# Help identify a large round rock **URL:** \ **Category:** Factual Questions\ **Created:** [March 19, 2014, 8:50pm UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112 "2014-03-19T20:50:26Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Bumbershoot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bumbershoot/32/3428_2.png) [@Bumbershoot](https://boards.straightdope.com/u/Bumbershoot)\ **Post date:** [March 19, 2014, 8:50pm UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112/1 "2014-03-19T20:50:26Z")
My dad sent me a link to [this video](https://www.youtube.com/watch?feature=player_embedded&v=diyIMLO3eDk). Can anyone provide any information about what kind of rock this is, or how it may have formed? The narrator says it was found while putting in a pipeline. Incidentally, my parents are originally from Cadiz (rhymes with Gladys- it is not pronounced ka-DIZ). I assume a friend or relative sent him the link. Any help would be appreciated. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [March 19, 2014, 9:09pm UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112/2 "2014-03-19T21:09:03Z")
Looks like a [Geode](http://en.wikipedia.org/wiki/Geode) to me. Looks like someone cut it to see if it had any valuable crystals in it and left it when they found none. ---
**Author:** ![Bumbershoot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bumbershoot/32/3428_2.png) [@Bumbershoot](https://boards.straightdope.com/u/Bumbershoot)\ **Post date:** [March 19, 2014, 9:22pm UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112/3 "2014-03-19T21:22:14Z")
You’re right, it does look like a geode. I think they could’ve checked the inside without cutting out such a large section, though. Maybe by drilling a hole in it? I’m not entirely convinced it’s a cut, either- looks like it could be a fracture to me. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [March 19, 2014, 10:45pm UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112/4 "2014-03-19T22:45:59Z")
It just looks like a weathered granite boulder to me. [Spheroidal weathering](http://en.wikipedia.org/wiki/Spheroidal_weathering) is very common in granites and a quick google seems to show that big granite boulders brought down from Canada by glaciers are known in Ohio: [When the glaciers melted out of Ohio many large rocks](http://bigwalnuthistory.org/Local_History/boulder/Sunbury-Boulder.htm) It could also be some sort of concretion, which would make more sense with the local limestones and such. A couple of photos showing the actual texture of the thing would have been a lot more useful than a shaky video. ETA: Here’s another big round glacial erratic from Ohio, soon to be a plinth: [Boulder History](http://rosecransheadquarters.org/Statue/Boulder/History.htm) ---
**Author:** ![Bumbershoot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bumbershoot/32/3428_2.png) [@Bumbershoot](https://boards.straightdope.com/u/Bumbershoot)\ **Post date:** [March 19, 2014, 11:23pm UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112/5 "2014-03-19T23:23:22Z")
> [@GreasyJack](#): > > It just looks like a weathered granite boulder to me. [Spheroidal weathering](http://en.wikipedia.org/wiki/Spheroidal_weathering) is very common in granites and a quick google seems to show that big granite boulders brought down from Canada by glaciers are known in Ohio: [When the glaciers melted out of Ohio many large rocks](http://bigwalnuthistory.org/Local_History/boulder/Sunbury-Boulder.htm) > > It could also be some sort of concretion, which would make more sense with the local limestones and such. A couple of photos showing the actual texture of the thing would have been a lot more useful than a shaky video. > > ETA: Here’s another big round glacial erratic from Ohio, soon to be a plinth: [Boulder History](http://rosecransheadquarters.org/Statue/Boulder/History.htm) Thanks for those links; interesting stuff. I went back and read the description below the video (I know, I should have done that in the first place). Here’s what it says: > [@](#): > > The pipeline workers told me that the object was dug out of the ground to the East / Northeast of it’s current location. When it was found it was “whole” and not in it’s current condition. They didn’t know that it was actually cut into pieces when they transported it here. It subsequently “broke apart” when it was moved here. Also, under closer examination the object seems to be comprised of granite that was shaped into this Ellipsoid and then cut into four equal parts along the long axis. (Please understand that when I found this object I only had a cheap tablet to record this video with.) > > _ **EDIT** _ > I have since found a paper from the Ohio Department of Natural Resources … that suggests that these stones are Dolomite Concretions, however rare in this size, are not unheard of. I suppose the only real question that remains (and it’s a big one) is how was it cut this way considering it was dug from the ground in it’s current state. So, maybe a dolomite concretion? ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [March 20, 2014, 1:32am UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112/6 "2014-03-20T01:32:35Z")
Yep, the globular core or speroidally weathered granite. The split half shows how deep the weathering goes in. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [March 20, 2014, 1:51am UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112/7 "2014-03-20T01:51:59Z")
Huron Boulder. - yes a concretion from sedimentary material, found in the Huron shale “play” (a lake/sea bed) Not rare. They break easily. See > **[geof04.pdf](https://www.ohiodnr.com/Portals/10/pdf/GeoFacts/geof04.pdf)** > > 2.76 KB ---
**Author:** ![Bumbershoot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bumbershoot/32/3428_2.png) [@Bumbershoot](https://boards.straightdope.com/u/Bumbershoot)\ **Post date:** [March 20, 2014, 2:21am UTC](https://boards.straightdope.com/t/help-identify-a-large-round-rock/684112/8 "2014-03-20T02:21:30Z")
> [@Isilder](#): > > Huron Boulder. - yes a concretion from sedimentary material, found in the Huron shale “play” (a lake/sea bed) > > Not rare. > They break easily. > > See > > [http://www.ohiodnr.com/Portals/10/pdf/GeoFacts/geof04.pdf](http://www.ohiodnr.com/Portals/10/pdf/GeoFacts/geof04.pdf) Thanks a bunch! Those rocks in that first photo in your link look exactly like the rock in the video.