How do you know if it's a fossil?

[Andy B]

My second question tonight. I found a few shark tooth shapes that seemed interesting enough to not toss back in the Big Brook this weekend. I was hoping for some advice.

 

One seems to me to be a fractured tooth with mostly the root remaining (the larger black one). It feels dense and hard like a stone. I couldn't tell at the site with my bad eyes but there are some groves in part of the "tooth" that help make it look like something of the tooth variety. It certainly appears to be something significant, if only a piece of it. The smallest black item is hard like a rock as well yet seems like it would have been a tooth. There are no clear signs though. Do some fossils lose their definition like this? And lastly, I found something that looks like the shape of a tooth but it may be embedded in some other substrate. Can I scratch away at it with a pick, or tap at it with a small rock hammer or the like to see if anything comes off?

 

Thanks for your patience.

 

Andy

 

[Fossildude19]

Good call on keeping these.  

They look like fragments of the fish Enchodus petrosus. 

The second one is iffy, but the two on either side look like it to me. 

 

When in doubt, don't throw it out.  

Lets see what some of the others have to say. 

 

[oldtimer]

I agree on the outer two.  The center one I am not so sure about.

Yes you can scratch and use a pick tool, not a hammer to help reveal what may be under the matrix.

You can also use an electric engraver if you have one to aid in matrix removal.

Search fossil prep to get some ideas on how this is accomplished.

Soaking in vinegar may help loosen and soften up the matrix too.

[Andy B]

Thanks guys. I am going to soak the middle one. We'll see how it goes!

[RJB]

  I wish you the best of luck Andy.  Looks like you have something there.  Not my kind of 'stuff', but you deffenetly have some fossils there.

 

RB

[goatinformationist]

If the center item is limestone try vinegar.  It won't hurt the fossils but will melt the matrix.

[erose]

15 hours ago, goatinformationist said:

If the center item is limestone try vinegar.  It won't hurt the fossils but will melt the matrix.

 AAAAAAHHHHH! No, no, no! Pardon me being so adamant but that is a common misnomer. VERY often fossils in limestone are also preserved as calcium carbonate. Vinegar and other acids will attack them as well. You can certainly give it a try but dilute the vinegar in water 1:5, respectively, and soak for maybe 15-20 minutes keeping a close eye on it. Then scrub and rinse, rinse rinse...

 

[jpc]

14 minutes ago, erose said:

 AAAAAAHHHHH! No, no, no! Pardon me being so adamant but that is a common misnomer. VERY often fossils in limestone are also preserved as calcium carbonate. Vinegar and other acids will attack them as well. You can certainly give it a try but dilute the vinegar in water 1:5, respectively, and soak for maybe 15-20 minutes keeping a close eye on it. Then scrub and rinse, rinse rinse...

 

I agree.  To do acid prep the fossils need to be calcite free.  The best way to find out is to just try it.  If the fossil is calcitic, you will ruin it and not do it again...  : )

 

 

[goatinformationist]

More likely aragonite which is more resistant to a mild acetic acid.  Living in Florida so long along the limestone/phosphate pits I used vinegar regularly with fabulous results.  So use full vinegar on a very small sample of your stone before committing to a full bath.  Moderate as useful.

[goatinformationist]

PS...

Cleaning Fossils With Vinegar - Questions & Answers - The Fossil Forum

www.thefossilforum.com › Fossil Discussion › Questions & Answers

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