Which Garrett detectors will find a coin below iron? Try this test: place a nail on a 2 x 4 stud cutoff about 1.5 inches from a Washington quarter placed on the ground. So the quarter will be approx 1.5 inches below the nail and 1.5 inches away. My GTI 2500 will find the quarter depending on the angle of swing. Swinging across the quarter and coin I get nothing. Swinging 90 degrees to this along the long dimension of the nail I can pick up the quarter but the ID is an average of the two metals. Judging from this, there are still a lot of silvers out there waiting to be unmasked.