Just check the bag. It should tell you if they added something to it, although I'm with FireTheft on this one, it is pretty much inert and really wouldn't be able to have things added to it. I could be very wrong however, as I've seen the MG perlite at wally world but passed it up because of the name. I am picking up more perlite today, and I'll check out the MG stuff at Wal-mart and report back if I find different.