How do the Minerals in the Soil, and the Environmental Conditions; Create the Colors we see in Fossils?

[Rock Hound]

Will someone who has knowledge about this subject, please explain how and why we have so many interesting color variations in the world of fossils?  Shark Teeth, Ammonites, Petrified Wood, etc.  There are so many different color variations.  And I like it!!!

[FranzBernhard]

The most important minerals that fossils are composed of are calcium carbonate, silica minerals and apatite. All of these are white to colorless in the pure state.

 

Important colorizing agents mostly in the form of very minute admixtures in pores, grain boundaries etc. of fossils and rocks are:

- Iron compounds, resp. iron hydroxides (goethite and others, generally known as "limonite", brown) and iron oxide (hematite, red). But also iron silicates, which can be green (glauconite, chlorite)

- "Carbon" in the form of finely divided coaly particles (black).

 

More rare are:

- Manganese oxides (rare, black)

- Copper and chromium compounds (very rare, both green).

 

Depending on the concentration of the colorizing compound, you can get also yellow with goethite or pink with hematite.

Some others sure can give you more detailed and in-depth answers.

 

Franz Bernhard

[Ludwigia]

Vivianite could also be mentioned. An iron phosphate which colors things many shades of blue to blue-green.

[Tidgy's Dad]

Then again we can force dye agates and other minerals and paint the fossils, like we sometimes do in Morocco. 

Lovely. 

[Denis Arcand]

5 hours ago, Rock Hound said:

Will someone who has knowledge about this subject, please explain how and why we have so many interesting color variations in the world of fossils?  Shark Teeth, Ammonites, Petrified Wood, etc.  There are so many different color variations.  And I like it!!!

 

If you like colorful fossils, you might like the following

 

[Troodon]

From the Museum of Nature:

https://nature.ca/en/what-colour-are-fossils-where-science-and-artistry-merge/

 

 

[doushantuo]

good concise summary,Franz

[Rock Hound]

8 hours ago, Troodon said:

From the Museum of Nature:

https://nature.ca/en/what-colour-are-fossils-where-science-and-artistry-merge/

 

 

A good reply, to this topic.  Thanks.

[Rock Hound]

20 hours ago, Denis Arcand said:

 

If you like colorful fossils, you might like the following

 

Thanks.  I actually participated in that thread.

[Rock Hound]

On 5/12/2023 at 12:26 PM, FranzBernhard said:

The most important minerals that fossils are composed of are calcium carbonate, silica minerals and apatite. All of these are white to colorless in the pure state.

 

Important colorizing agents mostly in the form of very minute admixtures in pores, grain boundaries etc. of fossils and rocks are:

- Iron compounds, resp. iron hydroxides (goethite and others, generally known as "limonite", brown) and iron oxide (hematite, red). But also iron silicates, which can be green (glauconite, chlorite)

- "Carbon" in the form of finely divided coaly particles (black).

 

More rare are:

- Manganese oxides (rare, black)

- Copper and chromium compounds (very rare, both green).

 

Depending on the concentration of the colorizing compound, you can get also yellow with goethite or pink with hematite.

Some others sure can give you more detailed and in-depth answers.

 

Franz Bernhard

Thank you, for your response.

[Rock Hound]

On 5/12/2023 at 12:49 PM, Ludwigia said:

Vivianite could also be mentioned. An iron phosphate which colors things many shades of blue to blue-green.

Vivianite, is such an interesting name.  As though it was named after someone, named Vivian?

[Ludwigia]

3 hours ago, Rock Hound said:

Vivianite, is such an interesting name.  As though it was named after someone, named Vivian?

Yes, it was named after a man called Vivian, but no one knows if it was John Vivian the politician or Jeffrey Vivian the mineralogist. They forgot to ask Abraham Werner, the man who named it, and he's dead now.