Picked up some rocks for my second tank, questions...

[zparticle]

So I picked up these three rocks from my neighbor and plan to put them in my 55 gallon tank and start cycling it.

I know the first (on the left) is petrified wood, the second looks like it might have a lot of calcium in it, the third I have no idea. Just was wondering if anyone could I.D. these last two and tell me if they would be bad choices.

The third one I'm not so worried about as it seems almost like obsidian but the middle one scares me a bit.

 

[zparticle]

oops here are the rocks

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These are after they have been covered in water.

 

[Gillie]

The second one may be sandstone/painted rock but I have no clue what the last one is.

 

[zparticle]

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[roydooms]

Cool looking rocks