Fossil? Vs just a rock!

[Larry c]

I know I know not great pictures and they are in my hand! I will take more pictures with a ruler. This Rock was found in a field at Blake Farm in South Lyon Michigan. It was in a grassy common area sticking out of the ground and looked completely different than all the other sedimentary type rocks given its unusual Sheen and external surface which looked completely different than the interior surface. Wondering if this is a fossil, fossilized egg, fossilized poop, or just an interesting stone! If it would help I can send better pictures. My hand is average in size! My guess is this should be obvious to someone who knows what they are looking at, which obviously excludes me! Please let me know if you need more pictures and I will supply thanks.

[Ludwigia]

This is an interesting stone, not a fossil.

[jpc]

yeah, just a rock.  

 

[Larry c]

Oh well. Thank you both for your expertise!

[Denis Arcand]

It's curious to see a rock with a thin smooth crust ? How does it form ?

[Larry c]

Yes that's what threw me off. To me it look like those bones I see in the museum poking out of rocks in the color and texture but again I don't know what I am looking at. It it's definitely unusual to me and completely different than any other Rock in the entire field. I'm going to post the pictures to a rocks and minerals for them to see if they have any thoughts I will keep you posted thank you for your interest!

[Fossildude19]

Looks like weathered/eroded chert, which can get smooth looking from being polished in a river, stream, or ocean.

[Larry c]

Interesting, thank you for the response. What has me stumped is this exterior layer which in some aspects it appears to be scaling off from the front but from the back large cracked surface The Edge does look indistinct from the inner material so you may very well be right. Thank you. I was really hoping it was a dinosaur egg or bone, but who doesn't?

[Larry c]

Here are some more of the large cracked surface showing the edge

[Mahnmut]

Hi and welcome to the forum!

I am not saying thats exactly what we are seeing here, but here is one of several ways for a rock to form a thin smooth crust:

https://en.wikipedia.org/wiki/Desert_varnish

Best regards,

J

Edited November 9 by Mahnmut
clarification

[Larry c]

Wow, so interesting thank you. I think you've hit the nail on the head. It does seem to be what we are looking at. Thank you for the interest!

[FranzBernhard]

Could also be a partly weathered ironstone (siderite) concretion.

Franz Bernhard