Need help with another stone I.D.

[hertzgirlz]

Great necklace--sterling with these cool rocks, but I am clueless--can anyone help?

[old.crows.nest]

Probably wrong but looks a little like fossilized dinosaur bone.

[southernmermaid8]

Interesting....I was thinking some sort of petrified wood so maybe it is some sort of Dino bone.