Septarian nodule

okiedokie59 · Jun 19, 2025

Picked this up at a Texas yard sale back in the 80s and now looking at parting ways. I do not know what state it was uncovered in. It is heavy and makes a wonderful door stop. Since I've owned it it has seen Texas, Florida, Missouri and Oklahoma. LOL, So it's not only ancient but also well traveled with high mileage. Pictures are screen shotted from a previous 2018 posting on a local forum.
Question, can one of y'all let me know the best place to unload this for some jingle. Please and thank you. Yes, my 1st post and quite likely one of only a few.

robertk · Jun 19, 2025

That kinda resembles a fossilized turtle. If so, it's not a septarian nodule. On the other hand, if it's a septarian nodule, it's not a fossil at all. Either way, if you're looking to sell it here, you need to become a charter member. If you just want to sell it generally, a local rock shop or collector event would be a good place. Make sure you know what it is first -- turtle vs nodule makes a difference.

Red-Coat · Jun 19, 2025

Welcome to Tnet.

Definitely septarian (concretion rather than nodule, if we're going to be properly geologic.) It's possible for small decomposing fossil remnants (often bivalves) to trigger formation or act as a nucleus, but it's essentially non-fossil. Definitely not a turtle.

Internet sellers seem to be asking between about $100-150 for large ones but, personally, I wouldn't pay that kind of money.

okiedokie59 · Jun 19, 2025

Red-Coat said:
Welcome to Tnet.

Definitely septarian (concretion rather than nodule, if we're going to be properly geologic.) It's possible for small decomposing fossil remnants (often bivalves) to trigger formation or act as a nucleus, but it's essentially non-fossil. Definitely not a turtle.

Internet sellers seem to be asking between about $100-150 for large ones but, personally, I wouldn't pay that kind of money.

You are correct, my copy and paste grabbed nodule. I paid $50 at the yard sale. I see one on ebay for $2500. Not looking for that but a profit would be nice. I've lugged it around the country over the last 40 years. Thank you for the reply. Tim.