Help identify a large round rock

Factual Questions
1

My dad sent me a link to this video. 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.

2

Looks like a 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.

3

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.

4

It just looks like a weathered granite boulder to me. 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

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

5

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:

So, maybe a dolomite concretion?

6

Yep, the globular core or speroidally weathered granite. The split half shows how deep the weathering goes in.

7

Huron Boulder. - yes a concretion from sedimentary material, found in the Huron shale “play” (a lake/sea bed)

Not rare.
They break easily.

See

8

Thanks a bunch! Those rocks in that first photo in your link look exactly like the rock in the video.