Riddle Time - Which cell contains the gold key? - Answer

If Cell 3 holds worthless brass, Cell 2 holds the gold key.
If Cell 1 holds the gold key, Cell 3 holds worthless brass.
If Cell 2 holds worthless brass, Cell 1 holds the gold key.
Knowing this brave fool, and knowing that all that is
said cannot be true, which cell contains the gold key?

Answer:  cell 2