[Hazama adjusts his tie idly, and continues his explanation.]
By signatures like it, I'm referring to the gem in the latch. It's a power source exclusive to this "world" that the brawny dude I used to work with dubbed "Nexite". To an extent, yes it does act like a metal detector, but only for other Nexite. There are other uses for that stuff than cutting open rifts, but that's for another time. As for your second query, let's put it as needing magic to recognize magic. Think about it this way, if you're wanting something to pick up on magic as an energy source, then you need something to compare what you're trying to detect to. Otherwise, you might pick up something like the Azure or Nexite as magic, which they aren't.