Pyrite and Hematite Fossils

[JulianoLPD]

Hi there, guys. 
I've been learning a lot from you in the past few days and now I got another doubt.
Found the following fossil is the auction website and it kept me thinking. Is this fossilized that way?
I mean, I do believe they are real fossils, but were they fossilized by pyrite or hematite or were they treated somehow and covered with the mentioned metals?
They do look pretty in my opinion, but if they are a result of a natural process (what I don't believe) that is even more amazing!!
Just wanna hear your thoughts.

Thanks in advance,
Juliano

[Kane]

I commonly find fully pyritized ammonoids and nautiloids at one of my collecting locations. Pyritization favours anoxic deposition / rapid burial conditions contingent upon available sulfides, etc., to permit the complete mineralization replacement of hard shell material. These seem authentic to me. 

 

The one exception to be on the look-out for is when a preparator applies a brass wheel brush on a specimen to give it a metallic sheen, or when some use paints. I find that to be more the case with some trilobites, but haven't seen that process performed on ammonites or ammonoids. 

[Tidgy's Dad]

Yes, these are all real and natural and very pretty.

Just like me.

[Innocentx]

1 hour ago, Tidgy's Dad said:

and very pretty.

Just like me.

Amazing what the plastic surgeon can do just by pushing a few buttons.

[daves64]

4 hours ago, Tidgy's Dad said:

Yes, these are all real and natural and very pretty.

Just like me.

It's really amazing what can be done with makeup and a putty knife. 

[Tidgy's Dad]

2 minutes ago, daves64 said:

It's really amazing what can be done with makeup and a putty knife. 

And you're accusing wifey? 

[daves64]

23 minutes ago, Tidgy's Dad said:

And you're accusing wifey? 

Only if she's using it on you. She doesn't need it. 

[Tidgy's Dad]

1 minute ago, daves64 said:

Only if she's using it on you. She doesn't need it. 

Neither do i! 

Skin as smooth as a baby's bottom.

Apart from the spots, wrinkles and scars, of course. 

[Mediospirifer]

Yes, I agree with the above comments, these are natural.

 

A few years ago, we had a thread about mineralization types: LINK. Check it out! There's an impressive variety of possible minerals that a fossil can incorporate, and some of them are spectacular.

 

[Ludwigia]

7 hours ago, JulianoLPD said:

Hi there, guys. 
I've been learning a lot from you in the past few days and now I got another doubt.
Found the following fossil is the auction website and it kept me thinking. Is this fossilized that way?
I mean, I do believe they are real fossils, but were they fossilized by pyrite or hematite or were they treated somehow and covered with the mentioned metals?
They do look pretty in my opinion, but if they are a result of a natural process (what I don't believe) that is even more amazing!!
Just wanna hear your thoughts.

Thanks in advance,
Juliano

Nature is amazing. Yes, these are all the result of a natural process. The process which Kane describes above is called permineralizaton.

[JulianoLPD]

Wow! Thank you guys!
That's really amazing indeed. Had no ideia!
I saw somewhere that these metalic fossils should be treated with some kind of protective layer in order to prevent rust. Is that correct?

3 hours ago, Mediospirifer said:

Yes, I agree with the above comments, these are natural.

 

A few years ago, we had a thread about mineralization types: LINK. Check it out! There's an impressive variety of possible minerals that a fossil can incorporate, and some of them are spectacular.

 

I'll take a look at that right now! Thank you!