There's a little bit of info in here about the superconductor claim.

I have to agree with Sabine that the video of the broken wafer on a magnet does look a lot like diamagnetism.

I've done a demonstration where I condense liquid Oxygen out of the air and pour it between 2 strong magnets. It will "levitate" between the magnets, rather than fall through. Of course it evaporates in a matter of seconds so you have to look fast, but the effect is obvious.

The liquid oxygen is diamagnetic and experiences forces when a "steep" magnetic field gradient is incident upon it.
In more accessible terms... if the magnetic field changes from North to South over a "short" distance, that expresses a force on diamagnetic things.