Definition I was using was that is was a very the structure has alot of air gaps and that the video shows bits breaking of just from a little bounce. That said

Definition I was using was that is was a very the structure has alot of air gaps and that the video shows bits breaking of just from a little bounce. That said brittle is not realy scientific so I'll bow to that and kudos for the wiki link, covers potentual usage as well - thank you.