just to clarify, in the book it's basically just 'a form of ice that stays ice even when warm'. it was described as an abandoned projected by the military to harden mud for infantry men to cross. just like regular ice crystals, the ice9 crystal pattern 'spreads' across water, but without the need for it to be chilled, eg the body temp water freezes etc, it becomes a 'midas touch' problem to anyone dealing with it.