss Lake 2,000 Years Ago

In November 2024, the Cantonal Office of Archaeology of Neuchatel was conducting routine aerial monitoring of the lakebed when a photograph revealed something that did not belong there.

Read More →
13,000 Years Ago, Someone Painted a Bison in the Dark. We Just Found Out When.

13,000 Years Ago, Someone Painted a Bison in the Dark. We Just Found Out When.

The Font-de-Gaume cave sits in a limestone hillside near the town of Les Eyzies in the Dordogne region of southwestern France.

Read More →
The War Horn That Made Roman Soldiers Flinch

The War Horn That Made Roman Soldiers Flinch

In the summer of 2025, during a routine archaeological excavation ahead of a housing development in West Norfolk, England, a construction site turned up something unexpected.

Read More →
Britain Wasn’t Always an Island: The Drowned World Beneath the North Sea

Britain Wasn’t Always an Island: The Drowned World Beneath the North Sea

The North Sea was not always there. Before the water arrived, before the English Channel cut Britain off from continental Europe, there was land. Dry, forested, inhabited land.

Read More →
Iran-War: Near Middle East Burning – Ancient History Repeating?

Iran-War: Near Middle East Burning – Ancient History Repeating?

Watching the Iran-war in the Near Middle East region, our news screens project scene after scene of ominous dark smoke billowing from yet another target hit by an airstrike. The first week of April 2026 heralded the announcement that airstrikes on Isfahan in Iran and southern Lebanon has increased.

Read More →
When Spices Were Worth More Than Gold

When Spices Were Worth More Than Gold

In 410 CE, when the Visigoths besieged Rome, they demanded ransom: gold, silver, silk, and 3,000 pounds of pepper.

Read More →
❮
❯

Subscribe to receive our newest archaeology articles, long-form investigations, and historical insights directly in your inbox.

© Copyright AllThatHistory - 2025