Basically yes, but that seems like a waste of a big piece of rock. Why not go to youur LFS and ask if you can get rubble from them at a discount? Most LFS's rock vats have tons of it naturally collecting at the bottom of the vat and since it is generally not desireable to build rockwork in a display tank it is usually not considered valuable to them.
Or, since this is the DIY forum, you could just DIY rock from scratc with concrete. If you want rubble for frag plugs you can make it all uniform size by using egg cartons or disposable paper or plastic cups.
that's a lot of good infp. thanks. it's just that i had about 50 lb of lr. i was going to give to a friend starting a reef tank, and he can't have it. i'm planning on making some of them into rubble and the rest will go into my dp.
BUST OUT THE HAMMER! Put it into a paper sack first tho and give it a few good whacks heavier the hammer the better i use a mini 5 lb sledgebut dont crush too much bust it up but dont turn it to powder