Flying Saucer flint?

[Tam]

Here is one thought . I find so many iron ore pieces that are perfect cylinders . Might have been under water and coral grew on it millions of years ago .
Don't know if your area is that zone .
it’s an interesting site to literally see the earths crust cooled and if it were under water that could have happened .

[Glacial Pebble]

Agree with Kim, nice find!

[Glacial Pebble]

That’s a dandy specimen Kim!

[Mattern]

I thought you might think so, if you saw a more defined example. They are very similar in contexed. Kim

[Charles Jones]

You may be right! There is some definition that looks like coral if you look close enough.

[Mattern]

Hay again Charles. I think what you have is a fossilized Coral. Some like yours aren't as defined. The dimple is the nucleus where it started to grow from This one is Limestone and Calcite. Kim

[Charles Jones]

Other than the color, looks similar.

[Cecilia]

Look at this rock. One side rounded/domed, other side flat with a “button” in its middle. It’s a concretion that’s been broken open ! Pretty neat.... The button is probably the lil’ organic whatever around which the concretion formed.

[Charles Jones]

We don’t have anything like this within 50 miles of where I found this. I’m thinking it had to be brought here by someone a few hundred years ago.

[clovisoid]

Cool find, some of the limestone formations in the Midwest/Mississippi river valley have lots of types of chert nodules. I've seen some flat "pancake" nodules in some areas.

[flintguy]

Ok, I figured you'd know, plus having it in hand of course. Hopefully someone has an idea.

[Charles Jones]

I’m 99% sure it is a natural formation. Found miles from any place that might have used concrete like that. Can also see it is made up of many layers.

[Cecilia]

Sometimes concretions form in this shape. Only way to know is to bust open, but DONT!

[flintguy]

That is a head scratcher. I haven't seen anything like it. Just curious but are you sure it's not some kind of industrial waste? There are some concretes that are fine grain and even made from limestone dust that can appear like a natural stone. Not saying you don't know your artifacts because I know you do, it's just that looks more like a poured, hardened material judging just from the two pics. I'll be following this post to see what others might know about it.

[SGT.Digger]

Interesting