Why is this red

[aps13034]

I found this fossil in Ossineke Michigan in a field and I’m curious to know what it is and why it is red. It seems kind of like incomplete horn coral but the red color and texture of the red part is strange. Most of the fossils in our area are Devonian.

[Tidgy's Dad]

Yes, a solitary rugose coral, maybe a button coral? 

The red is a mineral, probably containing iron. 

[Pippa]

42 minutes ago, Tidgy's Dad said:

Yes, a solitary rugose coral, maybe a button coral? 

The red is a mineral, probably containing iron. 

Agreed. Many Great Lakes fossils and rocks are iron stained. It's what gives the famous Lake Superior agates their red color as well.