lol I was trying to brake it in a bucket with saltwater and I ended up braking the damn bucket,the floor got all wet.I think it's tonga branch live rock or something like that.
Place the rock on a towel or something and use a hammer and chisel. If you want more than 2 pieces place a towel over the rock and bang away with the hammer. This way you won't have pieces flying all over!
While your at it you can use the towels to dry the floor.
actually if the rock is covered in coraline algea that is a great way to supercharge the spread of it and that method is a good way to help seed other rocks that are dead.
I just use an old large bladed chisel and hammer, I try to score the rock all the way around where I want it to break, not always where it does but, you gotta have a plan to start with!