Talk:Field Trip/@comment-68.83.238.20-20140926004934/@comment-73.38.184.48-20140926015114

You don't know that. The technique could be the same, but the elemental application may be different.

An illusion might be a fire + air application while volcanic glass weapons might be a fire + earth application. Thinking of it that way, the two would be akin to opposite sides of the same coin.