Is this good rock?

[LostMind]

I have one white thing I think was a sponge on this one rock... it is huge. Must be 6 inches wide, circular and unfortunately, very dead

I think this rock qualifies as porous - it has lotsa caverns and holes in it.

I tossed mine into the tank right away, I have nothing else in there anyways. Now its just a matter of fine tuning everything and hopefully this rock will cure pretty quickly.