Any ideas?

[BirdyD]

Picked up this stone a few years back while visiting the area north of Traverse City on Lake Michigan. Lots of Petosky stones on this beach, but this really looked unusual. I’ve had some time to look at it while at home lately and wondered if anyone had any ideas? So curious because of the triangular shapes and line patterns. 

Edited April 18, 2020 by BirdyD

[grandpa]

A warm welcome to TFF from Austin, Tx. 

 

As to your specimen, I believe it is geological in nature, not a fossil.  It is, nonetheless, a very interesting rock and one that I would keep and place on my "weird rocks" shelf.

 

Again, welcome to the forum.

[BirdyD]

Thanks for the welcome and the reply, grandpa-

 

it already has a place in my cool rocks basket in my living room! 
 

[Fossildude19]

Welcome to the Forum.

 

Definitely geologic in nature.

You might look into counter septarian structures.

Also eroded or water worn boxwork could be a possibility. 

 

[Ludwigia]

Nice rock. It's amazing what mother nature creates sometimes.

[Rockwood]

7 hours ago, Fossildude19 said:

You might look into counter septarian structures.

Fifth post down on the first page of this part of the forum.