Have any of you had the experience of a metal object not producing a sound at all. The Cross I found today was on top of the soil with small pieces of gold exposed and I ran over it and no tone at all. I kicked it and lo and behold it was a gold cross. My next thought was it is plastic. I checked the connecting eye which was broken and it was indeed metal. There were two others in area with excal and we layed it on top of the dirt and they only had a very barely audible tone coming into their machines. Is this some kind of freak material in this thing or does this happen occasionally.