It is a good topic to ponder on all weekend.
I have done this in the past, but I decided to revisit the square nail/nugget test.
I didn’t weigh the nugget, but I suspect it was around 6.5 grams.
Using the Fisher GB 2...smallest elliptical coil...with Iron ID mode on (kind of discrimination).
I set a square nail down on the ground –> no signal
Set nugget next to nail –> bright clear signal
Set nail over nugget –> no signal
Set nugget in middle of a pile of nails –> no signal
So yes, nails over and near gold nuggets can mask the signal when using discrimination.
Good reason for digging every signal in certain situations, even if you are using discrimination to predict targets.
For grins, I did the same test using the Makro Gold Racer (round 5” coil). While it did pick up the nugget when it was placed near the nail, it was nowhere as clear and loud as the signal returned by the GB2. The GB 2 won hands down. I suspect this was just due to the elliptical vs. round coil. I think the GB2 was picking up the nugget only because there were two distinct targets.
I really thought the gold racer would have done better on this test. I may have to order their elliptical coil.