I almost bought a bag of this last week. Then I got to thinking it looks to supply most if not all the same stuff as wood ash. I am fairly certain wood ash contains more pieces and parts as a whole but I am 100% not sure. Ash is amazingly complex and fast acting.
I'm currently trying to make some homemade super soil with all kinds of crazy stuff and almost bought this and greensand to add to it, but I think I have it covered with things I have on hand. If not live and learn and try again.