A Prep I'm Actually Proud Of

[Calli99]

Hi everyone

 

These two pieces were collected by my boyfriends father and his family about 60 years ago on the Jurassic coast of Charmouth/Lyme Regis. A little while ago he brought them out to show me and said I could keep the ones I liked. I chose these two, but not to keep. My idea was to prep them, reveal the fossils inside and give them to him at Christmas.

 

I used a Dremel with specialised tips and a sewing needle in a pin vice under a microscope. Overall I'm quite happy with how they turned out, not perfect, but I can see my own improvement. 

 

The larger single ammonite (Promicroceras sp. I think) had significant pyrite rot on the matrix on the reverse side. I removed it with the Dremel and will coat the ammonite and the reverse side with Paraloid. As you can see, the matrix split beside the ammonite whilst I was Dremelling. It would be great to hear opinions on whether you think the piece looks better with the matrix glued back on, or left alone?

 

I would love to hear any advice and critical feedback. 

 

Before:

 

The reverse side

 

After an hour or so on the Dremel:

 

The reverse side, after removing the pyrite rot:

 

All finished after a bit more Dremel work and about 2 hours with a needle (no Paraloid yet though):

With the excess matrix:

 

Without the excess matrix:

 

The second piece, before:

 

After an hour or two with a needle:

 

After about 40 mins with the Dremel:

 

All finished after a few more hours with a needle and some Paraloid to glue back the broken pieces and stabilise:

[Kane]

Well done!

Unfortunately, I am low on critical feedback at the moment, and high on praise.  

I especially like that first piece and how it now has a natural presentation pedestal (so my vote is to leave the excess matrix off). You also managed to clean out all those inner whorls nicely, which must have taken a bit of time. 

[Ludwigia]

I'd like to second Kane's comments and add my praise for a job well done.

[Tidgy's Dad]

Thirded! 

[Fossildude19]

Great job!

[Mainefossils]

Amazing prep! Fifthed - man, this is terrible grammar.  

[Calli99]

Wow, thank you all for your incredibly kind words! It means all the more coming from members I regard so highly

[Malcolmt]

Very nicely done. Keep it up and you'll be putting us all to shame

 

[Ptychodus04]

Great job @Calli99 I agree with the others, I would leave the broken matrix off the 1st piece. I suspect that these were kept in a box previously and also suspect that they will be out for viewing now. That makes a world of difference on the advancement of pyrite decay. Closed up in boxes tends to accelerate the process.

 

Using Paraloid to help seal a specimen to slow/stop pyrite decay is a rather invoked process, more so than simply coating the specimen. A coating without any treatment of the pyrite simply puts lipstick on a pig. The decay continues under the surface and your specimen crumbles.

 

I would suggest NOT using Paraloid and watching the specimen over the next few years to see what the pyrite does. Address it then if you have to.

 

I’m going to be a bit more presumptuous than @Kane and jump right into critical feedback.  There’s only one piece of advice I would offer. Spend some time removing your tool marks from the matrix. You’re prep and presentation looks so much better when this is done. The specimen is the star and the viewer’s eye tends to be drawn to the tooling marks.

 

Great prep work and what a wonderful Christmas present! Very thoughtful.

[minnbuckeye]

Excellent preparation on your part with simple tools we all should have access to!!!! I am going against everyone's suggestions on the matrix question assuming it is going to be exhibited verses filed in a drawer. Without the more matrix, the ammonite looks like it is sitting unnaturally on a pedestal.  To improve the look, I would reattach roughly HALF of the matrix, giving you a more substantial and naturally looking base for display purposes. The larger base would also provide more stability.

Edited December 11, 2021 by minnbuckeye

[Calli99]

36 minutes ago, Ptychodus04 said:

Great job @Calli99 I agree with the others, I would leave the broken matrix off the 1st piece. I suspect that these were kept in a box previously and also suspect that they will be out for viewing now. That makes a world of difference on the advancement of pyrite decay. Closed up in boxes tends to accelerate the process.

 

Using Paraloid to help seal a specimen to slow/stop pyrite decay is a rather invoked process, more so than simply coating the specimen. A coating without any treatment of the pyrite simply puts lipstick on a pig. The decay continues under the surface and your specimen crumbles.

 

I would suggest NOT using Paraloid and watching the specimen over the next few years to see what the pyrite does. Address it then if you have to.

 

I’m going to be a bit more presumptuous than @Kane and jump right into critical feedback.  There’s only one piece of advice I would offer. Spend some time removing your tool marks from the matrix. You’re prep and presentation looks so much better when this is done. The specimen is the star and the viewer’s eye tends to be drawn to the tooling marks.

 

Great prep work and what a wonderful Christmas present! Very thoughtful.

 

Thank you @Ptychodus04, you're right, they were kept in a tin with dozens of other fossils which were all at quite advanced stages of pyrite rot. I certainly hope they will now be on display! I will follow your advice re the Paraloid, and try to make sure it doesn't go on display in the bathroom with all the other shells and beach memorabilia.

 

I appreciate your feedback! I think you're right, particularly on the multi ammonite specimen which I will go back over. It is tricky to get it perfectly smooth with the Dremel but I do prefer a more natural look, so won't bother to go over the rougher rock, just the tool marks like you mentioned.

 

Thank you again for your lovely comments and advice!

[Calli99]

13 minutes ago, minnbuckeye said:

Excellent preparation on your part with simple tools we all should have access to!!!! I am going against everyone's suggestions on the matrix question assuming it is going to be exhibited verses filed in a drawer. Without the matrix, the ammonite looks like it is sitting unnaturally on a pedestal.  To improve the look, I would reattach roughly HALF of the matrix, giving you a more substantial and naturally looking base for display purposes.

 

Thank you so much! The more I look at it the more I find myself leaning towards reattaching the broken matrix, despite most people saying otherwise! I agree that it looks more unnatural without the extra matrix and I do prefer a more natural, contextual look. But everyone prefers it without, I just can't decide!

 

By reattaching half, do you mean essentially cutting the matrix in half laterally, almost so it lines up with the end of the body chamber?

[hadrosauridae]

Wonderful prep work!  I agree with the previous comments by ptychodus about the pyrite decay.  I have been reading about it a lot lately, and it seems there is nothing that can truly stop it.  Its a self-sustaining chain reaction.  There are chemical treatments that can treat it, but I believe those only extend the life.  

[Ptychodus04]

1 hour ago, Calli99 said:

 

I appreciate your feedback! I think you're right, particularly on the multi ammonite specimen which I will go back over. It is tricky to get it perfectly smooth with the Dremel but I do prefer a more natural look, so won't bother to go over the rougher rock, just the tool marks like you mentioned.

Good plan. Remove what you can and leave the untouched matrix alone. This makes for a much nicer looking specimen.

 

 

1 hour ago, Calli99 said:

I agree that it looks more unnatural without the extra matrix and I do prefer a more natural, contextual look. But everyone prefers it without, I just can't decide.

I prefer a natural look as well. The reason I like the broken bit off is due to the obvious crack that you will have once you glue it back on. In this scenario, I lean towards the smaller matrix for that reason only.

 

 

57 minutes ago, hadrosauridae said:

I have been reading about it a lot lately, and it seems there is nothing that can truly stop it.  Its a self-sustaining chain reaction.  There are chemical treatments that can treat it, but I believe those only extend the life.  

You’re right, there’s no real way to stop it. Being in a tin around other pyrite decay speeds the process where being in the open in a relatively low humidity environment slows the process. I have specimens which exhibited pyrite decay that I treated with Iron Out and stabilized with Vinac (quite a labor intensive process) that are stored in closed trays that are not continuing to progress. Most of these have been sitting for around 15 years.

 

Since the decay was in the matrix rather than the specimen itself, there’s much less concern. The ammonite is calcified rather than pyritized, so the concern for the specimen is even further reduced.

[minnbuckeye]

Here was my thoughts were it mine. Cut along the black line and also chip somewhere between the blue and red line. The nice thing is no matter what you decide, your fossil is amazing!!

 

  

Edited December 11, 2021 by minnbuckeye

[fossilhunter21]

Very nice job! 

 

Looking foward to seeing more of your work. 

 

-@fossilhunter21

Edited December 12, 2021 by fossilhunter21

[RJB]

Ninethed.  Not sure how to even spell that?  

 

RB

[pachy-pleuro-whatnot-odon]

Wow! Great job on preparing those ammonites! I've got some of those lying around myself that I'd love to get my hands on once I've actually got the proper tools for it (which means I'd first need to get a more decent home for ourselves rather than living in a tiny apartment in a building with others - hopefully just a few more years!). The main point being, they look pretty good. I too especially like the pedestalled look of the first specimen a lot 

 

I agree with @Ptychodus04 in that removing tool marks really only benefits a fossil by directing attention away from the marks to the fossil itself.

 

And next I'm going to shamelessly promote my own thread down below in reference to treatment of pyrite decay. For I'm in the process of dealing with a case myself and have been doing quite a bit of research on the topic lately, as well as having had discussions with professionals in the field. @Ptychodus04, again, has made some very good comments already on the fact that your specimens are calcitic and you, therefore, don't need to fear them becoming affected by the decay. In addition, I wonder whether there's any pyrite in your matrix at all, as the affected spots look like staining rather than anything else.

 

Thing with pyrite is that it comes in two crystalline forms: stable and unstable. The stable variant is not of concern, as it will remain stable through time. The unstable variant, however, will take various amounts of time to decay. It does so under fluctuations in moisture and, mostly (as I've come to understand), oxygen. Sealing a specimen is rarely a solution, as 1) it's hard to get the seal airtight and 2) it doesn't treat any rot already present in the specimen itself, thereby leading the specimen to fall apart from within over time (though how much time is hard to say). One way to reduce the risks of the decay, as comes recommended by professionals in the field, is therefore to reduce the matrix surrounding a pyritiferous specimen (another reason to keep the pedestalled specimen the way it is and not restore the removed matrix), reducing exposure. One would then treat such a specimen using ethanolamine thioglycollate (known commercially as pyrite stopper or pyrite stabilizer) to make sure that any decay products have been removed, and lastly seal the specimen using Paraloid B-67. The latter differs from the more commonly used B-72 variant by discolouring and loosing effectiveness over time, but in its place it offers much better hydrophobic properties, thus better protecting your specimen against the moisture that could trigger further pyritic decay.

 

The most worrisome element of the pyritic decay process, by the way, is the production of sulphuric acid, which is what may help decay progress inside a specimen without any obvious traces on the outside and which, in gaseous form, may trigger or accelerate the potential for or existing pyrite decay in other, nearby specimens. This is where the idea of pyrite decay spreading comes from. However, if the pyrite in this nearby pyritiferous specimen is of the stable kind, that specimen will remain unaffected. In your case, I get the impression from the photographs that your specimen itself hasn't actually been affected by pyrite rot, but has instead rather been exposed to precipitation of sulphuric acid and decay products of other fossils in the same tin, waste products that have since crystallized onto your matrix. Thus, removing the affected matrix should be a good step in ensuring the rot doesn't spread. It may, however, be wise to rinse the specimen in anhydrous alcohol (though I've heard running demineralised water should also work), just to make sure that all the sulphuric acid has washed out...

 

 

[Pagurus]

You certainly should be proud of this great-looking prep! Well done.

[Neanderthal Shaman]

Very nice! I just got a Dremel with some specialty tips a couple of weeks ago. It works well, did a nice shrimp claw on my first try!  Been striking out on all the concretions since then, but using the Dremel is a blast, even when you're working on a dud for 1 1/2 hours.