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MedicineHat

I hammered this free from a chunk of ironstone. Ironstone matrix. I thought it was completely round like a marble nut the more I inspected I see some traits that this is a designed specimen with a symmetrical pattern and some unique patterns.

Any ideas?

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Fossildude19

This looks like an iron/siderite concretion, to me. :unsure: 

Wait for some more opinions, though. 

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Tidgy's Dad

Yes, a concretion, methinks. 

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MedicineHat

20180326_083217_crop_170x182.jpg

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Malone

It looks somewhat botryoidal beneath the "crust", and the anomaly to the spherical shape is curious. Concretions are a very intriguing form. I am studying them vigorously to try to understand their origins. I believe, from what I have read, some are still a mystery to science. Trying to understand the precursors to the current physical/chemical state will be a main defining factor when visual characteristics are ambiguous. I have found hundreds of concretions and believe the shapes, even when completely mineralized and taken an unoriginal shape, can help with identification. It would be interesting to know what is "inside". I have found pyrite and limonite in the ones in my area, but have read of many different elemental combinations. Until I have access to  costly equipment I will remain ignorant in many respects. I am still trying to understand whether chemicals migrate to or away from an object. If both are true then how to determine which is which. I am sure there are more informed people than me. I will watch this thread and similar ones to learn. Thank you for your post!

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MedicineHat

Thanks everyone for your input. It sounds like it is probably a concretion then. I almost certainly thought it was something else because of the shape, but maybe someone else will have a differential diagnosis.

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Malone
1 hour ago, MedicineHat said:

Thanks everyone for your input. It sounds like it is probably a concretion then. I almost certainly thought it was something else because of the shape, but maybe someone else will have a differential diagnosis.

I would still curious of the origin. A seed or numerous other objects could be the source. If you do end up cutting it open I would certainly be interested in what you find. Even if you don't cut it open and you find out any more about the object I would be interested. Many concretions have organic origins. Anyway have a great day!

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Malone

Here's a pic of some from Pueblo Colorado and one that I opened.

 I don't have a definitive origin for these. 

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IMG_3003.JPG

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Malone

The U.S.G.S. only says there are limonite/ siderite/ goethite/ and pyrite concretions. The only statement of origin is limited to a statement saying fossils are sometimes the nucleus. 

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