E-Trac and small gold...

It looks like our machine is kinda picky on small gold items (for example: earrings, pins etc.) Do you get the same impression? I am very disturbed by my last night finding. My daughter's gold earring 1/2 inch diameter is INVISIBLE :confused: to my detector! Not a chirp, not nulled, constant treshold hum and noting else. I do check fully open (no masking) of course. It will recognize my gold wedding ring well (12-22 range) but nothing small. I hope it is only matter of proper settings to uncover small particles of gold like described above. If you know a trick or pattern that works please share itwith us. This is really making me (and probably many others) nervous. Why? Is my coil damaged or something?