What kind of rock is this?

Looking through photos & I found some cool tanks. My question is what kind of rock are in these two pictures?

 

First one looks like somekind of base rock inter mixed with volcanic? Second one is Shelf Rock. Good luck finding it though.

 

They both look awesome. I want it. lol The volcanic & shelf rock. T

he shelf rock above is exactly what i was looking for to create my "cliff" I was talking about had I gone ahead with the 75.

 

Here's what I have now, the gray stuff. My LFS, just calls it "dry rock". They don't have a specific name for it.

 

If your handy with a chisel, you can make tufa, base rock whatever you want it to look like.

 

Oh tufa looks like what I have...isn't it?

 

johns rock from reefcleaners isnt to bad. its actually realllly good for base rock

 

Yeah I have seen his rock...it's nice. But I am looking for some unique shape. RC rock looks like the same stuff as BRS & Macro Rocks. Well very similar at least.

 

In a way it does, in the 120, my father has a special blade for his saw, so he made some ledges for me to stack rocks nicer... worked well

 

also check out fiji rock. it has a lot of texture to it, as well as tonga. some hard to find types are not commercially available because they have been banned and such