This subject may have already been discussed, but I haven't found it so here goes . . .

I have TONS (ok, not tons, but LOTS) of lava rock - you know, the black and brick red stuff - left behind from the previous owner of my house. I hate using this stuff in my flower beds, and I hate to just throw it away.

Can I smash it up and use it as lava sand? I have a hammer and lots of frustration, so transforming the rock to sand is not a problem.

Lisa-
Have at it, your gardens will benefit from your frustrations. If you have a concrete driveway you may be able to drive over it and accelerate the crushing.
Tony M

Well, that's good news! I thought my little plan would work!

Thanks, Tony, for the advice about driving over it -- didn't think of that!

You can do that but don't expect it to work like the commercial lava sand. Malcolm Beck has a tester he can use on materials to determine how good they are. It seems to be able to distinguish between good lava sand and poor lava sand. And they are not all alike even from the same mine.