I have two suppliers of KMnO4 that I usually use, but they are both slightly different, one is a FINE powder, liked fumed sillica or airfloat charcoal, slightly damp seeming dust, the other is like very small crystals, but very dry, the crystalline nature is more visible in the second one, they both seem to have equal oxidising power, tested against ephedrine HCl, same amount required to produce the ketone, and against glycerine inflamed in most exactly equal times.
Which out of the two seems like the better grade to be buying?