# Fossils Are Not Bones


{{< photocaption src="fossil-bone.jpg" alt="Fossils are not bones" width="80%" >}}Explained in xkcd style with AI{{< /photocaption >}}


Today I learned that the dinosaur "bones" you see in museums aren't actually bones at all. During fossilization, the original organic material slowly gets replaced by minerals like silica or calcite through a process called [permineralization](https://en.wikipedia.org/wiki/Permineralization). 

What remains is essentially a rock that perfectly preserves the shape and anatomy of the original bone.

So a fossil is more like a natural mineral replica than a preserved body part. The original bone is long gone.