Rodger: I conducted a long search for the grit/gravel that you describe. I finally went to a cemetery stone engraver and asked where he bought the grit he used to engrave the stones. I found a place in the Bronx that carries all sorts of different sized grit which is used for sandblasting operations. I picked up a bag ( 50 lb) of black slag not knowing what I was going to do with it, but it looks great. I used the grit to top dress all my seed pots and have used it as a soil amendment for all my colchicums which have done well. Anyone in the NY/NJ areas looking for the source send me a private email and I'll give you directions and contact info. Arnold