How to get Pearls from Fossil Oysters?? Prep or Matrix removal

[HFVC Fossils]

Can I get some help on How to Find or extract Fossil Pearls in complete Exogyra Ponderosa Oyster shells??

 

I put this up as a challenge on my YouTube channel for the Fossil Forum, hopefully you guys find this fun and hopefully it brings in some more members to the Forum here!!

 

I'm also including some photos to help see the Test Subjects involved!

 

my main question is: How do I remove the grey 'clay' matrix (probably Ozan Formation, or a lower level) without doing damage to the Shells or any possible Oysters hidden within!!

 

I've never really prepped a fossil before.  Just washed them. And I don't have any prep tools, but I have lots of random stuff I might be able to use to improvise with!!!

 

Thanks so much!!!

Let's find some PEARLS!!!

[DPS Ammonite]

Nice Exogyra, did you find them in the North Sulphur River?

 

Fossil peals are rare. I have never heard of anyone finding one inside of an Exogyra. In modern oysters only 1 in 10,000 has a natural pearl. Cleaning the hardened sediment is tough and you are not likely to find any pearls. If pearls are common, someone might have found them in the sediment in the North Sulphur River. Anyone find any?

 

By trying to clean the insides, you might damage the real treasure, the whole shell. I've tried to clean several of them. I start by soaking them in water or hydrogen peroxide. I scrape off what I can with a hardwood stick or a metal probe with a rounded tip. You also can try to selectively dissolve the cement of the filling (interior mold) with 10% HCl acid by placing the acid with a dropper onto the mold. Realize that the acid will also dissolve the shell. After many days of soaking, dissolving and scraping I cleaned up the interior of one shell. Several of the whole shells cracked or fell apart when they were soaked. In other words, it is not worth the effort to clean them only to look for pearls. It is worth the effort to clean ones with soft interior molds to better display the shells.

 

Look for pearls in the Kamp Ranch Formation north and west of Dallas where many ones have been found. Good luck.

 

See these FF posts: http://www.thefossilforum.com/index.php?/search/

 

Here's an abstract from Dallas Paleontology member, Virginia Friedman, about Kamp Ranch pearls:

https://gsa.confex.com/gsa/2004AM/finalprogram/abstract_75787.htm

 

[HFVC Fossils]

Yes, the NS River! 

Hmmmm, I will not be discouraged!!   If they haven't been discovered there before, then it would be quite a discovery if I could find one inside!??

 

i need to see if I still have any dental picks!  And then I'll start with the one who's bottom shell has already separated. 

 

I'm hoping for more suggestions, cautions and all the info ya'll have to offer.  I want to do this right!

 

Thanks!

[DPS Ammonite]

Take your shells into a Dallas Paleontology Society meeting and ask how members would clean/prep them since many members have probably done the same.

 

Also, when looking for fossil pearls, you need to look in rocks where the original aragonitic mother of pearl is preserved in the shells. Aragonite is unstable and dissolves before the calcite shells. That calcite Exogyra shells are preserved but not their mother of pearl lining probably because the Ozan Formation is porous to the flow of water which dissolves the aragonitic mother of pearl. The nearby dark shales in the North Sulphur River might be a better place to look for pearls because they contain thin fragile Inoceramus shells with mother of pearl and the shale is more impervious to water flow.

 

I suspect that pearls occur in the Kamp Ranch Formation because the limestone is tightly cemented blocking water flow and the surrounding layers of shale are relatively impervious to water flow.

[HFVC Fossils]

49 minutes ago, DPS Ammonite said:

Take your shells into a Dallas Paleontology Society meeting and ask how members would clean/prep them since many members have probably done the same.

 

Also, when looking for fossil pearls, you need to look in rocks where the original aragonitic mother of pearl is preserved in the shells. Aragonite is unstable and dissolves before the calcite shells. 

Unfortunately we live nearly 3 hours outside of Dallas, and we are moving soon.  So I don't think a meeting appearance is likely. 

 

Good point on the Mother of Pearl absence.  Yes, these oyster shells rarely if ever have much/any mother of pearl showing.... So probably little hope for pearls....