Wood, Bone or Weird Rock?

[tekknoir]

I tossed this one in my petrified wood pile because that's mostly what I find out here, but sometimes I see pictures of bone fragments that look similar or that I would have taken for wood had I found it. So what do you guys think? It doesn't stick to the tongue and shows details that could be porousness... but could also not be... There's no obvious cell structure that I can make out.

 

Follow up question: Are there any good ways to tell the difference between wood and bone aside from wood cell structure or visible marrow?

 

This was found in Dona Ana county, NM.

[Rockwood]

Forget about licking anything this well mineralized. That would be even more useless than it normally is. 

I would agree to call this wood, but it is really only a hint of linear texture and plant fiber that is tough to explain.