A rock in a rock?

Hello ATS. I thought maybe you could help me out with this. I was at the beach the other day and spotted this strange rock in the waterline. Brought it home of course. At first i thought it was some kinda a metalrod stuck in the rock by some heat proccess, but I ran my metaldetector over it and i got no signal. So no, it is not metallic in nature. It is hard, like rock hard, so maybe it is a rock in a rock?. I dont want to crack it open as it looks soo cool.

Anyone seen this before?



















Thanks in advance!

It looks to me like an igneous rock surrounded by a sedimentary rock. I can't quite tell because you gave us no "hardness' indication, but that's what it looks like. So the had rock was lying in a place where sediment surrounded it and hardened. Likely it was completely surrounded by the sediment. Afterwards, the combined piece was subject to erosion, in this case likely by wave action, hence your very cool rock.

a reply to: Nettlas

If you polish that stone, it might look like an agate.

Baby aliens skull that got flushed for being deformed.

Is my vote.

a reply to: Nettlas

It's a barnacle stuck to a stone with Super-Glue (TM)

a reply to: Nettlas

You hid your face but let your barcode slip. Good luck!

Shut it down, the terrestrial know...

It looks like coral that grew around a stone. I've seen it before in Florida.

That evil robot in the bottom right corner, I think it made it.

originally posted by: Justso
It looks like coral that grew around a stone. I've seen it before in Florida.

Yeah some type of mineral build-up.

Calcium?

originally posted by: neo96

Baby aliens skull that got flushed for being deformed.

Is my vote.

What do you mean deformed?? O.o

This thread really rocks!

a reply to: Nettlas

Yep a rock in a rock.
The black one was a volcanic range at one time. It got worn down by nature and that river cobble was washed into a big lake, sea or the ocean, where it settled into the sand of the bottom.
Then that sand was buried over time and formed some sort of hi silica stone, which was then uplifted into mountains and eroded away making a new river cobble with a river cobble inclusion.

My guess is a fragment of fossilized bone..

But without seeing it in person i could be wrong

Ask your friendly neighborhood geologist..

originally posted by: DictionaryOfExcuses
This thread really rocks!

Go home.

a reply to: MerkabaTribeEntity

OK, fine. Point taken.

I don't mean to
rock
the boat.

originally posted by: schuyler
It looks to me like an igneous rock surrounded by a sedimentary rock. I can't quite tell because you gave us no "hardness' indication, but that's what it looks like. So the had rock was lying in a place where sediment surrounded it and hardened. Likely it was completely surrounded by the sediment. Afterwards, the combined piece was subject to erosion, in this case likely by wave action, hence your very cool rock.

I was about to say the same, I'm a secret geology geek, I go fossil hunting at Lyme Regis bay in the UK, it's a cornucopia of fossils.
I see lots of stones such as the OP in conglomerate sandstone areas around my region.