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Michigan Concretion - My Sedimentary Rock

Submit an Entry: My Sedimentary Rock

By Angela Thomas

Michigan Concretion - My Sedimentary Rock

Concretion pieces

Michigan Concretion - My Sedimentary Rock

Concretion reassembled

Where This Rock Is From (place, type of locality, etc.)

I live in michigan, but i believe it was trucked in from somewhere else to shore up the banks of a river.

What This Rock Is

That's just it, I'm pretty sure that it is some sort of geode. It is cylindrical in shape, but the inside is solid. Concentric rings on the inside that end with a round core. Also, this rock was stuck inside a larger rock, so I had to break it free. It did break off a few pieces, but came out of the other stone pretty easily.

What I Like About This Rock

I've never found a rock like this before and would really like to know what it is. I just started collection rocks and this is a special one. I just think that it is a very interesting stone with its rings and round shape. At first I thought that it might be a dinosaur egg, but i don't think that any more.


  • i am very new to rock collecting, so i don't have much to say on this subject.

Andrew Alden, About.com Geology, says:

This is a classic concretion. See more in the Concretion Gallery.
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