[warrenfamily95 (OP)]

We found this rock with my grandmother's things.  It's a two toned rock with a hole through the center.  We are wondering what type of rock it is, and what would cause the weird shape?    [ Invalid Attachment ]

[warrenfamily95 (OP)]

One more view... [ Invalid Attachment ]

[JimBob]

Probably a rather soft rock(sandstone or carbonated) as there is an obvious anthropomorphic hole in it.

But no one on this forum is a anthropologist. We are all geologist.

My first thought was that it might have something to do with spinning thread but ..... what do I know?

[warrenfamily95 (OP)]

Thank you for your input!  I was told by someone that since the edges are all uneven that it is not man-made?  I was just wondering how something in nature would result in such an odd shape!  My husband said maybe water had ran over it?  Please ignore my ignorance, we are very amateur rock collectors, but curious none the less!!!

[RD]

Reminds me of scale which has accumulated in a water pipe ...



Speleothem ?

[warrenfamily95 (OP)]

It's funny that you mentioned that, there was a cave on my grandparent's farm in Kentucky.  Maybe this could be a cave formation?

[JimBob]

Now we are getting somewhere.

A part of a large sized super cave straw.

[warrenfamily95 (OP)]

Hmmm, is there a way to tell if it is a cave formation?  Also, someone suggested it might be a piece of ironstone?

[RD]

is there a way to tell if it is a cave formation? 

Can you scratch it with a knife ?, Got any acid ? ... http://www.thenakedscientists.com/forum/index.php?topic=27121.msg287584#msg287584


BTW the tube form could also be a concretion formed around a plant root ...

 [ Invalid Attachment ]

http://geology.about.com/od/more_sedrocks/ig/concretionpics/conctube.htm

[JimBob]

Or a shrimp or crab or worm burrow. Anything that digs in mud. This possibly includes now extinct spiders of whose  habits we know nothing. But spiders will line their holes with debris. Some worms do as well - big worms.

[warrenfamily95 (OP)]

Thanks for the information, I'm so glad we found this site!  My son and I are going to try the acid/scratch test this weekend.  The hole does tunnel back (it doesn't go straight through)so the concretion suggestion is very interesting!  I will share that info with my son also, he will get a kick out of the very large worm theory.