If you take into account the fact that Kryptonite is a fictional crystal, I think it would be fine if it left dust when it was dropped…. :p Besides, it makes a good plot point!
I’m soooo glad Lois made it safely to Clark’s apartment. And I’m glad that Martha was there to help her. Now even if Clark doesn’t find out for himself that she is alive, Martha can tell him.
Looking forward to part 8.