ArtnSoul

I appreciate all of your comments and input. And yes, the rock has an outer layer of sorts, there are a couple spots where the outer layer is missing. There are cracks all around the whole rock that seem to be that outer layer that is cracked. Two geology professors at a local college said they really didn't know what it is. One of them said it was extremely dense and heavy... my Mom said she thought she said something that sounded like "barium". As a kid I wondered if it was a geode... but they aren't shaped like that. Because of the way it looked, I also wondered if it started out as something more like a liquid or melted form and then hardened. (But how would something be loose inside of it if that was the case?) The shape of it always intrigued me.... But I'm someone who is clueless about rock formation. Merely a guess on my part. (I used to joke that maybe it was a prehistoric cow paddy that petrified) LOL The college said if they got it x-rayed, maybe it would reveal what was inside. I don't think that my parents would be wanting to cut into it.

Forgive my ignorance, what is a concretion?

Thank you for the replies... and no offense taken either way. It is very very heavy for its relative size. We always wondered what was "knocking/rattling" inside when you shake it.

Hi All, My parents have a rock (maybe it is something else?) My Dad found it over 50 years ago in Maryland in the edge of the water of the northeast river in the Chesapeake. They recently took it to a local college and the geology professors didn't know what it was. One of them said she thought it was thousands of years old and that it was formed before the river would have been there.. I'm very interested in finding out what it is, as it has been a mystery all of my life. Also...when you shake it, something rattles inside of it. And it is very heavy for it's size. My Mom used it for a doorstop for many years. That is a quarter in the pic

I'm new here. My Dad found a rock (maybe it is something else?) Over 50 years ago in Maryland, on the edge of the water of the Chesapeake. We're trying to get it identified. They recently took it to a local college and the geology professors didn't know what it was. I will be getting pics to post soon. Thank you for any help that may be provided.