Fired up my Whites DFX after i swung by and picked up a piece of my pyrite. Folks had a discussion as to whether pyrite would set a detector off. Didn't switch coils around. left the 12x10 SEF on. First put it in beach and jewelry mode and almost touching the coil you could hear a little something. Put it in stock prospecting mode and my piece of pyrite depending on the way it passed over the coil ran anywhere from a negative 9 to a plus 12. So pyrite,at least the piece i used sets a detector off.