To make glass from soft tissue the sequence of events must be exactly right. This is how experts think it went down

A rare organic glass was found inside a skull from Herculaneum’s 79 CE Vesuvius eruption. Researchers determined that a super-heated ash cloud briefly raised the brain’s temperature above 510°C, then cooled rapidly,

The eruption of Mount Vesuvius 2,000 years ago turned a victim’s brain tissue into glass. Scientists say they have figured out how this unusual phenomenon occurred.