NotRocky Posted June 11, 2023 Share Posted June 11, 2023 Can someone please help me identify this! I found this in NJ while on a walk. Link to comment Share on other sites More sharing options...
jasong Posted June 12, 2023 Share Posted June 12, 2023 Iron/ironstone concretion 1 Link to comment Share on other sites More sharing options...
NotRocky Posted June 12, 2023 Author Share Posted June 12, 2023 Can you tell me more about the interior portion of it? Link to comment Share on other sites More sharing options...
Champ Ferguson Posted June 26, 2023 Share Posted June 26, 2023 On 6/12/2023 at 4:48 PM, NotRocky said: Can you tell me more about the interior portion of it? I agree with jasong and am also interested in hearing more about the interior. Link to comment Share on other sites More sharing options...
jasong Posted June 27, 2023 Share Posted June 27, 2023 6 hours ago, Champ Ferguson said: I agree with jasong and am also interested in hearing more about the interior. I'm very unfamiliar with New Jersey geology (or anything East Coast really), but that looks like the type of ironstone concretion you typically find in sandstones to me. This is simplified, but generally the way these sorts of sandstone concretions form is somewhere in a soil/rock pore, a seed crystal precipitates out of iron rich solutions (maybe just rain percolating down and carrying dissolved iron, or a spring, or a whatever else). Usually it's in soils that later turn to rock, and so larger pore spaces are not uncommon, so you can get fist sized or larger concretions. That initial seed can keep growing, or the environment can cause the minerals to change slightly. Later, the older seed crystal can act as a nucleation site for newer mineral saturated waters, these may contain slightly different minerals since the ground above may have changed over time, and you might get a new ring of slightly different ironstone as a result. The interior of this concretion is the earlier stage, and it appears a later stage occured causing the slightly different outer shell material. But that shell may also just be a weathering rind or chemical alteration too, not sure. Sometimes concretions have a "seed" that is organic - like an ammonite or a leaf. And often you can find fossils inside concretions if you crack them open. This concretion pictured is just a mineral concretion though, and might be formed more along the lines of the process that often happens in sandstones called Liesegang Banding. That's about all I can say from a photo. 3 Link to comment Share on other sites More sharing options...
NotRocky Posted June 28, 2023 Author Share Posted June 28, 2023 Wow thank you so much for taking the time to write all of that. It makes a lot of sense now. How are you with stone artifacts? I’ve found a bunch of stuff Link to comment Share on other sites More sharing options...
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