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How do bones turn into stone?

Fossils form when mineral-rich water fills the tiny holes in buried bones, and footprints and even fossil poop can turn to stone too.

On air: Dr. Nina Byte and Chip Darnell on BBN After Hours
Published 2:52 AM ET, Monday, October 26, 2026

At a glance

First reported by Wikipedia: “How do bones turn into stone?”
Covered on BBN on Monday, October 26, 2026, at 2:52 AM ET on BBN After Hours, by Dr. Nina Byte and Chip Darnell.

The reporting behind this segment. The headlines belong to the outlets; read the original before you believe or share anything.

Dr. Nina Byte · Tech & Science CorrespondentChip asked me how bones turn into stone, and now explaining rocks to a grown man in a tiny chair is my entire career.
Dr. Nina Byte · Tech & Science CorrespondentStep one. A long time ago, an animal got buried in mud or sand, and the burying kept its bones safe.
Chip Darnell · U.S. News AnchorSo the mud is like a pantry. You put the bones away for later.
Dr. Nina Byte · Tech & Science CorrespondentStep two. Over a very long time, water full of minerals soaked into those bones.
Chip Darnell · U.S. News AnchorMarinating. So the bones sit in the ground like a rack of ribs. How long is the cook time?
Dr. Nina Byte · Tech & Science CorrespondentPer Wikipedia, it's called permineralization, and it's minerals filling the spaces in buried bones. Step three: the minerals slowly fill the tiny holes and harden.
Chip Darnell · U.S. News AnchorSo it's sauce.
Dr. Nina Byte · Tech & Science CorrespondentIt is not sauce. Step four: the bone becomes a rock copy of itself. That's a fossil.
Chip Darnell · U.S. News AnchorFossil poop. Love it. Love all of it. Can I hold some?
Dr. Nina Byte · Tech & Science CorrespondentThe word is coprolite, and yes. There's one on my desk, and you're not allowed to name it.