Heat from the eruption in A.D. 79 was so intense that it vitrified the brain tissue of one unfortunate Herculaneum resident, a new study confirms.

A unique dark-colored organic glass, found inside the skull of an individual who died in Herculaneum during the 79 CE Mount Vesuvius eruption, likely formed when they were killed by a very hot but short-lived ash cloud.

It was a surprising discovery when scientists examining the remains of a man who died in bed in the ancient city of Herculaneum after Italy's Mount Vesuvius erupted in 79 AD found dark fragments resembling obsidian inside his skull.